Form Number: CA 12-12a
Form Number: CA 12-12a
Accident and Incident Investigations Division
Section/division
AIRCRAFT ACCIDENT REPORT AND EXECUTIVE SUMMARY
Reference:
Aircraft Registration
ZS-GBF
Type of Aircraft
Date of Accident
20 January 2014
Type of
Operation
Glider JS 1C 18/21
Pilot-in-command Licence Type
Sporting Gliders
Pilot-in-command Flying
Experience
Total Flying Hours
Age
CA18/2/3/9275
Time of Accident
1025Z
Private - Part 91
54
1234,39
Last point of departure
New Tempe Airport (FATP) – Free State
Next point of intended landing
New Tempe Airport (FATP) – Free State
Licence Valid
Yes
Hours on Type
58,39
Location of the accident site with reference to easily defined geographical points (GPS readings if
possible)
In an open field about 2 NM from New Tempe Airport (FATP).
Meteorological Information
Wind: Variable, 06 gusting 16 knots, Temperature: 32˚C, Dew point: 10˚C
Visibility: CAVOK
Number of people on board
1+0
No. of people injured
0
No. of people killed
1
Synopsis
The tow line attachment between the glider and the tug plane broke at the position of the TOST
ring on the tug plane attachment point during the take-off phase of the flight. During the initial climb
phase the glider moved out of position and under excessive loads tow rope broke while the glider
was at low altitude. The scuffed damaged tow rope could not sustain the excessive loads caused
by the glider being out of position and catastrophically failed. The reason why the glider got out of
position could not be determined.
The time that the glider got out of position the indicated tow speed was approximately 85mph
(±73kts). After the tow rope failed the glider yawed to the left side and the fuselage then
immediately followed, rolling into a steep nose down attitude considered to be a dive straight
toward the ground. The roll moment of inertia was caused by the speed, low altitude, weight and
balance of the water ballast of the glider which probably the pilot did not expect at the time. Due to
the low altitude recovery was not possible.
The tow rope was examined and tested with the aim to determine why it broke. The evidence
found showed that the tow rope had extensive scuffing damage inflicted progressively over an
undeterminable period of operation. The scuffing damage may have been a result of improper
handling of the rope, probably frequent dragging on hard surfaces. The tow rope was visually
inspected over the full length and scuffing damage similar to that where the rope broke was found.
Probable Cause/s
During aero tow operation, the glider inadvertently moved out of position, as a result exposed the
already frail tow rope to a sudden increase in tension due to the excessive load causing it to break.
The glider then yawed to the left side, rolled into a steep nose down attitude considered to be a
dive straight toward the ground.
IARC Date
CA 12-12a
Release Date
20 NOVEMBER 2015
Page 1 of 63
Section/division
Accident and Incident Investigation Division
Form Number: CA 12-12a
AIRCRAFT ACCIDENT REPORT
Name of Owner
: JS1-ZM Partnership
Name of Operator
: JS1-ZM Partnership
Manufacturer
: Jonker Sailplanes (Pty) Ltd
Model
: JS 1C 18/21
Nationality
: South African
Registration Marks
: ZS-GBF
Place
: New Tempe Airport (FATP) – Free State.
Date
: 20 January 2014
Time
: 1025Z
All times given in this report are Co-ordinated Universal Time (UTC) and will be denoted by (Z). South
African Standard Time is UTC plus 2 hours.
Purpose of the Investigation:
In terms of Regulation 12.03.1 of the Civil Aviation Regulations (1997) this report was compiled in the
interest of the promotion of aviation safety and the reduction of the risk of aviation accidents or incidents and
not to establish legal liability.
Disclaimer:
This report is produced without prejudice to the rights of the CAA, which are reserved.
1.
FACTUAL INFORMATION
1.1
History of Flight
1.1.1 The glider, a JS 1C 18/21 aircraft with registration ZS-GBF, was being operated
privately at New Tempe Airport (FATP) by the Soaring Safaris Gliding Club. The
glider was involved in an accident after take-off. During the investigation that
followed several witnesses were interviewed to help determine what had caused the
accident. The witnesses stated the following:
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(i)
Witness #1:

The witness held a glider pilot licence and PPL issued in the United Kingdom
(UK). His cumulative flying experience was approximately 900 hours. He visited
South Africa every year during the local gliding season (November to January)
and was hosted by the Soaring Safaris Gliding Club at New Tempe. On the day
in question, the witness was also preparing to fly another glider aircraft, the last in
line behind the accident aircraft.

He stated that at approximately 1000Z he saw the pilot of ZS-GBF boarding the
aircraft. He was interested in observing the flight of ZS-GBF because on the next
day (21 January) he was due to fly a JS 1 Revelation glider aircraft too. He had
never flown the type before and was interested in observing its structural details,
pre-flight checks and aerotow take-off.

He observed the accident pilot sitting inside of ZS-GBF busy with his pre-flight
checks. During this time the witness decided to do a walkaround of the accident
aircraft to check its fin probe, flaperons, wing tip, canopy and instruments. He
then watched the accident pilot carry out his pre-flight checks. He noted the
aircraft flap setting #1 selected. He did not interrupt the accident pilot during the
pre-flight checks. When the accident pilot had finished his checks and was
waiting for the tug aircraft (a Cessna 182, ZS-CGN) to arrive, the two pilots
started a conversation about the instrumentation fitted on the accident aircraft.

They were still talking when the Cessna 182 arrived. The witness saw two of the
gliding club ground handling personnel attending to the accident aircraft. There
was one hooking up the tow line and another standing on the left side holding the
wing tip level to the ground. The witness helped them by removing the wing dolly
from the right wing. During the take-off, the witness observed one of the ground
handlers (left wing) starting to run next to accident aircraft. The witness was
watching with interest to see at which point into the take-off the pilot would
change the flap settings from #1 to a higher setting. He thought that the take-off
was routine with the wings level and executed well as it was leaving the ground.
The lift-off occurred as the Cessna 182 and glider combination passed the gliding
club hangar.

The take-off proceeded normally, at which time the witness turned his back to the
two aircraft flying away and preparing to board his own aircraft. He did not see
the accident, but he was informed of it later, which resulted in him abandoning his
plans to fly.
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Figure 1 Runway used for take-off
(ii)
Witness #2:

He was the pilot flying the tug aircraft (the Cessna 182 ZS-CGN. He stated that at
approximately 0800Z they had their briefing. The weather forecast predicted that
there would be good CAVOK conditions on the day. During the briefing the
accident pilot decided to fly the glider ZS-GBF again. He had flown this glider on
two previous flights, on 14 January (5,45 hours) and 15 January (2,10 hours)
respectively. The accident pilot intended to fly a record flight.

A total number of three gliders were launched first using tug aircraft ZS-CGN
before the accident aircraft. According to the witness, did the radio
communication checks before taking off. He found the responses to the radio
instructions from the accident pilot to be clear and precise. At about 1020Z, they
started with the take-off, which was observed as routine with lift-off at the end of
the paved section of Runway 36.

Once the two aircraft got airborne, he kept the nose of the tug aircraft down to
allow the airspeed to build up. When he reached the speed of 85 mph (73 knots),
a gentle climb was initiated without allowing the airspeed to decay. He reached a
positive rate of climb with engine RPM 2400 from 2550. He then made a gentle
but shallow turn to the left (5˚ to 10˚). His intention was to pass to the left of the
hill and building on the extended centre line of Runway 36.

