Collision with terrain, VH-RDU Double Mountain

Aviation Occurrence Investigation AO-2011-110
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Collision with terrain, VH-RDU
Double Mountain, Queensland
8 September 2011
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Publication Date: November 2011
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Released in accordance with section
25 of the Transport Safety
Investigation Act 2003
that was located on a peak of Double Mountain
South (Figure 1).
At about 1140 Eastern Standard Time on
8 September 2011, a Eurocopter AS350BA Figure 1: Location of the accident site
helicopter, registered VH-RDU, with a pilot and two
passengers on board, collided with terrain on
approach to land at a helicopter landing site that
was located on a peak of Double Mountain South,
The pilot and front seat passenger were fatally
injured and the rear seat passenger received
serious injuries. The helicopter was substantially
damaged. There was no fire.
The investigation is continuing.
Accident site
The information contained in this preliminary
report is derived from initial investigation of the
occurrence. Readers are cautioned that there is
the possibility that new evidence may become
available that alters the circumstances as
depicted in the report.
History of the flight
At about 1140 Eastern Standard Time 1 on
8 September 2011, a Eurocopter AS350BA
helicopter, registered VH-RDU, with a pilot and two
passengers on board was conducting aerial work
operations under the visual flight rules in the
Shoalwater Bay military training area, Queensland
(Qld). The helicopter collided with terrain on
approach to land at a helicopter landing site (HLS)
Eastern Standard Time (EST) was Coordinated Universal
Time (UTC) + 10 hours.
The pilot and front seat passenger were fatally
injured and the rear seat passenger received
serious injuries. The helicopter was substantially
damaged. There was no fire.
Survivor’s description
The surviving passenger, who occupied the rear
left seat, reported that the pilot was preparing to
land after twice circling the helipad slowly to the
right, before making an approach from the
south-west. While hovering at a height of about
80 ft from the landing pad, the helicopter
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commenced a climb, and turned left in what the Aircraft information
passenger believed was a controlled manoeuvre
by the pilot.
The helicopter, serial number 2495, was a
The passenger stated that at that moment, the six-seat, single-engine helicopter that was
helicopter encountered a lifting ‘gust’ and started manufactured in France in 1991. In 1992, it was
to spin to the left, completing two full rotations. converted to an AS350BA, including by fitting
The helicopter’s nose dropped in what the wider chord main rotor blades and a tail rotor
passenger thought was an attempt by the pilot to servo that were also found in the twin-engine
regain control. The helicopter then began to AS355 helicopter. It was placed on the Australian
‘oscillate’, a manoeuvre that the passenger
demonstrated using a helicopter model as a steep register in August 2003.
nose-down attitude, with roll 2 and yaw 3 from side In August 2007, the helicopter’s Turbomeca
to side. The helicopter struck the tree canopy
model Arriel turbine engine was replaced by a
before colliding with the ground, inverted.
Honeywell model LTS101-600-A3A turbine engine.
The passenger reported that he was able to cut That modification was carried out in accordance
himself free from the seat belt using a with Soloy Aviation Solutions kit supplementary
‘Leatherman’ tool, and summon emergency type certificate number SR00805SE and
services using a mobile phone. He was later
rescued by paramedics and flown to hospital by LTS 101 conversion kit AS350SD1.
rescue helicopter.
In June 2009, after a hard landing and tailrotor
strike, the helicopter’s engine, tailrotor blades,
Pilot information
control rods and drive system components, along
The pilot held a Commercial Pilot (Helicopter) with several skid-type landing gear components
Licence, a helicopter class endorsement on the were replaced. The main rotor blades were
AS350, and a valid Class 1 Medical Certificate. removed, inspected, repaired and reinstalled.
The pilot commenced helicopter training in 2002,
and had a total helicopter experience of At the time of the accident, the helicopter had a
957 hours, including 32.8 hours in the AS350. He total time in service (TTIS) of 19,679.2 hours.
had worked as a casual pilot for the operator over
the last 6 years and this was his first flight to the The maintenance release was valid until 20 July
HLS at Double Mountain South.
2012 or 19,745.3 hours TTIS, and showed that
the last scheduled maintenance was a 25-hourly
The pilot’s logbook showed that he had inspection on 22 August 2011. There were no
satisfactorily completed a helicopter flight review
recorded defects at that time.
on 25 September 2009. The pilot was checked
again on 29 May 2011, before recommencing The helicopter was refuelled the previous day
flying duties following an occurrence in PNG
from new drum stock and had flown 2.4 hours
earlier that year.
since that time.
The passenger reported that the pilot was well
rested and had performed his duties that day in a
normal manner. On the previous day, the pilot flew
1.8 hours in similar operations in the Shoalwater
Bay training area and was on duty for 8.5 hours.
The passengers and pilot were reported to have
dined together that evening and to have retired to
their respective accomodation by 2130.
Weather conditions
Two days prior to the accident, the pilot had flown
5.9 hours in the helicopter from Cairns to
Yeppoon, Qld, in preparation for the for the
planned airwork in the Shoalwater Bay area.
Recorded data from the Bureau of Meteorology
(BoM) weather station at Samuel Hill, which was
located on the coastal plain 25 km east of Double
Mountain, showed a moderate east to eastsouth-easterly wind of up to 15 kts that day.
Rotation of the helicopter about its longitudinal axis.
Rotation of the helicopter about its vertical or normal axis.
The passenger reported that the weather at the
time was fine. He recalled some turbulence as the
helicopter approached the HLS and that the vanes
on the wind turbines at the site were spinning in
the wind 4 .
