Century 31 Operating Manual

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Flight Systems, Inc.
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CENTURY 31
AUTOPILOT
PILOT'S OPERATING HANDBOOK
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al
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FACTORY SERVICE CENTERS
Century Flight Systems, Inc. has an established Factory owned
and operated Customer Service Center. The personnel
operating this Center are dedicated to providing Customer
satisfaction with our products.
Besides providing technical consultation, Service Center
personnel also provide competent repairs and spares support
to our dealers as well as direct customer in or out of warranty
repair service. The location of our Factory Service Center is
listed below:
MUNICIPAL AIRPORT, MINERAL WELLS, TEXAS
Product Support
Telephone: (940) 325-2517
If at any time you need service at the Center please call and
arrange for an appointment. This way, we can minimize shop
repair time.
CENTURY SERVICE
DIAL DIRECT TOLL FREE
CUSTOMER ASSISTANCE
1-800-433-5634
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CONTENTS
Foreword ....................... een aar arenero Dee. 1
Features == ene DARAN Re e ano o 3
Century 31 Operating Controls..........................—.—..... 4
Master Disconnect/Trim Interrupt ....................—... 6
Preflight Test Sequence... 6
Lateral Operating Modes ................................—.. 9
Pitch Operating Modes ............................... eo 18
Review of Interlocks and Failure Warnings ................. 15
Yaw Damper System .............................000000 DD 17
Directional Gyro........................... enn es 19
NSD-360A ............. arena e nerarereeeaeeaaa rear 19
NSD-360A Controls... e are eos 22
Century 31 Operating Techniques......................... 25
Localizer (LOC) Approach ......................... e. 26
Glide Slope (GS) Automatic Arm
and Coupler...........................eeeme eee eres 32
Localizer Back Course (LOC BC)... 34
VOR Approach ...................... eee ener. 38
VOR Navigation .....................———...eie eee ee eno 44
MaienaneE e: ern RER 48
Emergency OperatiON eee 49
Product Improvements eee. 50
VA e ere ereceós 51
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LOG OF REVISIONS
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FOREWORD
The Century Flight Systems, Inc. Century 31 Autopilot is an
advanced General Aviation Flight Control System utilizing
“State of the Art” electronic techniques.
In this handbook we have detailed the features, functions and
general operating instructions of the Century 31 System.
May we suggest that you do two things:
. Read this handbook and your Airplane Flight Manual
Supplement. This handbook presents general operating
procedures. Each aircraft installation has an Airplane Flight
Manual Supplement or Autopilot Handbook that contains FAA
approved flight procedures and operating limitations in that
particular model aircraft. The appropriate AFM Supplement is
a document, which must be aboard U.S. Registered Aircraft
with the autopilot installed.
. Spend some VFR time with the equipment to become familiar
with its operation so that you may have the full benefit of its
capabilities.
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FEATURES
The Century 31 Autopilot
This autopilot only version uses a standard artificial horizon in
combination with a directional gyro (DG) or an NSD-360A
Horizontal Situation Indicator (HSI). A Century Flight Systems,
Inc. Yaw Damper (Y/D) may be incorporated with the Century
31 when a Y/D is certified for your plane.
An outstanding feature of the Century 31 is that it has a rate
based inner loop for short-term dynamics. This means that
rate information is derived from the horizon so that motion
about the roll and pitch axis is programmed to occur at a rate
appropriate to the activity. Examples of controlled rate motion
are as follows:
ROLL AXIS:
Heading Command -- Roll at 5° per second diminishing
near bank limit.
Navigation Soft Mode -- Roll at 2.5° per second to
reduced bank limit.
Gust disturbances -- Resisted by certificated servo
velocity.
PITCH AXIS:
Command Attitude -- 0.7° per second attitude change.
Gust Recovery -- Maximum rate consistent with
passenger comfort.
Maximum System Capability -- 2.4° per second.
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CENTURY OPERATING CONTROLS
The Mode Programmer pushbutton switch
placards are lighted and dimming is provided by
the control panel light dimmer switch.
AP. + NAV APR REV
“TEST AT AU GS ©
The Mode Annunciator light intensity is
controlled automatically by a self-contained
ambient light level sensor; this feature provides
optimum Mode Annunciator light level for all
cockpit lighting conditions. The Century 31
Autopilot is activated with the Aircraft Master
switch and operates in a low power state until the
autopilot operation is desired. Mode selection is
made by pushing the desired mode switch on the
Mode Programmer. The selected mode will be
illuminated on the Mode Annunciator.
AP HDG NAV APR REV |)
TEST ATT ALT GS о
HDG NAV APR REV TEST ALT ||
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ee
A separate Trim Master switch is located on the
Control Panel. Autotrim function is activated by
the Autopilot Engage switch.
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Autopilot ON-OFF - Autopilot engage is accomplished by
pressing the momentary ON-OFF rocker switch on the left side
of the Programmer. The Autopilot will engage in the HDG and
ATT modes with synchronization to the existing aircraft pitch
attitude.