After he had passed the hill, he suddenly he felt a severe jerk on the tug aircraft,
as if the tow line was pulling the tail of the tug aircraft to the right. He looked for
the position of the accident aircraft in the rear view mirror, but before he could
locate the glider another jerk followed, after which the tug aircraft started to
accelerate. It felt as though the accident aircraft had got loose.
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
Since he could not see what was happening behind, he decided it was best to
maintain his heading to clear the area. He also called the accident pilot on the
radio instructing him to declare his intentions. His assumption was that the
accident aircraft was in a free flight mode and the pilot was looking for a place to
land. There was no reply from the accident pilot. After several radio calls and
getting no response, he decided to turn back toward the airfield to see if he could
locate the accident aircraft in the circuit. There was no sign of the glider flying in
the circuit. This was when he decided to start a search for the glider in the open
fields along the climb route. He spotted a white object on one of the fields which
turned out to be the wreckage of the accident aircraft. He reported the accident to
the relevant authorities flew back to FATP and landed.
Figure 2 Route flown during the take-off
(iii) Witness #3:
 He saw the two aircraft (Cessna 182 and JS 1 glider) attached by the tow rope
when taking off. After roughly 10 seconds he saw the accident aircraft swaying
(moving from side to side) behind the tug aircraft. The witness did not know whether
the swaying was done deliberately by the accident pilot or was due to thermal
activity or to propeller backwash of the tug aircraft and/or the glider pilot losing
control of the aircraft.
 He observed that the accident aircraft position was just below the tug aircraft. The
swaying movement continued until he saw the tow line get detached or released.
He did not know whether it was done intentionally by either the tug pilot or the
glider. He then saw the accident aircraft being more to the left side of the tug aircraft
and making the medium turn of about 45˚ when the tow line became detached.
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 He observed that the accident aircraft rolled to the left side and entering a spin. The
aircraft nose-dived slightly to the right (using the position of the tug aircraft as the
reference point). Thereafter he heard a slight bang. The tug aircraft was continuing
straight and then turned right into a circular pattern. The tug aircraft did one circular
pattern and then returned to FATP, landing on Runway 18.
(iv) Witness #4:
 He was a flying student at Westline Aviation at New Tempe at the time. He was
walking from the Central Aircraft Maintenance Organisation (AMO) to Westline
Aviation. When he reached Ferreira Aviation, he saw the two aircraft taking off from
what looked like Runway 010. His observation was that the accident aircraft was at
a slightly higher height than the tug aircraft when they reached the row of trees. The
tug aircraft then turned to the left and flew away from the accident aircraft. The
accident aircraft continued straight, starting to climb, and did a tight left turn bank
manoeuvre. The accident aircraft entered what seemed to be a dive with its nose
pointing straight down to the ground. The accident aircraft disappeared behind the
hangars, after which he did not see it again.
Figure 3 Positions of witnesses when seeing the accident aircraft
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1.1.2
1.2
The accident site was an open grass field approximately 2 miles (3,2 km) north of
New Tempe Airport (FATP), at GPS 29˚01, 21S 026˚09,5 and elevation 4495 ft.
Injuries to Persons
Injuries
Fatal
Serious
Minor
None
Pilot
1
-
Crew
-
Pass.
-
Other
-
1.2.1 The pilot was a foreign national (Norwegian).
1.3
Damage to Aircraft
1.3.1 The glider ZS-GBF was destroyed in the accident. Fig. 4 below shows the aircraft
wreckage as it was found immediately after the accident.
Figure 4 Damage caused to the aircraft
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1.4
Other Damage
1.4.1 There was no evidence of other damage.
1.5
Personnel Information
1.5.1 Pilot in Command (PIC) of Cessna 182 (tug aircraft ZS-CGN):
Nationality
Licence Number
Licence valid
Ratings
Medical Expiry Date
Restrictions
Previous Accidents
South African
Gender Male
Age 69
0270098452
Licence Type
Private Pilot
Yes
Type Endorsed Yes
Single Engine Piston, Safety Pilot, Night and Tug Pilot
Ratings
31 January 2017
BRIL – Corrective lenses
None
Flying Experience:
Total Hours
Total Past 90 Days
Total on Type Past 90 Days
Total on Type
1708,00
17,24
16,54
305,51
1.5.1.1 The tug aircraft pilot was also a co-owner of the Soaring Safaris Gliding Club.
Based on information obtained from Soaring Safaris website, he was involved in
gliding operations since going solo in June 1960.
1.5.1.2 He participated in several regional, national and international gliding
championships. He was instrumental in establishing the organisation of the South
African Gliding Club and Soaring Society of South Africa. He was the chairman of
both.
1.5.1.3 He was the director of the 27th World Gliding Championships held at Mafikeng in
December 2001. He has been a chief steward at many world and continental
gliding championships.
1.5.1.4 The pilot’s summary of flights flown using the aircraft from 04 January 2014 to 20
January 2014 is as follows:
(i) Towing – flights flown on 11 days (36 towings totalling about 3 hours' flight
time, on average 3 to 4 towings per day).
(ii) Gliding – flights flown on 6 days (total glider flight time 17 hours 51 minutes,
approximately 3 hours per flight, one flight per day).
Note: Based on the above information, the evidence is that the pilot flew in both disciplines
(gliding and towing) every day for a certain number of hours.
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Experience on JS 1C 18/21 type: The operator indicated the following “the pilot’s
experience in a glider with the size, configuration and weight as follows.
Although the pilot had substantial historical gliding experience, the accident flight
was only his 3rd take-off in a large span (21m) glider and his very first take-off
with maximum ballasted AUW”.
1.5.1.5
1.5.2 Pilot-in-Command (PIC) of glider ZS-GBF:
Nationality
Licence Number
Licence Expiry Date
Ratings
Medical Expiry Date
Restrictions
Previous Accidents
Norwegian
Gender
Male
Age
54
45642
Licence Type
Norwegian GPL
18 August 2014 Type Endorsed
Aerotow & Autotow Launch, Self-Launcher
20 April 2016
None
None
Flying Experience:
Total Hours
Total Past 90 Days
Total on Type Past 90 Days
Total on Type
1234.39
58.39
58.39
8.05
1.5.2.1 A RAASA certificate of recognition of foreign glider pilot’s licence (form number:
RA GPl-09) was submitted by the pilot. The aim of the submission was to validate
his Norwegian gliding pilot licence (GPL). The application indicates that he was
hosted by the International Gliding Club of South Africa and under the care of the
Soaring Safaris Club.
1.5.2.2 The AIID sent an information request to RAASA to clarify whether or not the
foreign recognition application had been received and/or approved (as the
requirement is that a copy of the application should be submitted to RAASA within
7 days). RAASA indicated that they had checked all their records from SSSA and
Soaring Safaris for 2013, 2014 and 2015 to find the pilot's application documents,
but without success. They had no records and no information on file for the pilot.
Accordingly, RAASA did not accept and would have been unable to process such
a document.
Note: According to the operator, they stated that “By mutual agreement with RAASA, the
National Operations Manager of SSSA or his delegates are authorised to validate foreign
Nationals Pilot’s Licenses. The SSSA NOM sub delegates the obligations and privileges
under this agreement to the Chief Flying Instructor (CFI) of Soaring Safaris. The necessary
form of the accident pilot was submitted to RAASA as required in term of this delegated
authority and Soaring Safaris has the email proof of this”.
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1.5.2.3 Based on the above the Soaring Safaris Gliding Club responded that the foreign
GPL recognition process was delegated to specific people at various gliding sites
that he had a lot of overseas visitors. The recognition authority had been
delegated to the Chief Flying Instructor (CFI) of Soaring Safaris on 30 October
2013. As part of the recognition process, the requirement was to complete Form
RA GPL09 and email copies of it to SSSA and RAASA to make them aware of the
licence that had been recognised. They had sent an email to both parties on 7
January 2014. They normally would not receive any acknowledgement from either
of these organisations.
1.5.2.3 The foreign GPL recognition application stated that the pilot's experience had to
total 1100 hours and 1000 solo hours. He had flown the following types: Multiple,
LS4 & 8, LAK 19T, ASK-21, DG505, DUO Discus K13 in the past two years. He
had answered “Yes” to the question if he had any experience flying types similar to
the type to be flown in South Africa.
1.5.2.4 According to his FAI sporting licence, issued by the Norwegian Air Sports
Federation, he was authorised to perform the following activities: GPL aerobatics,
instructor aerobatics, instructor class 2, instructor cross-country soaring, GPL
motor glider, towing and aerotow pilot.
1.5.2.5 He also had vast experience flying microlight aircraft and held a microlight pilot
licence (MPL) issued by the Norwegian Air Sports Federation.
1.5.2.6 He served in the Norwegian military as a pilot and flew F16 fighter jets. He was
trained to fly the F16 type in the United States of America (USA).
1.5.2.7 As the pilot was a visitor from Norway and English was not his mother tongue, and
the comment made on his foreign GPL recognition application stated that “some
doubts were raised about this the last two years”, the investigation deemed it
necessary to look at his proficiency in English and his radiotelephone skills in
order to assess his ability to speak and understand English for radiotelephony
communication for the route he intended to fly on the day. A submission was
received from the gliding club management which was a copy of his Norwegian
radiotelephone licence, valid until 30 September 2017, which indicated that he was
proficient in English at level 5 and that the pilot was fully proficient in both
speaking and understanding English.
1.5.2.8 The accident pilot was found to be very familiar with Soaring Safaris' operational
requirements in and around the aerodrome. According to his flying record, he had
successfully flown several flights from the aerodrome.
1.5.2.9 Another area of importance identified during the investigation was the pilot’s flight
on duty time. The flight on duty time was deemed important because his exposure
to fatigue resulting from the time he spent flying and his workload could have
played a role in the accident. His flying record from 04 January 2014 to 20 January
2014 was as follows:
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Date
Tug
Glider
Launch Time
Launch Height
Pilot Name
Landing
Time
Flight
Duration
Comment
04-Jan-14
CGY
VS
13:10
6400
PIC
17:48
04:38
New Tempe
05-Jan-14
CGY
VS
11:30
6300
PIC
15:00
03:30
New Tempe
07-Jan-14
CGY
VS
13:10
6100
PIC
17:15
04:05
New Tempe
08-Jan-13
CGY
VS
14:00
6100
PIC
16:00
02:00
New Tempe
09-Jan-14
CGY
VS
12:05
6500
PIC
12:48
00:43
New Tempe
10-Jan-14
CGY
VS
12:10
6800
PIC
17:10
05:00
New Tempe
11-Jan-14
CGY
VS
11:05
6100
PIC
17:05
06:00
New Tempe
12-Jan-14
CGY
VS
11:10
6600
PIC
17:45
06:35
New Tempe
13-Jan-14
CGY
VS
12:35
6100
PIC
18:00
05:25
New Tempe
14-Jan-14
CGY
ZM
11:30
6100
PIC
17:15
05:45
New Tempe
15-Jan-14
CGY
ZM
12:55
6400
PIC
15:15
02:20
New Tempe
16-Jan-14
CGY
ZZ
12:20
6100
PIC
16:15
03:55
New Tempe
17-Jan-14
CGY
VS
12:35
6100
PIC
18:58
06:23
New Tempe
18-Jan-14
CGY
VS
12:30
6100
PIC
12:50
00:20
New Tempe
18-Jan-14
CGY
VS
13:40
6100
PIC
15:40
02:00
New Tempe
20-Jan-14
CGN
ZM
12:20
4800
PIC
00:00
New Tempe
58:39:00
1.5.2.4 According to the above flying record information, the pilot did not fly on 06 January
2014 and 19 January 2014.
1.5.2.4.1 Part 91 stipulates that pilots who are not subject to an approved flight time and
duty period scheme shall fly 10 hours within a 24 hour period. No anomaly was
identified in relation to the specified regulation.
1.5.2.4.2
According to the aircraft manufacturer, they stated “Gliders are aircraft with no
engine, or if fitted with an engine normally not able to fly under power for more
than 1 hour. Glider flights in South Africa in excess of 10hrs are very rare,
almost impossible. Exceeding 10hrs flight time in a 24 period is not practical
and is therefore not controlled”.
Note: However, it is important to take note of the following regulation which states “no
person shall act as a crew member of an aircraft if he/she knows or suspects that he or
she is suffering from or, having due regard to the circumstances of the flight to be
undertaken, is likely to suffer from fatigue to such an extent that it may endanger the safety
of the aircraft or its occupants." The issue of flight duty time was discussed with Soaring
Safaris management, and they indicated that there were no duty time restrictions for
recreational gliding.
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1.6
Aircraft Information
Airframe:
1.6.1 Cessna 182 Tug ZS-CGN
Type
Serial Number
Manufacturer
Date of Manufacture
Total Airframe Hours (At time of Accident)
Last MPI (Date & Hours)
Hours since Last MPI
C of A (Issue Date)
C of R (Issue Date) (Present owner)
Operating Categories
Cessna 182A
34611
Cessna Aircraft Company
1957
Unknown
Unknown
Unknown
Unknown
12 March 2013
28 June 2011
Magalies Gliding
Club Operations
Standard Part 91
Engine:
Type
Serial Number
Hours since New
Hours since Overhaul
Continental O-470-L
82133-2-L-4
Unknown
Unknown
Propeller:
Type
Serial Number
Hours since New
Hours since Overhaul
Hartzel
HP-216A
Unknown
Unknown
Note: Information indicated as unknown could not be recovered during the investigation.
1.6.1.2 Aircraft documentation: The validity of the aircraft documentation was checked
during the investigation. No anomaly was identified.
1.6.1.3 Aircraft maintenance: The last mandatory periodic inspection (MPI) was carried out
by an AMO. After the MPI was certified, a release to service (CRS) was issued.
The CRS was valid for 100 hours or 12 months, whichever comes first. No
anomalies were identified in the aircraft maintenance. The aircraft was airworthy.
Note: No anomalies were identified in the performance of the aircraft during the operation.
The aircraft was in a good serviceable condition and the pilot did not report any defects or
systems malfunctions.
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Figure 5 TOST ring & tow line connection
Figure 6 Tow line still attached to glider
Figure 7 Broken end of tow line
1.6.1.4 Fuel: The evidence was that the aircraft had sufficient amount of fuel carried on
board as required for the gliding operation on the day.
1.6.1.5 Tow line failure: The aircraft was used as the tug aircraft. The aircraft was towing
the gliders using a tow line retraction device installed on its tail end. The
information obtained during the on-site investigation indicated that during the takeoff the tow line failed at the position of the TOST ring attachment at the tug
aircraft.
1.5.1.6 According to Soaring Safaris Gliding Club management, they used a 10 mm
diameter polypropylene and TOST rings as per the manufacturer’s specifications
as indicated in the pictures above. They always started the gliding season with
new tow lines. It was the responsibility of the tug aircraft pilot to carry out
inspections of the tow lines every day. It was a visual inspection which included
checking of the tow line coupling, the ring pair for weak link and excessive wear,
release mechanism for excessive dirt and improper functioning.
Note: Whenever any of the tow lines was worn where it was attached to the TOST rings,
the affected towropes/lines would be respliced on an “on condition” basis.
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1.5.1.7
The Soaring Safaris Gliding Club provided a copy of data sheet for the tow line
used. The data sheet indicated the following about the tow line:
Rope Products by RAM Fibre Robe Products
Polypropylene Rope
Features
Most Common Use
– a synthetic fibre rope made –Resistant to most acids.
-Cargo Nets.
from a split film extruded tape. -Reasonably abrasion resistant.
-Rope Blocks.
- Does not absorb water.
-Cargo Securing.
- Floats, specific gravity is 0.91.
-Mining Applications.
- Does not rot.
-Fishing Applications
- Has a low stretch factor
Specifications [Strand and Flexply (8 Strands Plaited) Ropes
POLYDIAMETER mm
10 mm
PROPYLENE
MASS/220M Kg
10
3 AND 8
MASSMETRE g
22
STRAND
B. FORCE kgf
1425
1.5.1.8
The Soaring Safaris Gliding Club also indicated that the tow line used length
was 55 m from TOST ring to ring. The recommended minimum length was 50 m,
of which the extra 5 m allowed for resplicing as required.
1.5.1.9
The TOST ring was found still attached to the retraction device on the tug
aircraft.
Note: Based on the above information, it was deemed important to calculate the tow line
strength. The SACAR and CATS were reviewed with the purpose to find tow line strength
standards and/or requirements published. Regrettably, none were found.
 The calculation was therefore carried out using US requirements (14 CFR Part 91,
section 91.309), which state that the minimum tow line strength is 80% of the glider's
maximum certificated operating weight. The maximum strength is twice the maximum
certificated operating weight. The maximum certificated operating weight can be found
in the specific POH for the glider and may be the maximum certificated gross weight at
take-off.
Calculation:
(a)
80
100 x 660 kg = 528 kg, minimum strength value.
(b)
2 x 660 kg = 1320 kg, maximum strength value.
NB: Specification – B. Force = 1425 kgf, which is twice the glider's maximum certificated