The design of the wind turbines did not permit them to
provide an accurate indication of the wind strength or
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An Aerological diagram was derived by the BoM
from data that was obtained by weather balloon at
Rockhampton Airport, Qld at 0900 that morning
showed the wind at 2,500 ft as 15 kts from the
east-north-east and a temperature of 16 °C. The
national aeronautical processing inoformation
system had no record of the pilot accessing
weather or NOTAM information for that day.
surrounding vegetation improved helicopter
access. It was reported that the HLS could be
affected by wind ‘rushing’ up the slope but that
generally, a steady wind assisted helicopter
operations at the site.
Wreckage examination
The wreckage of the helicopter was located on a
steep slope about 50 m west of the HLS, in dense
forest (Figure 3). It was oriented on a magnetic
Double Mountain South HLS
bearing of 250°. During the impact sequence, the
The HLS was situated atop the western peak of helicopter descended through the trees at a very
Double Mountain and under the control of the steep angle, breaking off a number of substantial
Department of Defence. It had an elevation of tree branches before impacting the ground.
2,421 ft and was surrounded by trees on three
sides and a mast and antenna array on the other Figure 3: Aerial view of the wreckage
(Figure 2). A number of trees encroached the
approaches to the HLS and the landing surface
was uneven and covered by long grass. Numerous
tree stumps protruded above ground level.
Figure 2: View of the HLS, looking south-east
The helipad was established to permit access to
radio communication equipment associated with
the military training area. Helicopters were the
only means by which maintenance crews could
access that equipment, as there were no roads or
tracks to the site.
The passenger reported that he and the other
passenger had intended to carry out maintenance
of the HLS. That entailed spraying herbicide and
clearing vegetation from around the helipad as
they had done at a previous helipad. He stated
that, although there were environmental concerns
about unneccessarily clearing vegetation, they
took guidance from the pilots as to the extent of
the clearing necessary to ensure safe approaches
and departures from the HLS. The clearing of
vegetation occurred annually as no permanent
herbicides were used in support of that task.
All of the helicopter’s major rotor and dynamic
components were accounted for at the accident
site with the exception of one tailrotor blade that
was liberated during the impact sequence.
Continuity of the flight control system was
Blade cuts on the tree branches were consistent
with marks on the leading edges of the main rotor
blades and of the remaining tailrotor blade. The
first blade strikes were on branches at a height of
about 23 m on a tree that was about 9 m back
along the swath through the trees.
The helicopter operator described operations into
the helipad as not being the most difficult of those The damaged rotor and drive systems displayed
in the Shoalwater Bay military training area but, as
evidence of being powered at the time the
with most of them, ongoing clearing of the
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helicopter contacted the trees. A number of
components from those systems and of the
helicopter’s flight controls were retained for
technical examination. The pilot’s Global
Positioning System equipment was also
Range officer SAR watch
The range officer for the Shoalwater Bay military
training area maintained a SAR watch over the
helicopter operations in the training area. That
entailed radio communication with helicopter
occupants via portable radio sets.
A substantial quantity of Avtur (aviation turbine Helicopter crews were required to report leaving
each HLS with an estimated time of arrival at the
fuel) was present in the helicopter’s fuel tank.
next HLS, and to report when safely on the
ground. If no report was received after landing
Survival aspects
then the range officer, if unable to establish the
safety of the helicopter crew, would alert
Helicopter and operator equipment
emergency services.
The helicopter was equipped with an ARTEX
ME406 emergency locator transmitter (ELT).
When armed, the ELT was designed to activate on
impact and transmit a distress signal on
frequency 406 MHz. The COSPAS-SARSAT
international satellite-aided tracking system
detected distress signals from activated ELTs and
relayed those signals on a 24-hours a day basis to
the Rescue Coordination Centre (RCC) of the
Australian Maritime Safety Authority (AMSA),
through ground receiver stations.
The ELT was registered with AMSA, which meant
that a distress signal from the beacon would
direct the RCC to the registration database that
held information such as the aircraft’s registration
and relevant emergency contact names and
telephone numbers. Although the helicopter’s ELT
activated, its antenna, which was mounted on top
of the helicopter’s tail boom, had separated on
impact. Consequently, its distress signal was not
received by the RCC.
The operator of the helicopter had also installed a
flight monitoring system that used satellite and
web-based communication systems to allow the
operator to receive accurate information on the
location of company aircraft every 10 minutes
while they were in flight. An alert and the location
of the helicopter was also provided in the event of
an emergency. As such, it supplemented the other
methods of search and rescue (SAR) alerting.
There was no record of a SARTIME 5 being lodged
with CENSAR 6 for the flight.
Further investigation
The investigation is continuing and will include
further examination of the:
• helicopter’s maintenance records
• recovered flight control system components
• helicopter’s performance, weight and balance
• pilot’s flying experience and training
• helicopter landing site and the environmental
conditions at the time
• recorded data from the recovered Global
Positioning System equipment.
In an emergency, the flight monitoring system
stopped transmitting to the website, immediately
generating distress messages that were sent by
text and email to the operator’s nominated
personnel. Those messages contained an affected
aircraft’s last recorded position, speed, altitude
and direction of flight.
The operator reported that on the day, the system
alerted the operations manager to an emergency
and that the operations manager then called the
pilot’s mobile phone. When that call was diverted
to message bank, the manager had contacted
emergency services.
Time nominated by a pilot for the initiation of Search and
Rescue action if a report from the pilot has not been
received by the nominated unit.
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An automated, centralised SARTIME database that was
used by air traffic services to manage SARTIMES.