In HDG mode the aircraft will
track the heading selected on
the DG or HSI. In NAVY,
APR,or REV modes the
aircraft will intercept and track
any properly programmed
radio-defined course.
Instructions for proper radio
set up in these modes are
included in this manual.
In ATT mode the autopilot will
synchronize to the aircraft
pitch attitude upon
engagement.
In ALT mode the aircraft will
synchronize to the pressure
altitude present at the time of
engagement.
The autopilot may be
disengaged by pressing the
momentary ON-OFF rocker
switch on the programmer; by
pressing the AP OFF switch on
the control wheel trim switch;
by pressing the Master
Disconnect/Trim Interrupt
switch, if present on the control
wheel; or by interrupting power
at the Aircraft Master switch.
Disengagement causes the AP
annunciator to flash for 5 seconds.
MANUAL ELECTRIC TRIM - With the Aircraft and Trim Master
switches on, a manually operated electric trim function is
activated by the control wheel trim switch. This switch serves a
dual function:
1. Disengage the autopilot.
2. Activate manual electric trim.
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OFF
AUTOPILOT
DISCONNECT
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Pressing down on the center rocker bar causes
autopilot disengagement. This action also
activates trim enabling power. Movement of the
bar fore or aft causes the trim to run in a
corresponding down or up direction.
MASTER DISCONNECT/
TRIM INTERRUPT
Many Century 31 autopilots incorporate an
additional switch on the control wheel (usually a
red button). Pressing this button will disconnect
the Century 31, the Yaw Damper (if installed),
and will interrupt the operation of the Trim
System. Release of the button will restore power
to the Trim System. However, the Autopilot will
return to the HDG and ATT mode and will require
re-engagement in order to resume automatic
flight.
AUTOTRIM - The Century 31 Autopilot is
equipped with automatic pitch trim. When the
Trim Master switch is on, Autotrim is activated by
engaging the autopilot.
The Autotrim system is fail safe in design. The
integrity of the trim system is verified by the
preflight test.
PREFLIGHT TEST SEQUENCE
CENTURY 31 PREFLIGHT PROCEDURES
NOTE
During system functional check the
system must be provided adequate
D.C. voltage (12.0 VDC or 24 VDC
min.) and instrument air (4.2 in. Hg.
Min.). It is recommended that the
engine be operated to provide the
necessary power and that the
aircraft be positioned in a level
attitude, during the functional check.
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AUTOPILOT/AUTOTRIM -- To be performed
before the first flight of each day.
1.
2.
10.
Tha
Trim Master switch -- ON.
Engage autopilot.
Move the heading bug left and right of the
lubber line. Observe that the control wheel
moves in the direction of the heading bug
displacement.
Press the DN switch -- verify that the
control wheel moves in the down direction.
Verify that after approximately a 3 second
delay, the trim moves in the down
direction.
Press the UP switch -- verify that the
control wheel moves in the up direction.
Verify that after approximately a 3 second
delay, the trim moves in the up direction.
Grasp control wheel and override roll and
pitch servo actuators to assure override
capability.
Hold control yoke and disengage autopilot
by activating the AP OFF switch on the
control wheel.
Check controls through full travel in roll
and pitch to assure complete autopilot
disengagement.
Press and hold the TEST switch — all mode
annunciator light with AP flashing.
Release the TEST switch after all
annunciator lights except HDG, ATT, and
TEST turn off.
Press the DN switch -- HDG, ATT, and
TEST remain on.
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12.
13.
14,
15.
16.
Press the UP switch — HDG, ATT, and
TEST remain on
Momentarily press the TEST switch —
HDG and ATT remain on, TEST flashes.
Press the DN switch — The TEST light
remains off as long as the DN switch is
held.
Press the UP switch — The TEST light
remains off as long as the UP switch is
held
Momentarily press the TEST switch —
HDG and ATT lights remain on and the
TEST light goes out.
COMMAND TRIM SYSTEM — To be performed
before the first flight of each day.
Using the control wheel trim switch, verify
normal trim up and down operation.
Depress and hold the center bar on the
control wheel trim switch. Observe that the
trim system does not operate.
Release the center bar on the control
wheel trim switch. Move the control wheel
trim switch fore and aft. Observe that the
trim system does not operate.
This completes the test sequences.
CAUTION
Any failure of the above procedures
indicates that a failure exists in the system
and the system shall not be operated until
the failure has been located and corrected.
CAUTION
Check the elevator trim setting before
takeoff.
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LATERAL OPERATING MODES
HEADING — In HDG mode the autopilot will capture and hold the
heading selected on the DG or HSI. HDG annunciator will illuminate.
HDG
4
HDG NAV APR REV TEST ALT
Hei
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NAVIGATION - In NAV mode the autopilot has an automatic 45°
VOR-LOC intercept angle. Selected angle intercepts are available
when the system is equipped with an NSD-360A or other
HSI.