operating weight. This suggests that the relevant tow line breaking strength was within
limits by approximately (1425 kgf – 1320 kg = 105 kgf).
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
Thus, if the tow line has a breaking
strength more than twice the maximum
certificated operating weight of the
glider being towed, a safe link (weak
link) has to be installed at the point of
the attachment of the glider and tug
plane
with
breaking
strength
requirements.
Airframe:
1.6.2 JS 1C 18/21 glider ZS-GBF
Type
Serial Number
Manufacturer
Date of Manufacture
Total Airframe Hours (At time of Accident)
Last MPI (Date & Hours)
Hours since Last MPI
C of A (Issue Date) (Expiry Date)
C of R (Issue Date) (Present owner)
Operating Categories
JS 1C 18/21
1C-056
Jonker Sailplanes (Pty) Ltd
2013
198,00
05 November 2013
9:00
179,00
07 November 2013
06 November 2014
21 August 2013 JS1-ZM Partnership
Standard - Part 91
1.6.2.1
Aircraft documentation: The validity of the aircraft documentation was checked
during the investigation. No anomaly was identified.
1.6.2.2
Aircraft maintenance: The last annual inspection was carried out at the facility of
the aircraft manufacturer (Jonker Sailplanes (Pty) Ltd, authorised under AMO
151). After the annual inspection, a release to service (CRS) was issued stating
that the aircraft was maintained in accordance with approved maintenance
schedule (AMS). No anomalies were identified in the aircraft maintenance.
Note: No anomalies were identified in the performance of the glider during the operation.
The aircraft was in good serviceable condition and the pilot did not report any defects or
systems malfunctioning.
1.6.2.3
Fuel: Not applicable. The glider was not fitted with an engine.
1.6.2.4
Mass and balance: The aircraft manufacturer assisted with mass and balance
calculation with the aim to determine whether or not the aircraft was operating
within prescribed limitations. See mass and balance calculation below:
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Note: The water ballast system is full when the glider has integral main tanks in the wing,
each holding approximately 90 litres of water and two trim tanks in the vertical fin. The tail
ballast tanks consist of an expendable tank of approximately 7,5 litres and a nonexpendable tank of approximately 4,5 litres. The 21 m wing tips have a capacity of
approximately 17 litres each.
1.6.2.5 Based on the mass and balance certificate, the empty mass is 755,3 lbs (342,6 kg)
and the maximum mass is 1322,77 lbs (600 kg). The mass and balance
calculation above shows that the total on the day was 1474,89 lbs (669,0 kg),
which means that the glider was overweight by 669 kg – 600 kg = 69 kg. The
evidence is that the total mass of 668,5 kg determined by the manufacturer differs
by only +1 kg in this regard.
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1.6.2.6 The mass and balance calculation also determined that with the glider’s weight of
668,5 kg with water ballast, the flying centre of gravity (CG) position would be at
380,2 mm/moment 254,1 kg.m and with expendable water ballast dumped at
374,8 mm/moment 167,5 kg.m. See graph of 21 m configuration (CG envelope):
Note: The CG envelope graph shows that the CG of the aircraft was outside the envelope
on the aft range.
1.7
Meteorological Information
1.7.1 The meteorological information below was obtained from the South African Weather
Service. The METAR information was for FABL, which is the nearest weather
station to the location of the accident. The METAR was as follows:
Wind direction
Variable
Temperature
32˚C
Dew point
10˚C
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Wind
speed
Cloud
cover
06 Gusts 16 knots
Visibility
CAVOK
Nil
Cloud base
Nil
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1.8
Aids to Navigation
1.8.1 New Tempe Airport is used for recreational and general aviation operations. The
aerodrome does not have any radio navigation aids installed, and these were not
required by the applicable regulations.
1.8.2 The two aircraft (tug aircraft and glider) were flown under visual flight rules (VFR).
The aerodrome used has no radio aids to navigation. Due to the operation of the
aircraft (visual flight), the aerodrome ground aids (markings and signage) were
used.
1.8.3 The aircraft were fitted with standard navigation equipment approved by the SACAA
on their equipment list. The pilots did not report any malfunction or defects
experienced with the navigation equipment in flight. During the investigation the
navigation equipment was checked and it was determined that it was in good
serviceable condition prior to the accident.
1.9
Communications
1.9.1 Both aircraft were fitted with appropriate VHF radio communication equipment
approved by the SACAA. It should be noted that there was no report of a defect
and/or malfunction experienced with the radio equipment. The investigation found
that the radio equipment was serviceable prior to the accident.
1.9.2 As FATP is an unmanned aerodrome, no ground communication equipment was
installed. The aircraft operating to and from the aerodrome were required to
broadcast their intentions on the general area frequency of 131.3 MHz. According to
Soaring Safari’s briefing information, glider pilots are advised to “keep the radio on
this frequency while within 25 km of FATP up to Krugersdrift Dam in order to
maintain general situational awareness of both glider and powered traffic”. This
would have ensured compliance with the unmanned airfield communication
procedures.
Note: Glider pilots are required to prefix any calls with the words “Glider”.
1.9.3 Based on the Aviation Directory Book, FATP had a radio frequency 124.4 MHz, but
it was available for AFIS and on weekends only.
1.9.4 The tug pilot stated that before they started the take-off, he carried out radio
communication checks with the glider pilot and his observation was that the pilot
responded satisfactorily to the instructions over the radio. They did not talk again on
the radio until he felt the tug aircraft jerking. He called the accident pilot requesting
that he declare his intentions, but there was no reply. He did not know what was
happening with the glider.
Note: Neither aircraft transmitted an emergency call such as MAYDAY and/or PAN-PAN
on FATP frequency 131.3 MHz or FABL frequency 124.3 MHz.
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1.9.5 According to Bloemfontein Airport (FABL), Air Traffic Control Unit (ATCU), the
occurrence log states the following:
(i) At 1025Z, the SAAF Oryx helicopter with call sign “BLIZZAARD” reported on
approach frequency 124,3 MHz information of a fatal glider accident north of the
threshold of Runway 28 at FAPT. The crew of the helicopter advised ATC that
they were going to descend and assist. The ATSU then sent out a DISTRESFA
alert message. The FAPT glider window “airspace” was active at the time with
part of FABL TMA being Class G airspace.
(ii) At 1028Z, the ATSU informed the Soaring Safaris Gliding Club management of
the accident.
(iii) At 1038Z, the ATSU advised the SAPS, SACAA and ARCC of the accident.
(iv) At 1050Z, the SAAF Oryx helicopter crew confirmed that it was a fatal accident.
1.10
Aerodrome Information
Aerodrome Location
Aerodrome Co-ordinates
Aerodrome Elevation
Runway Designations (Grass/Tar/Bricks Surface)
Runway Dimensions
Runway Designations (ASPH Surface)
Runway Dimensions
Runway Used
Approach Facilities
New Tempe Airport - Bloemfontein
S290157.77 E0260928.82
4526 ft
36/18
27/09
31/11
800m
01/19
28/10
1300x10
1200x15
36
None
1.10.1 Gliding Flying Area: According to the Soaring Safari Club website, the gliding flying
area in Bloemfontein is vast and varied with few restricted areas. The gliders have
to fly west to clear the Bloemfontein TMA, thereafter fly southwest into the dry areas
of the northern Karoo or north-westerly right up to South Africa’s border with
Botswana or fly east to the Maluti Mountains and the northern Drakensberg.
(i)
For take-off from Runway 36 at FATP, the runway has a 300m tar strip.
There is an addition of brick stretching a distance of 200 m from the end of
the tar strip. The length of the combination of tar and brick surface equals
500 m, which greatly reduces the dust.
(ii)
In the majority of wind conditions, gliders operate exclusively from the grass
runways. The club uses Cessna 182 aircraft as tugs because they give good
rates of climb in hot and high conditions. Given the right weather conditions,
they are able to climb to FL145 above FATP.
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1.10.2 The SACAA Aeronautical Information Publication (AIP) specifies the following flight
procedures for gliding operations:
(i) Gliders must make all circuits to the east of the aerodrome when using airstrip
18/36. When gliding operations are in progress at the aerodrome, FABL ATC
will warn all relevant aircraft of the said gliding activities.
Figure 9 Google Earth map showing FATP and Runway 36 used
Figure 8 Runway length
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1.10.3 Airspace: FABL receives scheduled flights, military flights and some general
aviation movements. It is located about 15 km southeast of New Tempe. FABL
airspace is protected by its CTR, TMAs and CTA that connect it to the upper airway
network.
1.10.4 To allow gliding activities to take place at FATP, a window exists in the airspace
that allows gliders access to the unrestricted or less restricted airspace to the north,
west and south. The boundaries of the FATP gliding window are defined by clearly
visible ground features, being the Bultfontein road on the eastern boundary, the N1
Highway on the south-eastern side and the Dealesville road and Abramskraal on
the southern side.
1.10.5 FAR 29 is a military training area that is used for ballistic training and for army/air
force training. Military helicopters fly in this area and occasionally large calibre
artillery weapons are fired. These activities take place in the south-eastern corner of
this area.
1.10.6 Parachuting: The Soaring Safaris Briefing Notes advise glider pilots of parachuting
activities occasionally taking place at FATP, normally on the western side of the
airfield. These will be either sports parachutists (using Cessna aircraft) or military
(using
C130
Hercules
aeroplanes
or
Oryx
helicopters). In case of
parachuting activities taking
place at the airfield, this
information
will
be
communicated to the glider
pilots during their morning
briefings. Any unforeseen
flying activities will also be
reported on the airfield
frequency (131.3 MHz).
Note: When parachuting is in
progress, gliders are required to not
overfly the airfield. They are advised
Figure 10 Airspace window used by gliders
to remain clear of the parachute drop
zone to the north-western and northern side. If a glider wants to land, the pilot should plan
to fly a circuit well to the eastern side of the airfield to avoid any conflict with the drop zone
on the western side.
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1.10.4 FATP General Aviation and Civil Aviation Training Flying Activities: FATP lies in an
uncontrolled airspace. Apart from the SANDF, SAAF and Soaring Safaris Gliding
Club flying activities at FATP, it is very important to acknowledge the other flying
disciplines, such as general aviation, civil aircraft flight training and microlight flying
activities from FATP and in the area.
1.11
Flight Recorders
1.11.1 The civil aviation regulation (CAR) does not require that flight recorders be installed
in aircraft operating in this category.
1.12
Wreckage and Impact Information
1.12.1 Description of the accident site: The accident site is located in the vicinity of an
agricultural area. There are wide open grass fields of farmland all around the site.
The terrain is mostly flat, but there is a small hill (“koppie”) toward the eastern side
of the site. The surface at and around the site is both prepared (ploughed) and
unprepared (unploughed) ground. In some areas, including the place where the
wreckage was found, the ground is dry, hard and uneven.
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1.12.2 There are two rows of tall (20 m to 30 m) trees on the northern side of the accident
site. These trees are located on the extension of Runway 36, about 2 to 3 km from
the airfield perimeter security fence. In order to get to the accident site dirt roads
were used. The property is protected by a wire fence. There is a farmhouse on the
western side, approximately 300 m away, and a large church building on the
eastern side approximately 500 m away from the main wreckage. See Google
Earth picture below illustrating all the identified landmarks:
Figure 11 Landmarks surrounding the airport and accident site
1.12.2 General description of the site and wreckage distribution pattern: The two aircraft
were observed taking off from Runway 36. Both were flying in a northerly direction
following the runway heading. The evidence indicates that after the aircraft
became airborne, with the glider being towed about 55 m behind, the tug aircraft
made a shallow 5˚ to 10˚ turn to the left expecting the glider to follow. This turn put
the tug aircraft on a north-north-westerly heading (NNW - 355˚ to 350˚). According
to the tug aircraft pilot, he turned left to avoid collision with the farmhouse and
church building on the hill located on the extension of Runway 36. The height of
both aircraft (tug aircraft and glider) was estimated to be approximately 100 ft. to
300 ft (30 m to 100 m).
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Note: The evidence is that at this point both aircraft were climbing, attempting to reach first
circuit height and launching height of 4800 ft. However, at first the tug aircraft pilot
suddenly and without warning felt a severe jerk that caused his tail end to sway
uncontrollably to the right. Then there was another but stronger jerk in the same direction
(to the right), after which the tug aircraft's speed suddenly increased, which was an
indication that the tow line had failed. The failure of the tow line resulted in the two aircraft
becoming separated from one another.
1.12.3 Based on the above information it is evident that the glider somehow inadvertently
moved out of position which contribution was excessive loads on the tow line
causing it to fail while at low altitude.
1.12.4 Probability of a stall was investigated. The glider manufacturer and operator
contribution assisted. The following facts were considered:
(i) The indicated tow speed was approximately 85mph (±73kts). The stall speed of a
fully loaded JS-1C glider (21m) is about 57kts, there was a margin of some 16kts
above the stall speed, which is more than adequate for controlled flight after the tow
line broke. Both aircraft was flying significantly above their stall speeds.
1.12.5 The impact, attitude and configuration of the aircraft when impacting the ground:
(i) Attitude: The wreckage investigation showed that the glider yawed to the left side
and the fuselage then immediately followed, rolling into a steep nose down attitude
considered to be a dive straight toward the ground. It is possible that roll was
caused by the speed, low altitude and/or weight and balance of the water ballast
acting on the glider.
Note: As per SSSA POH, it states “Aero towing (tugging) with water ballast must be
discussed as the increased inertia in the wings causes increased adverse yaw effects”.
(ii) The JS-1C glider carries water ballast in both the inner and outer wing panels. The
fully ballast status most probably had an impact in the glider entering a roll moment
of inertia in a way which the pilot did not expect at the time. Due to the low altitude
recovery was not possible. The glider was found completely destroyed, lying
inverted and facing east towards the church building on the side of the hill.
Note: The wreckage investigation showed that the right wing tip struck the ground first
during the aircraft turning. Also, it is evident that the right wing tip hit the ground before the
nose and/or left wing, as the right wing was found completely broken. The impact marks
on the ground caused by the right wing were much more pronounced than those of the left
wing. After the wing tip hit the ground, the leading edge of the right wing struck the ground,
causing that wing to be destroyed.
1.12.6 In the Aircraft Accident Investigation Book, Second Edition by Wood/Sweginnis, the
author makes the following statement: “that whenever an aircraft is seen to have
impacted the ground at a high angle and low velocity, it is evident that the impact
crater will be shallow and the aircraft will be largely intact. There won’t be a lot of
wreckage strewn around the crater.
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Also, in many general aviation aircraft the aft part of the fuselage connecting the
empennage to the cabin is not particularly strong. Its sole purpose is just that; to
connect the tail to the rest of the aircraft. Since the tail has quite a bit of mass, it is
not unusual for the tail to keep going until and when the front of the aircraft comes
to a stop. Depending on the impact angle (and the geometry of the aircraft) the tail
will either go over the top or under the bottom of the rest of the aircraft; buckling the
aft fuselage in the process. This over or under phenomenon is a pretty good clue as
to whether the impact angle was greater or less (nominally) 45˚”.
1.12.7 The glider main wreckage was found at location GPS 29˚01̍16.80̍̍ S 026˚09̍34.73̍̍
and elevation of 4511ft. The position of the wreckage was found to be at
approximately 2 kilometres from the airfield in a northerly direction. The glider
wreckage and ground impact marks were investigated. See picture below showing
the location of the main wreckage in relation to FATP and Runway 36.
Figure 12 Location of accident site (Google Earth)
1.12.8 The investigation determined that the glider wreckage and ground impacts can be
categorised as being consistent with a low velocity and high angle as indicated
above. See pictures showing a location of the main wreckage, impact crater and
ground impacts:
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Figure 13 Ground impact marks left by wing