NAV
7 =,
f ON AP NAV
| ALT O |
HDG NAV APR REV TEST ALT
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When executing an intercept, the rate at which the aircraft is closing
upon the selected radio-defined course is determined by the computer
and at the proper time an on-course turn is initiated. Thirty-five
seconds after the on-course turn the computer will reduce its bank
limits to 13°. After 70 seconds the bank limits will be reduced to 8° to
produce a “soft” navigation mode when tracking a VOR signal. The
system will remain in “soft” mode during station passage. However, if
a new course, which requires re-intercept, is selected, the “soft” mode
will unlock and the intercept seguence will reoccur.
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NOTES
The NAV mode should be used
when executing a holding pattern on
the localizer to prevent automatic
glide slope coupling.
When radio receiver is tuned to a
localizer frequency, the coupler will
operate with localizer (APR)
dynamics in the NAV mode.
HEADING SYSTEMS
In systems equipped with a DG the autopilot-
heading bug must be set to match the selected
VOR radial.
In systems equipped with an NSD-360A or other
HSI instrument, the heading bug is disabled when
in the NAV, APR, or REV modes. lIn these
modes the azimuth information to the autopilot is
provided by the radio course pointer.
NOTES
In systems equipped with an NSD-
360A or other HSI always set the
radio course pointer to the Front
Course Inbound Heading when
operating in the APR or REV
modes.
In systems equipped with a DG,
always set the heading bug to the
final approach heading to the
airport.
See section on operating
techniques for additional operating
instructions for the NSD-360A.
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SELECTED INTERCEPT ANGLE
In systems equipped with an NSD-360A or other HSI, a
selected intercept angle function is available while operating in
the NAV, APR, and REV modes.
Selected angle intercepts are initiated by performing the
following steps:
1.
While operating in the HDG mode, set the course
pointer to the desired radial.
Set the heading bug on the NSD to the desired
intercept heading]
Press the HDG and NAV, HDG and APR or HDG
and REV mode buttons simultaneously.
1 ON AP HDG NAV
| =
HDG NAV APR REV TEST
ee | [YY Te
rere
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Both HDG and the selected lateral mode will now illuminate on
the annunciator. As the aircraft begins its on-course turn, the
HDG annunciator will extinguish indicating that the system has
captured the selected radio course and is now receiving
azimuth input from the radio course pointer.
NOTE
If valid radio signal is lost after initiating a selected
angle intercept, the applicable navigation mode
annunciator will flash and the autopilot will remain in
the HDG mode.
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or
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APR
REV
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APPROACH — The APR mode provides an automatic 45°
VOR-LOC intercept angle and selected angle intercepts when
the system is equipped with an NSD-360A or other HSI. The
intercept, crosswind, and tracking sequences are similar to
those described in the NAV mode of operation except that 70
seconds after the on-course turn the bank angles are
reduced to 12°. The APR mode has additional enabling logic
for the automatic glide slope arm, capture, and track sequence
and must be used on ILS approaches.
REVERSE (Back Course) — The REV mode is for use in
tracking the localizer back course Inbound and front course
Outbound or VOR course Outbound.
Automatic 45° intercepts, selected angle intercepts, crosswind
correction and tracking are as described in the APR mode
except that response to radio signals is reversed.
>
AP REV
| = =
HDG NAV APR REV TEST ALT
OFF | LÀ | UP
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|: © © Ф © 3
16
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NOTES
When using an NSD-360A or other HSI always
set the radio course pointer to the inbound front
course localizer heading.
When using a DG, always set the heading bug to
the final approach heading to the airport.
PITCH OPERATING MODES
ALTITUDE - ALT mode will cause the aircraft to maintain the
pressure altitude present at the time of ALT engagement.
ALT may be engaged at maximum rate of climb or descent, but
for passenger comfort, rate of climb or descent should be
reduced to 1,000 feet per minute prior to ALT engagement.
Depressing the pitch data modifier either UP or DN will shift the
AP mode back to ATT mode.
ATTITUDE — ATT mode places pitch command with the pitch
data modifier. Pitch is always synchronized to the existing
aircraft attitude. When engaging the autopilot or when
transferring the system to ATT from ALT, the aircraft will
maintain its existing attitude.
PITCH DATA MODIFIER — The pitch data modifier is a
momentary type rocker switch, located on the right side of the
Mode Programmer, used to modify the airplane’s attitude and
to shift the AP from the ALT mode to the ATT mode.
GLIDE SLOPE COUPLING — In the presence of selected APR
mode only and other enabling logic, the glide slope function is
fully automatic. Therefore, no GS engage switch is used.
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ATT
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GS mode may be entered from either ATT or ALT
mode, from either above or below the glide slope.
Capture of the glide slope depends upon
satisfying conditions, which will complete the
arming sequence. After arming, capture will
occur just before glide slope interception so as to
rotate smoothly to interception. This “anticipative
capture” point is determined by the rate of closure
satisfying a computer equation. In order for the
GS mode to arm, the following conditions must
exist simultaneously:
1. No. 1 NAV radio channeled to a localizer
frequency.
2. Localizer deviation must be less than 90%
either side of center.
3. À valid localizer signal (no flag).
4. A valid glide slope signal (no flag).
5. APR mode selected.
When these conditions are met the GS
annunciator will illuminate in conjunction with the
active pitch mode annunciator indicating glide
slope is armed.
When “anticipative capturing” occurs, the active
pitch mode annunciator will extinguish leaving
only the illuminated GS annunciator to indicate
that transition to the glide slope signal has
occurred.
The GS mode may be deactivated by selection of
any other pitch mode (ALT, ATT) but automatic
recapture of the glide slope may occur in ALT or
ATT modes.
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NOTES
The NAV mode should be used when executing a
holding pattern on the localizer to prevent automatic
glide slope coupling.
When radio receiver is tuned to a localizer frequency,
the coupler will operate with localizer (APR) dynamics
in the NAV mode.
CWS MODE (Pitch Sync) — The system is equipped with a
control wheel steering switch located on the horn of the pilot's
control wheel. When depressed, this switch will disengage the
roll and pitch servos to allow manual maneuvering.
When released, the system will re-engage in the lateral (roll)
mode previously in use.
If the autopilot is in ALT mode the system will synchronize to
the pressure altitude present upon release of the CWS switch.
If the autopilot is in ATT mode the system will synchronize to
the attitude present at the time of release.
REVIEW OF INTERLOCKS AND
FAILURE WARNINGS
The Century 31 System includes a number of automatic
interlocks that will prevent system operation or individual mode
operation if the input information is not valid or if other pre-
requisite conditions do not exist. In addition to the interlocks,
the system will annunciate various failure conditions as
advisory information for the pilot. Following is a brief
description of the interlocks and warnings provided.
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CWS SWITCH
WHEEL SWITCH CONFIGURA.
TIONS VARY WITH AIRCRAFT
MODEL.
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INTERLOCKS
Autopilot engagement is inhibited unless valid
gyro excitation is being provided by the system.
Selection of ALT mode is inhibited if the system
altitude information is unreliable or if the entire
system has not been powered for a time sufficient
to allow temperature stabilization, usually 2 to 6
minutes depending on ambient temperature.
If the navigation information becomes invalid
during selected angle intercepts the appropriate
NAV/APR/REV annunciator will flash and
automatic mode switching from HDG to the
armed navigation mode will be inhibited.
WARNINGS
LOW VOLTAGE — When the aircraft bus voltage
provided the system falls below the minimum
required for reliable system function, any mode
annunciator not already illuminated will flash.
ATTITUDE GYRO EXCITATION — Absence of
valid gyro excitation will cause the autopilot to
disengage and the AP annunciator to flash. The
autopilot cannot be re-engaged until this condition
IS corrected.
AP DISENGAGEMENT — Anytime the autopilot is
disengaged the AP annunciator will flash for
approximately 5.0 seconds, then remain off.
NAVIGATION INFORMATION INVALID — The
appropriate navigation mode annunciator will
flash when selected and invalid navigation signals
are present (NAV flag in view).
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GLIDE SLOPE INFORMATION INVALID
The GS annunciator will flash when glide slope information
is invalid or any other GS Arming condition is lost (GS flag
in view) after glide slope capture. "If valid glide slope
information or any other GS Arming condition is not
available during the arming sequence, the system will not
arm and glide slope capture will not occur.
YAW DAMPER SYSTEM
(OPTIONAL)
The Century Flight Systems, Inc. Yaw Damper System is a
frequently installed option with the Century 31. The system has
only one control-the ON-OFF Push Button. The system is an
independent subsystem that may be used with or without the
Century 31.
For pilot assistance and passenger comfort, its function is
to add additional stability to the yaw axis of the aircraft and
minimize any tendency to hunt or dutch roll in the aircraft.
In addition, the Yaw Damper incorporates an “electronic
ball” to assist in coordinating turns and trimming the aircraft
under conditions of asymmetric power. The Yaw Damper
does not ordinarily compensate for rudder trim variations
with speed changes and therefore may “bump” the rudder
controls slightly when engaged or disengaged at speeds
other than that for which it is adjusted.
The Yaw Damper is engaged by pressing the ON-OFF
Push Button. An “ON” light in the controller confirms the
Y/D is engaged. It is disengaged by pressing the ON-OFF
Push Button or by pressing the Master Disconnect/Trim
Interrupt Button. The “ON” light will extinguish.
21
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Miniature Lubber Line Autopilot
Airplane Heading Bug
Card Set Knob Heading Selector Knob
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DIRECTIONAL GYRO
The Heading Selector DG replaces the standard
directional gyro and provides a fully visible
heading indicator around the normal DG opening.
The DG dial is marked in 5° intervals and
numbered each 30° around its azimuth. A center
index is provided at the top to align selected
headings. Additional indices are located each
45° to facilitate rapid turn selection without mental
arithmetic. Any heading may be selected, either
before or after engagement, and turns up to 180°
may be programmed directly, either right or left. If
the heading indicator is rotated beyond 180° from
the DG card heading, the heading selector will
command a reversal in bank to reach the
resultant selected heading in the shortest
direction.