1.12.9 All the loose debris was found scattered to the front of the wreckage, which further
supports the low velocity and high angle theory. The cockpit structure was
completely destroyed. The cockpit debris was found at the impact crater, with no
indication of skidding or yawing. It seems as though the canopy was still closed at
the time the nose struck the ground, as the canopy jettison control system was still
in the closed position.
1.12.10 The tail section of the glider broke off just aft of the wings and came to rest on the
right of the fuselage.
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1.12.11 The main landing gear was found still in the extended position. According to the
operator, “the landing gear would have been down for the take-off, and it is
standard practice to leave it down for the duration of the tow until the glider
releases and goes into free flight”.
1.12.12 The air brakes were found unlocked, which is an indication that it was extended or
activated at some point during the sequence of events. According to the operator,
they stated that “Because the dive brakes use a mechanical over centre lock that
can be easily be overcome by the pilot’s arm strength, there is no significance to
the dive brakes being found open post-crash”.
Note: The aircraft manufacturer’s observation was that “the airbrakes were retracted
during impact as seen by witness marks inside airbrake boxes. When the wings are swept
forward during a vertical impact, the airbrakes are likely to be unlocked”.
Figure 14 Main wheel extended
Figure 15 Air brake unlocked
1.12.13 The tow line was found still attached to the nose hook-up point. The quick
release cable connected to the release hook was found intact. The tow line was
lying in close vicinity of the main wreckage.
1.13
Medical and Pathological Information
1.13.1 The accident pilot held a valid Aviation Medical Certificate without any restrictions.
There was no evidence or report of the pilot suffering any medical condition that
may have impacted negatively on him when flying the aircraft.
1.13.2 A document identified as GW 7/15 submitted by Department of Health: Provincial
Government of the Free State Province Forensic Pathology Services, Bloemfontein,
reports on the post-mortem medical examination on the body of the accident pilot
conducted on 21 January 2014. The medico-legal post mortem examination
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concluded that the cause of death was multiple injuries sustained.
1.13.3 Specimens identified as TX 032000 were retained during the post-mortem
examination for the purpose of conducting toxicological analysis. The specimens
were taken to a laboratory for the analyses. The laboratory had not released the
toxicology results by the time the report was completed; when the results become
available and are found to have a significant impact on the cause of the accident,
the investigation will be reopened.
1.14
Fire
1.14.1 There was no evidence of pre- or post-impact fire.
1.15
Survival aspects
1.15.1 This accident was not survivable. Based on the wreckage and impact investigation,
it was determined that the aircraft impacted the ground at a very high angle and low
velocity. When the aircraft impacted the ground, the cockpit was destroyed. The
pilot was fatally injured.
1.15.2 According to witness #2, the pilot would normally strap on his parachute prior to
getting into the cockpit of the glider aircraft. Once inside the cockpit sitting he would
then fasten his lap straps and shoulder harnesses. During the wreckage
investigation it was determined that the pilot was safely strapped in with the safety
belt and harnesses as indicated by the witness.
1.15.3 According to witness #2, he alerted the search and rescue team about the accident.
The search and rescue team arrived on the scene within approximately 10 minutes
after the accident. They found the body of the pilot strapped in and had to first free it
from the wreckage.
1.15.4 The investigation team found that the pilot was still wearing his backpack
emergency parachute. The parachute was estimated to weigh approximately 6 kg.
Upon enquiry, the Soaring Safaris Gliding Club said that they did not know whether
the pilot had ever received parachute training and/or held a related licence.
1.15.5 Oxygen system: The glider had an MH oxygen system installed. The oxygen
system is fitted for use should the pilot fly at altitudes where a decrease in oxygen
levels and reduction in partial pressure may cause hypoxia. The Soaring Safaris
Gliding Club suggests that pilots should use the oxygen system below 10 000 ft
during the first one or two days of flight. The remote shutoff valve control lever,
which is located in the overhead console above the pilot seat on the roof, opens or
closes the system.
1.16
Tests and Research
1.16.1 Examination and testing: The tow line S/N #056 was recovered from the accident
scene for further investigation by CrashLAB to determine the reasons for its failure.
CrashLab issued out an expert examination report, document number AA1-005-0614 dated 05 June 2014 with heading: “Tow line failure, JS1C Sailplane Aircraft, No.
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ZS-GBF”. The service provider's report stated the following:
(i) During the take-off the tow line failed at the position of the TOST ring
attachment at the tug aircraft end, leaving the glider uncontrollable and leading
to a fatal accident.
(ii) The tow line in question conforms to a typical 3 strand “2” construction
manufactured from multifilament polypropylene. The tow line release
mechanism utilised on both the tow and glider aircraft was the TOST system.
(iii) The visual investigation revealed a fracture at the position of the TOST ring (tug
aircraft end). Closer inspection of the tow line spliced around at the glider end
revealed extensive scuffing damage as well as fractured tow line yarn filaments
at various positions along the tow line length. The installed TOST ring revealed
extensive wear damage as well as abrasive wear on the tow line protective
sheath.
(iv) The considerable damage inflicted to the TOST ring, towrope and protective
sheath suggest that the tow line was not handled in an appropriate manner and
can be attributed to being dropped behind the tug aircraft on hard surfaces after
landing.
1.16.1.2 CrashLAB also carried out three tensile break (UTS) load tests on selected
sections of the tow line including the glider aircraft TOST release end. The
fractured ends revealed that the tow line failed one yard at a time. The section
tested with the TOST ring on the glider aircraft end failed in the tow line and not
at the spliced end.
1.16.1.3 CrashLAB then concluded their inspection/examination stating that “the primary
causational factor in the failure of the tow line is the damages inflicted unto the
tow line at the position of the TOTS ring at the tug aircraft end which resulted in
the ultimate failure thereof during the take-off phase of the launch”.
1.16.2 During the metallurgical testing the tow line was subjected to three break load
tests on selected sections (mid-section 4 m length, adjacent glider end section and
glider end with TOST attached) of the tow line. The test results was that the tow
line failed (loads applied 683,18 kgf, 644,6 kgf and 633,24 kgf) on the yarns at the
time. The variation in fracture geometrics between the tested samples and
accident samples implies that a large fraction of the rope at the accident break
point did not fail under a singular overload, but over an undeterminable period of
operation.
1.16.3 AIID wreckage investigation: The document AS INV Manual Annex 6-1 filed on 20
January 2014 was filled with impact information determined during the onsite
investigation. The identified document states the following:
(i) All the flight controls were examined and found to be satisfactory. The damage
caused to the flight controls resulted from the accident. The flaps were found
to be at setting 4 down travel position (this represents a deflection of +13,5˚),
which is acceptable for this phase of the flight.
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(ii) The retractable main wheel was found extended.
(iii) The air brakes were found unlocked, which indicates it was extended or
activated. According to the aircraft manufacturer,
(iv) The glider water ballast tank was found to be full of water.
(v) The cockpit/cabin area completely collapsed during impact.
(vi) The pilot had a backpack type of emergency parachute. It was not activated to
deploy.
1.16.4 Manufacturer's wreckage testing: The wreckage was recovered from the accident
site in Bloemfontein and taken to the facility of the glider manufacturer at
Potchefstroom, where it was reconstructed by the manufacturer in the presence of
the investigation team with the intention to identify and interpret the relationship
between the deformed/damaged components. All the flight controls were again
examined and tested by the manufacturer. The manufacturer concluded that all
the flight controls were accounted for; they were free moving and operating as
required. No anomalies relating to structural and/or control linkage failures were
identified on the wreckage.
1.16.4 Navigation equipment testing: The investigation team also recovered a Samsung
Galaxy 7 computer tablet. The tablet is normally attached to the canopy on the
right-hand side and mounted on a suction cup and is used by the glider pilot for
navigation purposes. The aim of recovering the tabled was to download the flight
information possibly loaded on it. The tablet was sent to the telecommunications
service provider (Vodacom) to assist in retrieving the flight information. However,
due to the damage the tabled sustained in the accident it was not possible to
retrieve any data.
1.17
Organisational and management information
1.17.1 Part 149 applies to the approval and operation of organisations whose members
operate for recreational purposes. Complying with the set regulation, the DCA
designated a body/institution (RAASA) as the body governing recreational and
sport aviation in South Africa. RAASA has the responsibility to manage, control
and oversee aviation recreational organisations and sport and recreational aviation
in South Africa, including the issuing of all related licences and authorities to fly.
1.17.2 In terms of the provisions of Part 149, RAASA as the designated body/institution
issued an aviation recreation organisation approval certificate (ARO/003) to
Soaring Society of South Africa (SSSA). The approval certificate issued to SSSA
makes it responsible for safety oversight of gliding and soaring in South Africa.
The safety oversight responsibility of SSSA in this regard includes that it oversees
and develops the safe operation of its members. SSSA supervision will be in the
form of advice and, where necessary, control to the extent necessary to ensure
safety and regulatory compliance. SSSA's policy expects individual SSSA affiliates
to take responsibility for their gliding operations and to conduct such operations
with appropriate supervision.
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Note: Gliding operations are conducted by affiliated members with their own facilities and
resources. These affiliates are administered as autonomous organisations, being clubs
(societies) or Section 21 companies, each with their own management structure and
SSSA-approved constitution. For safety purposes, these organisations must operate to the
standards defined by SSSA in its governance manual, ARO MOP and advisory circulars.
1.17.3 The Soaring Safaris Gliding Club is one such affiliated member. It has been in
existence for about fourteen years (since 2002). It conducts its operations at New
Tempe Airport (FATP) in Bloemfontein. Its gliding operations are seasonal, usually
from November until February each year. During this period many glider pilots of
foreign nationality will come to do gliding in South Africa. The Soaring Safaris
website states that all pilots, whether or not they are hiring their gliders or flying
their own gliders, are required to pay a certain predetermined club fee. The fee
covers the costs of usage of club facilities for the duration of their stay. There are
also separate weekly glider hiring fees for each type of aircraft.
1.17.3.1 The Soaring Safaris Gliding Club operates the following glider types: Nimbus 3
24.4wl-HS, Ventus B 15/16.7-GD, LS4-98, LS6 15/18-JCB, ASH25-162,
DISCUS B-JMM, LS7wl-PE, ASW 27b-VS, JS 1 Revelation and Duo Discus-UT.
Note: Soaring Safaris flies at FATP and shares its facilities with the Bloemfontein Gliding
Club.
1.17.4 According to the Soaring Safaris Information and Briefing Notes, a pilot can only
be allowed to fly the aircraft of the gliding club when his/her foreign glider's pilot
licence (GPL) is recognised and its competency or currency is confirmed. It is the
responsibility of each visiting pilot to ascertain or ensure that all required
documentation is valid.
1.17.5 The policy of the club is that every visiting pilot should have a face-to-face site
briefing with the gliding organisation management to ensure that all critical
information is fully comprehended, especially concerning the latest airspace
restrictions and derogations.
1.17.6 The Soaring Safaris Gliding Club holds briefings every morning at 10:00. Typically
the briefing includes a review of the previous day’s flights, safety information, an
extensive weather briefing followed by task setting. All gliders have tow-out gear
and there are three Soaring Safaris vehicles available for towing the gliders to the
launch point, but in the event that these are all in use, there are tow-out ropes in
the hangar that can be used with a car without a hook.
1.17.7 Extra care must be taken if towing out after glider launching has started. Runway
36 has restricted width outside the hangar, so a glider pulled out of the hangar
paved area or emerging around the corner from the shade netting area will block
launching. Procedures will be given in the morning briefing, but the usual
procedure is to wait until there is a gap between launches (and landing tugs) to
tow through the ‘pinch point’ outside the hangar, and then turn right on to 09/27
and then left onto 31 to reach the 36 launch grid area. This can be done with
minimal impact on the launching.
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1.17.8 Views from Jonker Sailplanes (Pty) Ltd: According to the aircraft manufacturer, they
stated that “Tow ropes should break to protect the structure of the tow plane and
glider, and many simulatee rope break exercises are performed during training
where the cable is deliberately released. No accident has ever happened after a
simulated rope breaking exercise.
A glider does NOT lose control when the tow rope breaks. It continues to glide and
the pilot has full control. The two aircraft are flying in formation, both flying
significantly above their stall speeds”.
1.18
Additional Information
1.18.1 Soaring Safaris Launching Procedures:
 Normal pre-flight cockpit checks, except that it is recommended to leave the
canopy open until the last moment.
 Radio check with tug, e.g. “Charlie Golf Yankee Papa Echo radio check”, “Papa
Echo Golf Yankee reading you fives”, “Golf Yankee fives also”, “Papa Echo call
take-up slack when ready”.
 Hook on cable. Release checks, if required, should be done before the tug
arrives.
 When ready to launch, shut the canopy, check that it is “all clear above and
behind”, ask for the wings to be levelled, and radio, e.g. “Golf Yankee take up
slack”. If your glider is ballasted, brief your wingman to make sure that the wings
are balanced. If they are not, dump water from the overweight wing before
commencing the launch.
 When the rope is about to tighten, radio, e.g. “Golf Yankee all out”.
 Usual techniques and precautions apply. If a wing drops and cannot be
immediately recovered, then release the rope. (A few minutes' delayed launch is
much better than an uncontrolled ground loop.) In a crosswind, most gliders are
more controllable if the initial ground run is made with airbrakes open – but do
remember to shut them!
1.18.2 Soaring Safaris Aerotow Procedure:
 Once rolling, the tug pilot will call on the airfield frequency advising of the takeoff, checking for any conflicting traffic.
 Using the normal tow position.
Note: Methods of transition from ground roll to flight:
• Remain in low, close to ground flight and allow tug to climb out automatically
placing glider in low tow.
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• Fly above slipstream in high tow until a safe height is reached to transition into
low tow.
• Where low tow is not desirable: fly above slipstream in high tow with no
transition into low tow.
 After take-off the tug may make a gentle partial turn to the northeast of the airfield
before flying north to northwest or make a safety orbit to the east before going to
the northwest. This tow pattern goes over landable fields in the earliest part of the
launch and runways 28 tar, 18 grass or 27 grass are available in case of a
problem.
Note: If out of position:
• Use airbrakes to keep a taut rope.
• Flaps as a method to keep rope tight.
 The tug pilot will normally try and take the glider to a thermal and circle in it so
the glider can release while turning in lift.
 There is no set direction for the glider to turn off tow but please do not release
with the tow under excessive tension and give the tug a call to say that you are
off tow. If the tug has found a thermal and is turning in it, carry on turning in the
same direction after release.
 Standard emergency signals apply, that is, if the tug waggles its wings
vigorously, then the glider must release immediately, and if the tug waggles its
rudder the glider should check that the airbrakes are closed and locked. If the
glider pilot is unable to release from the tug and unable to contact the tug pilot by
radio, he should fly out to the left of the tug to attract the attention of the tug pilot.
1.18.3 Soaring Society of South Africa (SSSA) Cable Breaks Procedure:
1. Order of events as follows:
• Restore safe flight with sufficient airspeed
• Release cable
2. Decide on options available in the following order:

Land ahead

Perform 180 degree turn and land downwind

Perform an abbreviated circuit and land

Complete a normal, but lower circuit and land
3. Other options depending on circumstances:

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
1.19
Be careful of teaching airfield specific options.
Useful or Effective Investigation Techniques
1.19.1 None.
2.
ANALYSIS
2.1
Aircraft certification:
2.1.1 The aircraft involved in the accident was manufactured by South African registered
company Jonker Sailplanes. According to the manufacturer's information, the
aircraft with production designation JS 1C 21m was approved by the SACAA. A
type certificate (no. J15/12/550) to signify the airworthiness was issued during
February 2010. The type certificate is relevant because it shows that the aircraft
conformed to the design and manufacturing standards. It also signifies that the
aircraft was suitable for use in the utility category of airworthiness and safe flight
anywhere in the world.
2.1.2 The aircraft flight manual (AFM) includes all the information required for safe and
efficient operation. The AFM states that “the aircraft is a high-performance single-seat
sailplane of conventional layout with a T-tail. The design allows for two wingspan
configurations, the one being 18 m and the other 21 m. Both wings are fitted with a full span
flaperon and on the upper surface fitted are triple blade design airbrakes. The cockpit
section is designed to provide good crash safety features including a crumple zone in its
forward structure. It is also fitted with one small fixed tail wheel and a retractable sprung
main wheel in the bottom of its fuselage”.
2.1.3 The above certification information was investigated. The aim was to determine if all
regulatory requirements in this regard were complied with. The evidence was that
the aircraft type was fully compliant with its specifications.
2.2
Aircraft registration and airworthiness:
2.2.1 The accident aircraft (s/n 1C-056) was sold to JS 1 - ZM Partnership. The aircraft
was registered in South Africa in the name of its owners. When the aircraft was
registered all the required details were duly entered onto the South African Civil
Aircraft Register (SACAR). The owners were then issued with a certificate of
registration (CoR). The certificate of registration (CoR) signifies that the aircraft
could fly to, from and within the Republic. The nationality and registration marks
allocated to it were “ZS-GBF”. The nationality and registration marks were found
displayed appropriately on the aircraft as required by applicable regulations.
2.2.2 Another mark, ZM, was found on both sides of the vertical stabiliser of the T-tail.
The manufacturer was requested to explain the reason for the ZM marks on the tail
section and to show evidence whether or not the marks were approved by the
SACAA. They responded to the two questions as follows. The marks are not
unusual in the gliding operations. The marks are used by operators as identification
during gliding or soaring competitions. Research was done to verify the information
of the manufacturer.
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2.2.3 The research showed that in other cases “numbers instead of letters” are displayed
on the vertical stabiliser. The manufacturer indicated that the aircraft owners made
the decision to use the numbers or letters. All the manufacturer did was to ensure
that the marks were displayed as per the specifications. The specifications used in
this regard are the same as the requirements of the nationality and registration
marks.
(i) However, the applicable regulations (Part 47) state that “No person shall place on
any South African registered aircraft any mark or symbol which modifies, confuses or
purports to be the nationality or registration mark allocated and displayed in
accordance with the specifications referred to in sub-regulation”. The SACAA
response on the matter was that “the allocation, display and location of registration
marks should be done according to SACATS 47. The SACAA is not aware and has not
approved the ZM painted on the aircraft”. The owners are responsible to submit an
application to the SACAA. Only once the application has been approved will the
owners be allowed to display the ZM marks.
(ii) The SACAA indicated that they had no record of ever receiving such an
application or issued an approval to either Jonker Sailplanes and/or JS1- ZM
Partnership in this regard. There are several gliders which operate in the
Republic and have similar types of special marks displayed on them. The
SACAA has to ensure that the glider operators/owners correct the identified
situation. All the gliders having this type of special numbers or letters displayed
on them should be immediately approved as per the applicable regulations.
2.2.3 After the owner (JS1 – ZM Partnership) had been issued with the aircraft registration
certificate (CoR), the owner was required to prove that the aircraft was airworthy.
The aircraft had to be maintained in accordance with applicable regulations and
certificate of release to service (CRS) had to be issued:
(i) The investigation determined that the manufacturer was responsible to carry out
maintenance on the aircraft. The maintenance records show that the aircraft was
properly maintained and no anomalies were identified. After the maintenance had
been completed and a certificate of release to service (CRS) had been issued,
the aircraft was certified airworthy and fit for flight.
(ii) The aircraft records show that it was operated for a period of four months from
August 2013 to January 2014. It accumulated a total of 198 hours' flying time.
The information indicated that the aircraft was still new. The aircraft history did
not show any evidence of defects, system malfunctions, incidents or accidents
identified during maintenance and by the pilot which could have influenced its
operation negatively.
2.2.4 Now that the aircraft was issued with a valid certificate of registration (CoR) and
certificate of release to service (CRS), the owner could submit an application to
have the certificate of airworthiness (CoA) issued. The certificate of airworthiness
(CoA) could only be issued after the aircraft had been subjected to an inspection by
the SACAA. The purpose of the inspection was for the SACAA to establish whether
or not the aircraft was airworthy. After the inspection had been completed, the
aircraft was found to be airworthy and a standard certificate of airworthiness (CoA)
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was issued.
(i) The CoA indicated that the aircraft was to be used in the non-commercial
operation category, Part 91. This part requires that the aircraft be operated in
the general aviation and operating flight rules. The aircraft could participate in
all civil aviation operations other than scheduled or non-scheduled flights not for
remuneration. The process of the issuance of the certificate of airworthiness
(CoA) was also investigated and no anomaly was identified.
(ii) Now that the owner had the aircraft documents (i.e. certificates of registration
CoR, certificate of release to service CRS, certificate of airworthiness CoA and
others), they could go ahead to operate the aircraft in the general aviation (GA)
category. However, the evidence was that the owner decided to operate the
aircraft in the aviation recreation operation category, Part 149.
2.3 Aircraft operations and management
2.3.1 As indicated above, the aircraft was going to be operated in aviation recreation
operation category, Part 149, by one of the sport and recreation aviation
organisations, Soaring Safaris, affiliated to the Soaring Society of South Africa
(SSSA).
(i) In order to ensure that the requirements of Part 149 are complied with and
oversight is carried out over SSSA and Soaring Safaris, the SACAA delegated
its powers to the Recreation Aviation Administration of South Africa (RAASA).
This designated body was charged with the responsibility to manage, control
and oversee the aviation recreation organisations' sport and recreation aviation
activities, including the issuing of all related licences and authorities to fly.
(ii) The method of compliance was investigated with the aim to determine whether
or not the aircraft was operated satisfactorily under the supervision of RAASA.
The SACAA was requested to assist in providing a copy of RAASA’s delegation
of authority. The SACAA was also requested to provide a copy of RAASA’s
terms of reference (i.e. memorandum of agreement (MOA) and service level
agreement SLA) in order to determine whether RAASA had legitimate powers to
carry out the oversight responsibility over the sport and recreation aviation
organisations' activities. All the documents relevant to RAASA’s designation
were checked for compliance and no anomaly was identified.
2.3.2 The evidence was that RAASA approved the Soaring Society of South Africa
(SSSA) and issued it with an aviation recreation organisation (ARO) approval
certificate. Upon request, RAASA submitted a copy of SSSA’s approval certificate
(no. ARO/003), which authorised the SSSA to “oversee and develop the safe operation
of its affiliated members and continuously evaluate compliance with the conditions of its
approved MOP, CAR’s and Technical Standards as determined by RAASA”. Furthermore,
the validity of the certificate was subject to regular reviews and audits being carried
out by RAASA.
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2.3.3 According to the SSSA ARO certificate, it was approved to be responsible for
gliding and soaring aviation recreation activities in South Africa. The SSSA's
responsibility is widely covered in its MOP, which contains all the operational
governance and compliance operating procedures. The MOP is made available to
all affiliated members. The MOP states that “for safety regulations purpose the affiliated
members are required to operate to the standards defined in the MOP. They may specialise
the procedures for their own unique operational context, provided that the variances are
documented in the club's specific MOPs and approved by SSSA”. The MOP was
checked in the investigation and no anomalies were identified.
2.3.4 The investigation found that SSSA has a total of 21 affiliated members. The
operator of the glider in question (Soaring Safaris) was also an affiliated member of
SSSA. According to the SSSA MOP, the affiliated members ordinarily are
“administered as autonomous organisations, clubs (societies) or Section 21 companies and
conducting gliding operations with their own facilities and resources”. Based on available
information, Soaring Safaris conducted its operations as follows:
(i) Soaring Safaris has been administered as an autonomous organisation involved
in gliding and soaring operations for approximately fourteen years since 2002. On
the business side, the company receives foreign glider pilots from different parts
of the world visiting South Africa. The pilots are sometimes accompanied by their
families. They arrive in the country during Soaring Safaris' open season, which is
from November to mid-February. Their business model allows for the visiting
pilots to hire and fly the different types of gliders in the fleet. Other services
include the use of their club facilities. All operations are carried out at New
Tempe Airport (FATP) in Bloemfontein.
(ii) Soaring Safaris was requested to submit a copy of its membership certificate and
MOP for verification. A response was received from their Chairman stating that
“memberships were implicit in SSSA MOP” and “we don’t have an individual MOP, the
SSSA MOP is a generic document that applies to all clubs”. They then submitted a
copy of the SSSA MOP, but no membership certificate. This suggested that they
did not have in their possession either one of the two documents readily
available. This issue was taken up with SSSA, which forwarded a copy of the
certificate. The MOP and membership are important for the following reasons:
 The MOP is regarded as the “blueprint” of an organisation. It is unique in that it
describes the operational procedures of an organisation. As we know, every
organisation operates differently, depending greatly on their size, scope and
structure. It is therefore advisable that every organisation should have its own
MOP which is tailor-made for its operation. This is precisely the reason why
AROs are required to have an MOP, which serves to demonstrate the means and
methods by which the SSSA will ensure compliance with the requirements
prescribed in Part 149. After a thorough review conducted by RAASA, the MOP
is then approved.
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 The SSSA MOP states that “affiliates may specialise the approved operational
procedures for their unique operational context, provided that such variance is
documented in a club specific operational manual approved by the SSSA Exco”. This is
the reason why the decision of affiliated members to use the generic SSSA MOP
as their own is questionable. It goes without saying that affiliated members
should have their own club-specific operational MOP approved by SSSA. If they
continue to use SSSA MOP, it may result in a situation of misrepresentation due
to variations in operational requirements.
 The affiliated membership certificate is also very important because it outlines the
scope of approval of every member. All operators in the civil aviation environment
know they should have some sort of an approval certificate issued before they
can continue to operate. Soaring Safaris could not provide an approval certificate
when requested. Only after the matter was brought to the attention of SSSA did
they submit a copy (no. 30).
 When the certificate was reviewed, a problem was found, namely that the
certificate was issued in the name of the Chairman of Soaring Safaris. What this
means is that the Chairman assumes the position of the affiliated member, not
Soaring Safaris. Furthermore, the certificate was printed on the letterhead of the
Aero Club of South Africa and stated that “this is a certificate of SSSA and Aero Club
of South Africa”. The expectation was that the certificate should read “this is a
certificate of SSSA and RAASA”. Information was included to show that the
affiliated member was Soaring Safaris. The certificate did not specify the aviation
recreation activities which Soaring Safaris was entitled to undertake.
2.3.5 The SSSA MOP instructs “affiliates to take responsibility for their gliding operations and
to conduct such operations with appropriate supervision”. The evidence found shows
that Soaring Safaris hosted a total of 9 visiting foreign gliding pilots in South Africa
during their open gliding season, which is from November 2013 to February 2014.
As evidenced by the requests for certificates of recognition of foreign gliding pilot
licences, the foreign gliding pilots were all from different countries.
(i)
The system of applying for certificates of recognition of foreign gliding pilot
licences (GPL) was reviewed in the investigation. According to the
regulation, the privilege to approve or issue licences has been delegated to
RAASA. The SSSA MOP confirms to its affiliated members that only RAASA
has this privilege. RAASA was then requested to provide evidence that they
had received the applications and approved them. RAASA’s response was
that they “ have no records and no information on file for the pilot. Thus, as
RAASA, they did not accept and would have been unable to process such a
document”. The issue was brought to the attention of Soaring Safaris, which
stated that “the foreign GPL recognition process is delegated by SSSA to specific
people at various gliding sites that have a lot of overseas visitors. The Chief Flying
Instructor (CFI) of Soaring Safaris has been delegated with the recognition
authority”. The CFI then continued to approve the recognition applications of
the pilots based on this delegation.
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(ii)
According to Part 68, the organisation designated for the purpose (which in
this case is RAASA) may recognise through validation a foreign pilot licence
and rating. By implication, RAASA first has to receive a recognition
application on the appropriate prescribed form. The SSSA MOP states that
“RAASA may recognise international gliding qualifications, and may validate these
to facilitate participation in South African soaring events, through the appointment of