The DG card is normally set to the magnetic
compass with the card set knob on the left in the
usual fashion, while the heading selector indicator
is rotated by the heading selector knob on the
right. Direction of rotation of both the knob and
indicator commands the same direction of turn.
NSD-360A
AND OTHER COMPASS SYSTEMS
The Century 31 autopilot may be optionally equipped
with the Century Flight Systems, Inc. NSD-360A. The
explanation which follows will be based on the NSD-
360A; however, the principles will apply equally to the
compass systems of other manufacturers provided the
differences in design, features and concepts are
ascertained and allowed for, such as slaving, knob
location, size, etc.
The NSD-360A (Navigation Situation Display) is
an integrated HSI instrument combining an air
driven gyro and an electrically servo heading card
with VOR/Localizer and Glide Slope information.
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Radio Course Pointer
Autopilot N Lubber Line Heading Flag*
Ce Ve
Heading Bug _.
A | Ze а Meter
17 <A
EEN
VIUDO
-
A Nav Flag*
Miniature
y Airplane
=— Compass Card
Left-Right
— Deviation
Bar
Glide Slope Flag*
Course Selector Heading Selector Knob/
Glide Slope Meter Card Set (Push to Set)
Pointer
*Red and White Striped
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NOTES
The NSD has an optional slaving feature that requires
initial heading setting on start-up. Subsequent resetting of
the heading card, required manually on non-slaved
versions, is automatically accomplished with the slaved
version.
Proper heading synchronization must be verified on both
non-slaved and slaved NSD-360A units. This is
accomplished by comparing the heading displayed under
the lubber line with the magnetic compass.
The NSD-360A incorporates a heading warning flag to warn of loss
of either air or electric power. Appearance of the flag during flight
should be sufficient grounds to question the validity of the
displayed heading. In slaved versions, the slaving meter should
oscillate about a 45° point to show that the slaving circuits are
accomplishing their function. Should the needle remain motionless
or either vertical or horizontal for an extended period (two minutes)
in level flight, the heading should be manually set using the
magnetic compass and the performance of the heading card
observed. If this condition persists, set the slaving mode switch to
free gyro. In free gyro mode, the instrument must be periodically
reset to manually counteract the effects of gyro precession.
NOTE
Do not set heading card when turning as the magnetic
compass and magnetic slaving systems are not reliable
references when the aircraft is banked.
29
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SLAVING METER
N
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NSD-360A CONTROLS
The heading selector/card set knob is used to move the
heading bug relative to the heading card. It is also used
to set the heading card to the aircraft heading by
pushing in and rotating the knob. When setting has
been accomplished, the knob is released. The heading
selector/card set knob should not be pushed in when
setting the heading bug.
The course selector knob is used to adjust the radio
course pointer to the desired course. Selection of the
autopilot course automatically sets the internal VOR
resolver to the identical VOR radial. Readout of VOR
left-right information is made by observing the center
segment of the radio course pointer.
DISPLAYS
NSD-360A VOR/Localizer left-right deviation is
displayed by the center segment of the radio course
pointer. Note that the airplane in the center of the
instrument display gives a pictorial representation of the
Navigation Situation. In the illustration, the aircraft is
approaching the desired radial at about 20° intercept.
When operating in the VOR mode, the display always
gives the correct display if the heading card is matched
to the magnetic heading. When operating in the
localizer mode, the radio course pointer should be
placed on the INBOUND front course heading. The
display will then be correct for either front or back
course.
During Back Course Approaches, the display will be
inverted and the tail of the radio course pointer will
indicate the back course heading. The Left-Right needle
sensing will require turns toward the needle for course
centerline.
26
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“TO” FLAG - ‘FROM’ FLAG
The to and from flags point in the direction of the VOR
Station. To or from is pictorially represented.
NAV WARNING FLAG
The NAV warning flag will appear if the signal being
received is not suitable for NAVigation.
In the NSD-360-A, separate “NAV” and “TO-FROM”
meter movements are used. Good navigation data will
be indicated in both VOR and Localizer mode by
absence of the NAV Flag. In the localizer mode the
"TO-FROM” arrows may remain out of view (depending
on NAV converter design).
GLIDE SLOPE
The Glide Slope meter on the left side of the instrument
displays conventional glide slope information — location
of glide slope centerline is pictorially represented.
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NSD-360A
>
e
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“ON GLIDE SLOPE" BELOW GLIDE SLOPE
(FLY UP)
7
ABOVE GLIDE SLOPE
(FLY DOWN)
The Glide Slope Flag is on the left side of the
instrument. It is arranged so that it will obstruct view of
the glide slope meter if a glide slope signal is not
available or is unsuitable for guidance.
27
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IMPORTANT NOTICE
Because the NSD-360A incorporates an
integrated course/left-right display and OBS
resolver, the use of a NAV-1/NAV-2 selector
switch is not recommended with the NSD-360A
for left-right information.
The Century 31 requires left-right data and
course error data that is related to the actual
heading of the aircraft. The use of a NAV-1/NAV-
2 selector switch would involve complex
operational techniques that would add confusion
in moments of stress and its installation is
therefore not recommended.
28
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CENTURY 31
OPERATING TECHNIQUES
In the pages that follow, we have included
techniques for:
Localizer Approaches }
ILS
Glide Slope Arming & Coupling
Localizer Back Course
VOR Approaches
VOR Navigation
The photographs depict the Navigation Situation
at the indicated position as seen on the NSD-
360A. The techniques are equally applicable to
other approved Integrated Compass Systems.
The techniques are also applicable to the 52D254
DG, provided it is understood that the DG
Heading Bug and OBS must be set separately to
achieve the desired results.
CAUTION
When electrical power is first applied to
the NSD-360A instrument the compass
card may rotate or “slew” rapidly. This is
NOT an indication that the compass
system is orienting itself to the proper
magnetic heading. The proper heading
orientation must be verified and set prior
to takeoff and should be verified prior to
approach to landing using the magnetic
compass.
29
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NORTH
Wing
"e,
LOCALIZER (LOC) APPROACH
30
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LOCALIZER (LOC) APPROACH
PSN NSD-360A MODE REMARKS
HDG The localizer or ILS approach begins with transition
from the enroute structure to the outer compass
locater (LOM). The HDG mode and heading bug is
1 used by the pilot to select the desired heading.
ALT Aircraft altitude or rate of descent is controlled using
or ALT, ATT, the Pitch Data Modifier, or Pitch Sync.
ATT The Inbound Front Course direction is selected
with the radio course pointer.
REV Upon reaching the (LOM), press the REV Button.
System will intercept and track OUTBOUND.
ALT NOTE: This is a good time to begin reducing speed
2 for the approach.
or
ATT
REV Altitude appropriate to this phase of the approach
should be controlled using ALT and/or ATT as
L necessary. The procedure turn outbound heading
3 ALT may be preselected using the heading bug.
or
ATT
HDG Press the HDG Button to begin procedure turn.
4 ALT
or
ATT
HDG Proceed outbound in procedure turn until sufficient
5 time has elapsed to assure proper re-interception.
ALT
or
ATT
31
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6851024
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“IND
LOCALIZER (LOC) APPROACH (CONT.)
C31 6851024
LOCALIZER (LOC) APPROACH (Cont.)
PSN NSD-360A MODE REMARKS
FI JA HDG Lead aircraft through procedure turn by moving the
heading bug initially about three-fourth of the way
around the card in the desired direction of the turn.
6
ALT
or
ATT
HDG As the aircraft turns, move the heading bug to the
desired intercept heading. In this case the pilot has
7 selected 205° for a selected angle intercept.
ALT
or
ATT
Y APR If a 45° intercept is desired press APR Button
- system will automatically execute a 45%
8 o A (approximately) intercept.
€ À ALT
PE TEE, or
“pe
xx A ATT
HDG Alternate — If intercept angle other than 45° is
8 desired, set-heading bug to desired intercept
heading. Press both HDG and APR buttons
8A APR simultaneously. System will remain in HDG until
aircraft turns on course, then automatically switch to
APR as indicated by extinguishing the HDG
ALT Annunciator. NOTE: The selected angle intercept
o is particularly useful if being vectored to the final
r
ATT
approach course.
Lid
ad
C31
6851024
NORTH
“La
LOCALIZER (LOC) APPROACH (CONT.)
34
C31 6851024
LOCALIZER (LOC) APPROACH (Cont.)
PSN NSD-360A MODE REMARKS
APR After intercept, system will correct for crosswind,
adjust its internal radio authority, and limit bank
angles. Aircraft altitude should be controlled as
ALT necessary for the approach using ALT and ATT.
9 or Glide slope arming and interception will be
ATT automatic. Missed approach heading may now be
8, programmed..
GS
APR As the glide slope is intercepted, capture is indicated
by extinguishing ALT or ATT with only GS remaining
illuminated.
10
GS
xi 7 If missed approach is required, the following
[TF sequence is typical, see AFM Supplement for details
| хх in specific model aircraft:
OFF |
1. Disconnect A/P
11 2. Add power
3. Initiate G.A. procedure
4. Check for positive rate of climb.
is 5. Retract gear and flaps.
ne 6. Select desired HDG on DG/NSD.
7. Engage AP
8. Adjust climb as desired using Pitch Sync or
« ATT , Pitch Modifier
C31 6851024
GLIDE SLOPE (GS) AUTOMATIC ARM AND COUPLE
36
C31
6851024
Glide Slope (GS) Automatic Arm and Couple
PSN NSD-360A MODE REMARKS
The typical glide slope portion of an ILS begins with
> APR a PON
их Dee the aircraft maintaining altitude for some distance
> YA prior to reaching glide slope interception. However,
1 e A automatic capture will occur if the aircraft is being
| di ws ALT flown in ATT mode downward to the glide slope.
Y ед ol
1 и, АТТ
АРВ The Century 31 recognizes the following conditions:
1. Tuned to Localizer Frequency.
2 2. Localizer less than 90 percent scale.