the SSSA as a single point of contact who delegates the functions as is required”.
(iii)
2.4
RAASA was quite clear in its response, stating that they had not accepted
and would have been unable to process the application, as no record existed
that such was sent. The response of RAASA shows that the function was
never sub-delegated to SSSA, as evidenced by its scope of approval. Also,
why else would RAASA say they had not received, accepted and/or
processed the foreign pilot’s applications which had allegedly been submitted
on 7 January 2014? The evidence is that the CFI was authorising the
validations of their visiting foreign pilots himself for years without any
question.
Human Performance
2.4.1 According to Soaring Safaris, all the visiting foreign pilots’ licences were
appropriately recognised and validated. Based on the validation being approved,
the pilot was permitted to fly the South African registered aircraft. The pilot's
qualifications and experience were investigated to determine his competency:
(i) The evidence indicated that he came from Norway. He was the PIC of the
accident aircraft and sole occupant. He had a very impressive and impeccable
résumé which showed a record of extensive flying experience. He served in the
Royal Norwegian Air Force, where he flew the F-16 aircraft. He held a valid
Norwegian civilian glider pilot licence (GPL) listing a number of different types of
gliders and a long list of ratings. He had logged a total of 1708 hours' flight time
when he arrived in South Africa.
(ii) He started his flying programme with Soaring Safaris on 4 January 2014 until 20
January 2014. Based on the pilot’s flying record, it shows that he flew a total of
16 days. There were two days on 6th and 19th of January 2014 which he did not
fly. He accumulated a total of 58,39 hours' flying time. A calculation was carried
out to determine the average flying time per day over the period. The average
time was 3,6 hours, which is fairly low; however, on certain days (10 January to
14 January and again on 17 January 2014) he flew between 5 to 6,5 hours
continuously each day. The reason why this issue of flight time is highlighted is
the possibility that he suffered from fatigue.
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(iii) For this reason, it was deemed important to enquire from Soaring Safaris about
gliders' flight duty time requirements. The response was “there are no duty time
restrictions for recreational gliding”. This literally means that glider pilots flying
Soaring Safaris aircraft have “carte blanche” when it comes to flight duty times.
The regulations were checked in this regard. Part 91 states that “pilots who are not
subject to an approved flight time and duty period scheme shall fly 10 hours within a 24
hour period”, which contradicts the statement made by Soaring Safaris. The
regulation quoted was used to determine whether or not the flight time flown
would have contributed to fatigue. A calculation was carried out to assess the
relationship between the actual flying times and the duty time limit. It was
determined that the pilot was at the most about 3 to 4 hours below the duty time
limit of 10 hours within a 24-hour period.
 The record of flying times shows that his earliest take-off times were between
11:00 to 11:30 in the morning and that he returned at about 17:30 to 18:30 in the
afternoon. Every day when he flew and landed at the identified times, the flight
duration was about 05:30 to 06:30 hours. This way he managed to control his
duty time correctly. Whenever he landed a bit late on a particular day, he would
also take off later the next morning at about 12:00 – 13:00 and landed earlier, at
about 17:00.
(v) However, the important factor in connection with the fatigue issue is captured in
the regulation stating “no person shall act as a crew member of an aircraft if the he/she
knows or suspects that he or she is suffering from or, having due regard to the
circumstances of the flight to be undertaken, is likely to suffer from fatigue to such an
extent that it may endanger the safety of the aircraft or its occupants”. Here the
emphasis is on “he/she knows or suspects”, which places the responsibility on the
pilot to determine and take the necessary steps to ensure safety.
(vi) There were no complications relating to the pilot health and/or wellness which
could have influenced his performance. He had a valid unrestricted aviation
medical certificate. The pilot was unfortunately fatally injured in the accident. His
body was recovered from the accident site by the State Province Forensic
Pathology Services to carry out a post-mortem medical examination. The postmortem medical examination report concluded that the cause of the death was
due to multiple injuries sustained. The State Province Forensic Pathology
Services also collected specimens for the purpose of conducting toxicological
analysis. At the time when the investigation was completed, the toxicology results
were not yet available. Should the toxicology results necessitate it, re-opening of
the report will be decided by the investigating authority.
(vii) On the day of the accident the visiting foreign glider pilot attended the briefing at
about 10:00. At about 11:25, the conditions became favourable and he got ready
to fly. He was seen at the glider aircraft at about 12:00 noon doing a pre-flight
inspection. After the pre-flight had been completed, the tug plane had not yet
arrived. He waited next to the aircraft as he was next on the list to be launched by
the tug plane with registration ZS-CGN.
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2.4.2 The aviation qualifications and experience of the tug pilot were also investigated to
determine his level of competency.
(i) The evidence found shows that he was holding two positions (chairman and CFI)
at Soaring Safaris. As chairman, he was accountable for the gliding operations
and as CFI he was responsible for regulatory compliance. He was the PIC of the
tug plane on the day of the accident. His résumé was as impeccable as the
visiting foreign glider pilot's. He had extensive flying experience of about 1673
hours (PIC 1590 hours) on powered aircraft and about 6028 hours on gliders. He
had a valid PPL and GPL with a list of different types of aircraft endorsed on
them. He also had a list of other ratings on both licences. All these qualifications
and experience easily distinguish him as being fully competent to undertake this
operation.
(ii) No issues relating to his health and/or wellness were identified which could have
influenced his performance. He had a valid unrestricted aviation medical
certificate.
(iii) He held a briefing with the visiting foreign glider pilots at about 10:00 on the
morning of the accident. They started launching the first couple of gliders at
11:25 that morning. Soaring Safaris has two tugs (ZS-CGY and ZS-CGN), both
Cessna 182 aircraft. He was flying the aircraft with registration marks ZS-CGN on
the day. The launch time of the accident aircraft was planned for about 12:20. He
landed the tug plane just after 12:00 noon to launch the accident aircraft next.
When he arrived, the visiting foreign glider pilot was already waiting at the
airfield.
2.4.3 There were two ground handling personnel present to help to prepare the accident
aircraft for the launch. The two handlers were found to be competent and well
experienced in executing their activities. One was installing the tow line and the
other was doing the wing runner job to keep the aircraft level to the ground. No
anomaly was identified as regards the work done by both ground handlers, which
was limited to the identified activities.
2.5 Witnesses information
2.5.1 There were three witnesses who submitted statements in the investigation. The
witnesses played a very important role in the investigation, as their observations
helped to establish what happened.
 The information obtained from one of the witnesses shows that the accident pilot
received a flight briefing at 10:00. In the flight briefings they normally discuss
meteorological, operational and safety requirements relevant to the flight. After
the briefing, weather considerations did not allow them to proceed with gliding
operations. They had to wait for an hour and a half, till 11:25, when the weather
became favourable.
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 According to the witnesses' statements, Soaring Safaris used two Cessna 182
aircraft (ZS-CGN and ZS-CGY) as tugs on the day. According to the schedule,
the accident aircraft was next to fly at 12:20. The pilot started his pre-flight
inspection at about 12:00 noon. By the time he finished the pre-flight inspection,
the tug had not yet arrived. While he was waiting, he got engaged in a
conversation with one of the witnesses (another glider pilot). The witness stated
that the conversation was about the instrumentation fitted in the accident aircraft.
The witness took an interest in the accident aircraft because he was going to fly a
similar type. The conversation did not last long before the tug arrived.
 When the tug pilot arrived, it got into position in front of the accident aircraft for
the hook-up. According to the SSSA MOP, the procedure requires that “the total
length of the combination from the nose of the tug to the tail of the glider shall not
exceed 150 m in flight”. Also, the tow line should be “60 m long and not shorter than
50 m”. Information provided by Soaring Safaris was that the tow line used was
actually 55 m long. As soon as the tug was in position in front of the glider, two
ground handlers prepared the glider for the launch.
 The two ground handlers were helping each other. One handler hooked up the
tow line. The other was holding the left wing up to ensure that both wings were
level with the ground. The pilot was sitting inside the aircraft waiting for the
launch. The tow pilot was sitting in the tug waiting for the hook-up to be
completed. According to the tug pilot: “prior to starting the take-off, radio
communications were checked between the two aircraft. The pilot instructions were clear
and precise”. Nothing else was required because “factors affecting the take-off run”
had already been discussed during the flight briefing. The tug pilot also indicated
that “generally there is no communication between the glider and tug pilots during the
course of the tow, except the instructions to start the tow and a message from the glider
pilot to say that he/she has released”.
 A normal take-off then followed and lift-off occurred just at the end of the paved
section of the runway. The witness who spoke to the accident pilot earlier said he
watched the aircraft taking off. He stated that during the take-off run he saw one
of the ground handlers “running with the left wing” to keep the glider straight. He
saw that the glider had its flaps on setting #1 (deflection -3˚). The take-off run
was normal and routine. He watched the take-off because he wanted to see at
which point the pilot would change the flaps from setting #1 to a higher setting
during the take-off. The lift-off also was routine, with the wings level when the
aircraft was leaving the ground.
 The tug pilot indicated that “once airborne he held the tug down to allow the airspeed
to build up to a speed of 85 mph/74 kts before initiating a gentle climb out”. The AFM
states that the maximum aerotow speed of 180 km/h or 97 kts should not to be
exceeded. The tug pilot further stated that “lift-off occurred just at the end of the
paved section of the runway”. The end of the paved section was determined to be
after about 500 m from the threshold. The runway is approximately 800 m long
(500 m paved and 300 m grass/gravel). When the aircraft was “at the 500 m point,
the speed was about 60 mph/52 kts”. In order to do a safe climb, the speed had to
be approximately 85 mph or 74 kts, by which time they would have reached the
end of the runway. To make up for the speed shortfall he used most of the
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remaining 300 m to accelerate and achieve the required airspeed before initiating
a gentle climb.
 The tug pilot indicated that “I was towing a heavily ballasted glider in relatively hot
conditions”. The issue of the glider being “heavily ballasted” was investigated by
way of calculating the weight and balance. According to the AFM, a glider with 21
m wingspan has an empty weight of 728 lbs/330 kg and the maximum weight is
1587 lbs/720 kg. The weight information is important because a proper weight
and balance calculation will ensure safe operation. If the indicated weight and
balance limits are exceeded, the pilot, aircraft and public which will be put at risk.
The flight characteristics of an aircraft of which the weight and balance are out of
limits may be adversely affected by the extreme forward or aft centre of gravity.
This is especially important during take-off, as the rolling distance required will
increase and climb performance will decrease.
 The empty and maximum weight information of the AFM conflicted with the
SACAA-approved weight and balance certificate information, which showed that
the empty mass was 755,3lbs/342,6 kg and the maximum mass was 1322,77
lbs/600 kg. The investigation calculation revealed that the aircraft's total weight
was approximately 1474,89 lbs/669,0 kg, i.e. the glider was overweight by
152,12lbs/69 kg. The manufacturer also did his own calculation and determined
that the total weight was 1463,9 lbs/664 kg. However, they concluded that “the
mass during take-off was below the allowable MAUW”. The manufacturer's
conclusion was right, but only if the calculation is based on using AFM empty and
maximum weight information. This conclusion becomes incorrect if the
calculation is based on SACAA-approved empty and maximum weight
information. Based on the latter, the glider was 141,1 lbs/64 kg overweight. It
should be noted that the overweight glider will perform better during cruising, but
poorly during take-off and climbing.
 Consequently, the overweight of a glider may have had an effect on the glider
whereby the increased inertia in the wings caused an increased adverse yaw
effects followed by a dive. Because of the excess weight, the CG position at
which the glider was in balance was also calculated. The calculation determined
that the CG was at 379,5 mm (±5 mm behind the allowable position). The
conclusion was that the glider pilot experienced an aft CG condition, which
probably affected the pitch stability of the aircraft. Pitch instability will tend to
make the glider dive or climb progressively, i.e. to enter into a very steep dive or
climb or stall.
 The tug pilot indicated that he initiated the gentle climb without allowing the
airspeed to decay. When he achieved a positive rate of climb, he entered into a
“gentle turn 5˚-10˚ to the left”. The SSSA MOP indicates that “[u]nless otherwise
requested, or if an experienced Pilot in glider, make average rate 1 turns”. A rate one
turn or standard rate of turn refers to the angle of bank (AoB) which the aircraft
makes when turning. It is defined as “heading changes about 3˚ per second”.
Nonetheless, it was established that the airspeed was 85 mph/ 74 kts when the
tug turned left. In order to determine the rate one turn angle, a mathematical
formula was used. The conclusion reached was that the angle of bank (AoB)
required if a rate one turn was carried should have been approximately 13.7˚ to
comply with the MOP.
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 The MOP states that “For the purposes of avoiding collision the tug and glider shall be
regarded as a single aircraft under the command of the tug-Pilot”. This means it is
critical that both pilots operate as one during the launch. Hence the procedural
requirement that the “The tug-Pilot is responsible for ensuring prior to take-off that
adequate signals have been agreed and can be made between the Pilots, and between
the Pilots and ground crews. Such signals will include emergency signals ordering the
glider Pilot to release, or informing the tug-Pilot that the glider cannot be released. Such
signals shall not be dependent solely on radio contact”. As indicated before, the
above was probably mentioned during the briefing and/or prior to take-off.
 The tow pilot further stated that his intention was to pass the hill and the church
building located on the extended centre line of the runway. He made the left turn
to enter a track aimed at avoiding the high ground (hill) and to direct the aircraft
into the wind.

In order to verify the high ground issue brought up by the pilot, the
investigation calculated that the runway used had a down gradient of 1,3%
(difference in elevation from the beginning to the end of the runway). The
calculation determined that from the end of the runway to the church building
on the hill, there was an up gradient of 0,7% (difference in elevation from the
end of runway to the tip of the hill). This is proof that they were flying toward
high ground, hence the action taken to avoid it.

The information regarding turning the aircraft into the wind was also
investigated. As indicated before, the take-off was from Runway 360 in a
northerly direction, turning to the left 13,7˚ AoB heading on new track into a
north-westerly direction (346,3˚). However, it seems that the aircraft was still
going to turn some more, probably until heading straight into the wind.
According to the METAR information the wind direction was 330˚, which
means that the tug pilot made the right decision to turn left to head into the
wind.
 The tug pilot also stated that there were other reasons for the left turn, such as
the succession of open, safe landing fields on that route in the event of an
emergency; wind conditions; thermal activity; activities on other runways at the
airfield and, most importantly, the weight of the aircraft being towed.
2.5.2 The tug pilot indicated that “just after the two aircraft had passed the hill, he felt a severe
jerk on the tow line pulling the tail of the tug plane to the right”. According to the SSSA
MOP, it states that “the tow positions should be established between the tug and glider
pilots before take-off”. The investigation established that the glider pilot had received
a briefing prior to the flight. The procedure to position the glider correctly is that the
pilot must point the nose of the aircraft to the outside wingtip of the tug plane during
the turn. However, the evidence found shows that the glider ended up moving out of
position during the left turn manoeuvre.
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 As indicated by the tug pilot, “the tail of the tug/towplane was pulled to the right”. It
shows that the glider moved out of position to the right side of the tug plane. It is
assumed that the rope line probably made a bow just as the glider moved out of
position. The result was that the tow line then quickly pulled taut, which caused
the severe jerk felt subsequently. The severe jerk was probably caused by two
forces pulling in opposite directions: one force being that of the powered tug
plane pulling to the left side, the other force being the tow line pulling to the right
due to the glider being out of position. This is probably the reason why the tug
pilot said he “looked in his rear view mirror to see if he could locate the position of the
glider”. However, before he could locate the glider another severe jerk was felt.
This second severe jerk means that the same scenario explained above occurred
for the second time in a row.
 All the above information ties in correctly with the information provided by witness
#4, who stated that during the take-off he saw the position of the glider being
slightly higher than the tug plane. This flight manoeuvre is called a high tow
position. He then saw the tug/towplane turning left with the glider continuing
straight ahead. This was probably the time when the severe jerks were felt on the
tug plane and also the reason why the tug pilot could not see the glider in his rear
view mirror; it was out of position, as previously indicated. He probably saw the
tug plane flying away from the glider at the time the tow line broke and the tug
plane started to accelerate.

The observations of witness #3 also tied in very well with those of the other
witnesses. However, there was one thing that stood out which needed to be
clarified. He said that “the glider began swaying/banking left and right and could not
deduce whether it was done intentionally by the glider pilot or due to thermal activity or
propeller wash of the tug plane or loss of control”. All the factors which the witness
had identified were investigated.
 The issue of the glider “swaying/banking left to right” could be associated with
the glider pilot making use of launching signals to draw the attention of the tug
pilot. It means that the glider pilot was most probably showing one of two
signals, or both, to communicate his situation to the tow pilot: one signal being
that the glider was yawed repeatedly with the intention to relay the message
that the tow pilot should decrease the towing speed, the other signal being that
he was probably rocking the wings of the glider repeatedly to relay the
message that the tow pilot should increase the tow speed. If it was indeed the
case that these were messages sent by the pilot and the tow pilot did not see
them immediately, the situation would simply be unfortunate – that the tug
pilot's failure to respond to either of the two signals created a very hazardous
condition for both aircraft. Whether or not the glider pilot was in fact signalling
cannot be proven.
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Note: According to the aircraft manufacture, stating that “the bullet above implies that
visual signals were used. This is not the case in South Africa, as it was never
implemented or trained. It is regarded as dangerous with modern gliders. Also, visual
signals are not used for aerotowing. This is however used in winch launches in South
Africa”.
 It is also possible that the thermal activity and/or propeller wash may have had an
effect on the glider. The book Aerotowing Gliders: A guide to towing gliders, with
an emphasis on safety, states that “propeller wash can contribute to a glider dropping
a wing and subsequent ground-loop, which in turn will affect the tug”. Based on the
direction of the propeller rotation, the effect will be that “the higher airspeed of the
propeller slipstream increases the lift and AoA of the left wing and has the opposite
effect on the right as well as simply pushing the left wing up and forcing the right one
down”. In a similar way, the effect of thermal activity (“updrafts and downdrafts”) will
result in either a lift or sink attitude. Hence it is important that the glider pilot must
constantly be aware of these threats.
 The issue of the pilot “losing control” was investigated. The document NASA:
Aircraft Accident Prevention Loss of Control Analysis states that “loss of control is
generally associated with flight outside of the normal flight envelope, with nonlinear
influences, and with an inability of the pilot to control the aircraft”. There was no
evidence that any of these happened. Neither is there any evidence of pilot error.
 There was no evidence of the flight controls not functioning correctly. The Jonker
Sailplanes wreckage investigation report states that “the control system in the
cockpit control box suffered severe impact damage. No evidence of failure prior to
impact was found. The control system in the central fuselage suffered impact damage,
but no defects were observed. The control system in the wings suffered severe impact
damage. No evidence was found that the control system failed prior to impact”. It is
alleged that the swaying continued until the moment the tow line broke.
2.5.3 The tow pilot indicated that immediately after the second severe jerk was felt the tug
plane started to accelerate. The observation was that the glider pilot had released
the tow line or the tow line broke. The evidence was that the tow line broke,
resulting in the two aircraft separating from each other in flight. The broken tow line
was found at the location of the accident next to the main wreckage. The evidence
was that the tow line broke at the attachment at the tug end. The tow line was
recovered from the accident site and taken to a service provider (CrashLAb) for
examination and testing. The test results were as follows:
 During the take-off the tow line failed at the position of the TOST ring attachment
at the tug aircraft end.
 The tow line in question conforms to a typical 3 strand “2” construction
manufactured from multifilament polypropylene. The TOST tow line release
mechanism was used on both the tug and the glider aircraft.
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 The visual investigation revealed a fracture at the position of the TOST ring (tug
aircraft end). Closer inspection of the tow line spliced around the glider end
revealed extensive scuffing damage as well as fractured tow line yarn filaments
at various positions along the tow line length. The installed TOST ring revealed
extensive wear damage as well as abrasive wear on the tow line protective
sheath.
 CrashLAB then concluded their inspection/examination stating that “ the primary
causational factor in the failure of the tow line is the damages inflicted unto the tow line
at the position of the TOTS ring at the tug aircraft end which resulted in the ultimate
failure thereof during the take-off phase of the launch”.
2.5.4 The investigation determined that the tow line length was 55 m from TOST ring to
ring. The recommended minimum length is 50 m; the extra 5 m allows for resplicing as required. Whenever any of the tow lines happens to get worn where it is
attached to the TOST rings, the affected lines will be respliced on an “on condition”
basis. The tow line used is a 10 mm diameter polypropylene rope with TOST ring
attachments as per the manufacturer's specification. The tow line's maximum
strength is twice the maximum certificated operating weight. Specification – B.
Force = 1425 kgf, which is twice the glider's maximum certificated operating weight.
The mass and balance calculation above shows that the glider was overweight by
69 kg. The tow line was subjected to three break load tests. The test results show
that when loads were applied, the tow line failed on the yarns. The variation in
fracture geometrics between the tested samples and accident samples shows that a
large fraction of the rope at the accident break point did not fail under a singular
overload, but failed over an undeterminable period of operation.
 According to Soaring Safaris, they “start the gliding season always with new
towropes/lines. It is the responsibility of the tug aircraft pilot to carry out inspections of
the towropes/lines every day. It is a visual inspection which includes checking of towrope
coupling, ring pair for weak link and excessive wear, release mechanism for excessive
dirt and improper functioning”. However, when the tug pilot was asked whether or
not he could provide any proof that he or someone else did carry out the tow line
inspection before take-off, his response was “I don't keep a record of who does this
inspection. The ropes are inspected after the day's launching so that if there is damage it
can be repaired before the next day flying”. The tow line was allegedly new at the
beginning of November, and if the tow line was ever found defective for any
reason and needed to be respliced, this would be done when wear was seen. He
and a couple of visitors who knew how to do the resplicing would do it.