ALT 3. Valid Localizer signal (no flag).
or 4. Valid Glide Slope signal (no Flag).
ATT 5. APR mode selected.
APR When interception occurs, the Glide Slope Coupler
will couple as indicated by the ALT or ATT
Annunciator extinguishing while the GS Annunciator
3 remains on. Lower the gear and flaps as indicated
in the AFM Supplement.
GS NOTE: Monitor the course guidance and rate of
descent throughout the approach.
HDG Upon reaching DH, disconnect autopilot and land or
manually conduct missed approach.
4
ATT
HDG If missed approach is conducted, as safe altitude is
reached, re-engage autopilot as desired.
5
ATT
37
Note: In order to prevent Automatic Glide Slope
Arm and Coupling (e.g. when holding on the
localizer) use the NAV mode instead of APR.
C31 6851024
у ро
NORTH
am
ta wm
E ree
LOCALIZER BACK COURSE (LOC BC)
38
C31
6851024
Localizer Back Course (LOC BC)
PSN NSD-360A MODE REMARKS
HDG The LOC (BC) back course approach begins with
intercepting the back course OUTBOUND. The
INBOUND Front Course is set on the radio course
pointer, and a 45° intercept to the course is achieved
1 by pressing the NAV button to fly the back course
ALT OUTBOUND.
ATT NOTE: the set up for this example is the same as
flying the front course across the airport and
continuing outbound.
HDG Alternate — If an intercept angle other than 45° is
8 desired, press HDG and NAV simultaneously - the
system will follow heading bug until the intercept turn
NAV begins, then automatically drop HDG, leaving NAV
1A mode active.
ALT
Or
ATT
NAV As outbound tracking begins, select outbound
procedure turn heading with heading bug. Altitude
should be controlled using ALT or ATT as
2 appropriate for this phase of the approach.
ALT
or
ATT
‘у HDG When outbound procedure turn heading is desired,
Я press HDG Button, fly outbound for sufficient time to
= permit re-interception.
3 LA
AUT
a or
ATT
HDG Lead aircraft through procedure turn initially by
turning heading bug approximately three-fourth
distance around the card in the desired direction of
4 turn.
ALT
or
ATT
39
C31
6851024
7290
NORTH
mod dR
om dr a Ta
poa a me Ta
LE Ta ee
LOCALIZER BACK COURSE (LOC BC) (CONT.)
40
C31
6851024
Localizer Back Course (LOC BC) (Cont.)
PSN NSD-360A MODE REMARKS
HDG As aircraft turns, set heading bug to inbound
procedure turn heading.
5
ALT
or
ATT
HDG As aircraft nears inbound procedure turn heading,
press REV button for 45° intercept or use the
6 selected angle intercept.
ALT
or
ATT
REV After intercept, system will correct for crosswind,
adjust its internal radio authority, and limit bank
angles. Heading bug may be aligned with lubber
line or set to missed approach heading. When final
7 ALT approach or step down fix is reached, control rate of
or descent with ATT, Pitch Modifier, and /or Pitch Sync.
ATT
REV Control altitude and rate of descent with ALT, ATT,
8 and/or Pitch Sync.
ATT
HDG For missed approach, disconnect autopilot and
conduct missed approach manually.
9
ATT
41
- 6851024
NORTH
VOR APPROACH
42
C31 6851024
VOR APPROACH
PSN NSD-360A MODE REMARKS
и | > | NAV The VOR approach usually begins from an enroute
situation. If ATC required a descent during this
4 . NE phase, ATT would be used instead of ALT.
"ЭЙ ALT
Y ATT
HDG As the VOR is neared, match the heading bug to
ONE either the course or the lubber line and press HDG
SF = Button. Radio course pointer may now be set for
2 > inbound intermediate course segment.
= id tr ALT
UA: or
- ATT
X : REV As the VOR is crossed, press the REV Button to fly
фо the selected course outbound. Should a lower
a : altitude be desired, Pitch Modifier should be used
3 = and the aircraft flown to the desired altitude.
e or
Be ATT
REV When the desired altitude is reached, press ALT;
the procedure turn outbound heading is preselected
with the heading bug.
4
ALT
or
ATT
HDG Pressing the HDG Button will cause the aircraft to
turn to the selected outbound procedure turn
heading.
5
ALT
or
ATT
43
C31 6851024
NORTH
ны — ны
a" ae
— — В»
a
`
J
=>
© N
\
>
VOR APPROACH (CONT.)
44
C31
6851024
VOR APPROACH (Cont.)
PSN NSD-360A MODE REMARKS
HDG Proceed outbound until sufficient time has elapsed
to assure proper re-interception.
6
ALT
or
ATT
HDG Lead aircraft through procedure turn by moving the
heading bug initially about three-fourth of the way
> around the card in the desired direction of the turn.
ALT
Or
ATT
HDG As the aircraft turns, move the heading bug to the
desired intercept heading.
8
ALT
or
ATT
APR Press APR Button; system wil automatically
execute 45° (approximate) intercept.