Apparently, they had never had a tow line failure in normal operation. The tow
line that failed did so when the glider moved out of position and put an abnormal
load on the rope.
2.5.5 The tug pilot said that after the tow line broke, he flew straight ahead, maintaining
his heading to clear the area and not to get in the way of the glider. He thought that
with the tow line broken, the glider was in free flight and looking for place to land.
Witness #3 confirmed seeing the tug plane maintaining its heading and the glider
continuing to climb and entering into a sharp left turn. The glider then entered a dive
attitude with the nose pointing down until it impacted the ground. Witness #4
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estimated the left turn angle to be approximately 45˚ AoB, but on the left side of the
tug plane.
 The wreckage investigation shows that after the tow line broke the glider yawed
to the left side, rolled into a steep nose down attitude considered to be a dive
straight toward the ground. The wreckage examination shows that the right wing
hit the ground first when impacting the ground. It is also evident that the right
wing tip hit the ground before the nose and/or left wing, as the right wing was
found completely broken. The impact marks on the ground caused by the right
wing were much more pronounced than those of the left wing. After the right side
wing tip impacted the ground, the leading edge struck the ground, causing that
wing to be destroyed.
2.5.6 It is believed that the combination of the following factors: low altitude, weight and
balance, tow speed, pilot’s experience on type and his failure to maintain position
behind the tow plane may have contributed heavily in the accident. Due to these
factors, especially the low altitude, no recovery was possible. The event of the tow
line breaking further exacerbated the situation in that the glider entered a yaw over
to the left and rolled into a steep nose-down attitude in a spiral dive straight to the
ground.
3.
CONCLUSION
3.1
Findings
3.1.2 The SACAA delegated the responsibility over aviation sport and recreational
operations to a designated body, namely RAASA.
3.1.2 The glider wreckage was recovered from the accident site to the facility of the
manufacturer (Jonker Sailplanes (Pty) Ltd.). The manufacturer assisted the
investigation team with reconstruction and examination of the wreckage. The
conclusion was that all the parts and components were in good serviceable
condition prior to the flight and the damage sustained was the result of the ground
impact.
3.1.3 The accident pilot was a Norwegian national hosted by a designated organisation
(Soaring Safari Club), a member of Soaring Society of South Africa for the duration
of the gliding open season in Bloemfontein. He had been in the country from
November 2013, when the gliding season started.
3.1.4 The accident pilot had in his possession a valid Norwegian gliding sporting licence
#45642 and a Class 2 aviation medical certificate with no restrictions. He had 1100
hours' gliding experience. He had complied with domestic rules by submitting to
RAASA an application to issue a certificate of recognition of his foreign glider pilot’s
licence. The application was accepted, approved and issued to him.
3.1.5 The pilot’s experience on the JS-1C type was determined to be 8.05 hours and 3
take-off.
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3.1.6 The pilot was the sole occupant on board of the glider.
3.1.7 The SACAR and CATS do not have any standards or requirements for tow line
strength.
3.1.8 The tow line showed evidence of extensive scuffing and fractured rope yarn
filaments at the TOST ring and at various positions along the rope length caused
over an undetermined period of operation.
3.1.9 The TOST ring also showed evidence of extensive abrasive wear damage on the
rope protective sheath.
3.1.10 The general condition of the tow line, its age (both since manufacturing and
operationally) and the TOST rings were questionable.
3.1.11 The weight and balance calculation of the glider revealed that the maximum mass
was exceeded during the take-off, which had an impact on the tensile stress of the
tow line.
3.1.12 The overweight condition of the glider adversely affected the centre of gravity (CG)
position, moving it behind the allowable position, and the aft CG made the glider
more susceptible to pitching when exposed to the sudden first and second jerks.
3.1.13 The glider was flying straight and level in a high tow position behind the tug aircraft.
The tug aircraft banked to the left and experienced two consecutive significant and
excessive jerks on the tow line, causing the tug aircraft to yaw during take-off.
3.1.14 The glider did not reach sufficient height/altitude to maintain flight or make recovery
possible.
3.2
Probable cause/s
3.2.1 During aero tow operation, the glider inadvertently moved out of position, as a result
exposed the already frail tow rope to a sudden increase in tension due to the
excessive load causing it to break. The glider then yawed to the left side, rolled into
a steep nose down attitude considered to be a dive straight toward the ground.
4.
SAFETY RECOMMENDATIONS
4.1 None
5.
APPENDICES
5.1
Copy of the CrashLAB Investigation Report;
5.2
Copy of the Aircraft Manufacture Investigation Technical Report;
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Appendixes A: CrashLab Reports
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Appendices B: Aircraft Manufactures Draft Report
HISTORY OF FLIGHT
On January 20, 2014, 10h22 Zulu time, a Jonker Sailplanes model JS 1C-21 glider, ZS-GBF, collided
with terrain 2 miles North of New Tempe, Bloemfontein. The pilot was fatally injured during impact
with the ground and the glider was completely destroyed. The aircraft was registered to JS1-ZM
Partners and operated by the pilot under the supervision of Soaring Safaris Gliding Club. Visual
meteorological conditions prevailed for the flight, which was not operated on a flight plan. The flight
originated from New Tempe, Bloemfontein, at about 10h20 Zulu.
The tug pilot reported that while on aero tow and flying in a North-westerly direction at about 4800
feet above mean sea level (300 ft above ground level), he was alerted by a significant jerk on the tow
rope yawing his tow plane to the left. The jerk was followed by a second violent jerk, breaking the
tow rope. The tug pilot tried to contact the glider pilot immediately without success. The wreck glider
was observed by the tug pilot in a field below who alerted the rescue teams. The rescue teams
arrived at scene of the accident within 10 minutes.
PERSONNEL INFORMATION
The 53-year old pilot held a Norwegian glider pilot licence. The pilot reported having 1100 total flight
hours in gliders, including 8 hours in the accident glider. His most recent flight review was completed
on 18 January 2014 in a ASW27 glider. He was issued a Class 2 medical certificate with a no
restrictions on 18/07/2013.
The pilot weighed 85kg and a parachute weighing 6kg was worn during the accident flight.
On the day of the accident the pilot planned to break the Norwegian gliding record for a 500 km flight.
The flight was pre-declared on this LX9000 flight computer.
AIRCRAFT INFORMATION
The accident glider was a Jonker Sailplanes model JS-1C 21m, serial number 1C-056. It was a
single-seat high-performance sailplane, constructed mainly of composite materials. The glider was
manufactured in 2013 and was issued A Certificate of Airworthiness on 6 November 2013. The
airframe had accumulated 198 hours total time in-service at the time of the accident.
The aircraft was flown by various pilots the preceding week and no abnormalities were reported.
Other pilots flying the glider commented on the desirable handling qualities of the glider.
METEOROLOGICAL CONDITIONS
Weather conditions recorded by FABL, located about 5 nm south-east of the accident site, at 1000z,
were: wind from 330 degrees at 15 knots, visibility xxx miles, scattered clouds at 14000 feet AGL,
temperature 30 degrees Celsius, dew point xxx1 degree Celsius, and QNH 1035. The glider pilot
who conducted an aero-tow just preceding the accident flight reported heavy low level turbulence
during his aero-tow.
WRECKAGE AND IMPACT INFORMATION
The glider impacted on a flat sandy surface in rural area 2 miles North of New Tempe airport.
Examination of the glider on-scene revealed that wreck faced towards the east. The remains of the
cockpit were found on the point of impact with no evidence of skid marks. The wing frontal profile
was imprinted on the ground surface. From the imprints it is clear that the right wing was slightly
lower during impacted with the ground. No evidence of rotation of yawing prior to impact was found.
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The tow rope was still connected to the nose hook. The release cable connected to the release
hook is intact.
The cockpit was completely destroyed and the tail boom snapped off to the right at a point
approximately 2 meters from the leading edge of the vertical stabilizer. The landing gear was
found in its extended position. The flap locking plate indicated damage marks in the 4th position
from the front. Rudder pedals were found in the full forward position. The 5th notch from aft of
rudder pedal adjustment rod is damaged into an oval shape.
The trim was found in the full forward position after impact. No impact witness marks were
observed. The design is as such that the trim may move during high forward or down
accelerations.
The control system in the cockpit control box suffered severe impact damage. No evidence of
failure prior to impact was found.
The rod end connectors of flap, airbrake and landing gear were snapped off in the cockpit area.
The control system in the central fuselage suffered impact damaged, but no defects were
observed.
The instrument panel and instruments were destroyed. Parts of instruments were found 15m in
front of the wreck. Three GPS loggers were carried on-board. The remains of only one logger
were found. Physical damage to the internal SD card prevented data to be downloaded from this
logger. This data card was shipped to the instrument manufacturer to see if logged data is
retrievable.
The pilot had a Galaxy 7” tablet attached to the right hand side of the canopy mounted on a suction
cup.
The canopy and canopy frame was destroyed during impact. The jettison mechanism was found in
the closed position. No indications were found that Jettison mechanism was operated during
impact.
The wings were still attached to the fuselage and the 21m tips attached to the main wings. Both
wings were destroyed with high energy impact on their leading edges. Panels of the wing skin
forward of the spar were found 20 meters in front of the point of impact. Evidence of water was
found for the length of the wingspan, suggesting that the wing water tanks were filled. The skins of
both wings were separated from the main spar for most of the length. The spars of both wings
were broken in various areas. The right wing is completely separated approximately 3 meters from
the root. The impact marks on the ground caused by the right is more pronounced than that of the
left wing. The impact marks made by the wings shows an arc approximately 1.2 m out of the
plane. The airbrakes were found unlocked after impact. Witness marks on the airbrakes blades
indicates moving from the closed position to the open position whilst under a high forward
acceleration force.
The control system in the wings suffered severe impact damage. No evidence was found that the
control system failed prior to impact.
The empennage was intact, apart from the right half of the stabilizer that is snapped off. The
actuator driving the elevators shows positive connection to the elevator pushrod supported in the
tail boom. The rudder sustained damaged to the skin surface in line with the bottom hinge and
separated from the top hinge of the fin. The rudder cables, connected to the pedals were still
intact.
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Two water tanks are fitted in the vertical stabiliser. The non-expandable tank was set up to carry 4
litres of water.
OTHER INFORMATION
The weight and balance for the aircraft based on information available at a weight of 664kg with a
flying centre of gravity position of 379.5mm. The mass during take-off was below the allowable
MAUW but the CofG was 5mm behind the allowable position. This is based on the mass and
balance report, the mass of the pilot of 85 kg, 6 kg parachute, 180 l of water in the main tanks, 34 l
of water in the tail tank, 7.5l of water in the expendable tank, 4 l in the non-expendable tank and a
2kg O2 bottle. An aft CofG position makes the glider more pitch unstable, and may lead to less
controllable pitch up motions when a jerk on the tow rope is experienced.
INFORMATION SUPPLIED BY WITNESSES
The accident was observed by a power pilot from MidWest flight training school. He viewed the
accident from side angle. According to the witness he saw the glider in the high tow position behind
the tug. He kept observing the tow as the glider appeared to be noticeable higher than previously
towed gliders flying above the tug’s slip steam. The tow plane started a turn towards the left. The
glider continued on its course, not following the tow plane immediately. The glider subsequently
pitched up and banked steeply to the left. The bank angle was observed as a steep angle as the
witness could see a full view of the cockpit. The glider continued rolling left until facing vertically
down. The glider impacted with the ground facing almost vertically.
Draft accident report:
On January 20, 2014, about 10h22 Zulu time, a Jonker Sailplanes model JS 1C-21 glider, ZS-GBF,
was launched from runway 36, New Tempe, Bloemfontein. The pilot in command was from
Norwegian origin, planning a National record. The aircraft was fully loaded with water ballast in
both the main wing tanks, 21m tip tanks and expendable tail tank. Additionally 4 litres of water was
carried in the non-expendable tail tank, resulting in the centre of gravity to be behind the allowable
range.Strong turbulent conditions during the previous tows were reported, and density altitude
resulted in reduced climb performance.
At approximately 300ft AGL the tug pilot changed direction from North to Northwest. The glider was
observed in a position higher than normal and failed to maintain position behind the tug plane,
drifting relatively to the tug aircraft to the right. A sudden, but temporarily, increase in cable tension
on the out-of-position-glider caused the glider to suddenly yaw and roll to the left and pitch up,
resulting in the glider rapidly moving to the left. The roll angle at this stage was observed from the
ground to be approximately 90°. A severe second jerk of the rope resulted in the rope breaking
with the glider facing nose down and away from the tug aircraft. The glider maintained its steep
nose down attitude and collided with the ground at a very high speed, fatally injuring the pilot.
Primary factors leading to the accident:
The pilot failed to maintain position behind the tug when the tug changed course to the left. When
the glider got out-of-position, the pilot failed to release before getting in an uncontrollable situation.
When the glider was diving towards the ground, the pilot failed to pull out of the dive. No indication
of any pilot input or communication from the pilot was observed from the time the glider got initially
out of position.
Conclusion
During on Aerotow the glider got out of position. The tow rope broke under severe strain with the
glider facing vertically down. The pilot did not recover from the dive and impacted the ground. The
pilot failed to follow the tug aircraft turning to the right, and did not release when out of position and
did not pull out of the dive. This lack of action from the pilot indicates that the pilot was distracted
during the aero tow (e.g. the Galaxy falling down during tow), got out of position and lost control of
the situation, or that the pilot lost consciousness during the last phase of the flight.
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