9
ALT
or
ATT
HDG Alternate — If intercept angle other than 45° is
8 desired, set-heading bug to desired intercept
heading. Press both HDG and APR simultaneously.
9A APR System will remain in HDG until needle reaches the
> on-course turn point and then automatically switch
ALT to APR as indicated by extinguishing the HDG
or annunciator.
ATT
45
C31 6851024
NORTH
-
=
L
uw |
ws
| De
#
’
== чи
-— ea
VOR APPROACH (CONT.)
46
C31
6851024
VOR APPROACH (Cont.)
PSN NSD-360A MODE REMARKS
| APR After intercept, system will correct for crosswind.
Aircraft altitude should be controlled as appropriate
for the approach by the use of ALT, ATT, or Pitch
10 Sync. Should a course change be required for the
final approach segment, simply move the radio
ATT course pointer to the new course at the VOR.
Missed approach heading may be preprogrammed
with the heading bug.
HDG For missed approach, disconnect autopilot and
conduct manually.
11
ATT
47
6851024
C31
VOR NAVIGATION
48
C31 6851024
VOR NAVIGATION
PSN NSD-360A MODE REMARKS
3% NAV Forty-five degree intercept to a selected radial is
A automatically accomplished by setting the radio
a course pointer to the desired VOR course and
1 = pressing the NAV button on the Programmer.
Sv
É ALT
| 7 HDG Alternate — If an intercept angle of other than 45° is
К “2 8 desired, select the desired course with the radio
EXA MA course pointer and the desired intercept heading
1A 5 fé = NAV with the heading bug. Press HDG and NAV
М со Чао с simultaneously, The system will remain in HDG
JU E o
EY AN mode until aircraft begins on-course turn and then
a De Za MD ALT switch automatically to NAV.
NAV After intercept, system will correct for crosswind,
adjust its internal radio authority and limit bank
angles.
2 e
ALT
NAV If a course change is required at the VOR, simply
reposition the radio course pointer to the NAV
course. If change is small, (less than 45°), system
3 will remain in bank limiting. If change is large, a
ALT standard bank angle will occur during intercept.
NAV Station switching is accomplished by re-channeling
the NAV receiver to the station ahead and
repositioning the radio course pointer to the new
4 course. NOTE: If desired, station change may be
ALT made by setting bug, pressing HDG and then
pressing NAV Button after setting radio course
pointer.
6851024
C31
VOR NAVIGATION (CONT.)
50
C31
6851024
VOR NAVIGATION (Cont.)
PSN NSD-360A MODE REMARKS
то HDG The selected angle intercept feature may be used
for course changes at VORS if desired. When near
& the VOR (5nm, max), match the heading bug to the
5 NAV lubber line and press HDG button. Set new course
with the radio course pointer. Press HDG and NAV
Buttons simultaneously. When the new radial is
ALT intercepted, system will automatically switch to NAV
and acquire the new course.
51
C31
6851024
MAINTENANCE
The Century 31 has been designed and manufactured to render reliable service; however,
some of the system components will require a regular inspection and service. It is
important that agencies selected for service are properly qualified and equipped to render
service on the Century 31.
We have listed several items below to assist you in monitoring your system maintenance.
1.
Gyro Filters — The gyros used with the Century 31 are precision devices whose
performance and service life are in part dependent upon the equality of the air
supply. Poor air quality can significantly reduce gyro life (to hours) and
performance by contaminating bearings. Regular filter maintenance is a good
investment.
2. Aircraft Static Systems — Air leaks and water entrapment can significantly affect
altitude hold performance. Static System maintenance and checks help not only
the AFCS, but assure proper function of static instruments. Altitude Hold units used
by EDO-Avionics should NOT be disconnected during static system checks as they
are designed to withstand such tests without damage.
Periodic inspection and maintenance is recommended for those items of the
autopilot, which attach to the aircraft control systems. During normal inspection is a
good time to make these simple checks on the autopilot.
A. Inspect the bridle cable on the Pitch, Roll, and Yaw Servos for:
1. Condition
2. Tension
3. Freedom - move controls through full range of travel.
B. Inspect bridle cable clamps for:
1. Obstruction.
2. Bolt Torques - 55 +/- 5-inch pounds of torque. Note: This
higher than normal torque is FAA approved and required.
3. Gap between clamp halves - .005” minimum, assures that
cables are under clamping pressure.
C. Inspect Trim Capstans for:
1. Evidence of wear.
2. The clutch should slip instead of cable on capstan if
overpowered.
D. Inspect Trim Cables for:
1. Fraying.
2. Proper tension (high end of spec is usually best).
3. Freedom of travel.
52
C31 6851024
EMERGENCY OPERATION
Appearance of HDG Flag:
1. Check air supply gauge (vac or pressure) for adequate air
supply (4 in. Hg min.).
2. Check NSD-360A circuit breaker.
3. Observe display for proper operation.
To disable heading card - pull circuit breaker and use magnetic
compass for directional data. Note: If heading card is not
operational, autopilot should not be used.
With card disabled - VOR, Localizer and Glide Slope displays are
still functional; use card set to rotate card to aircraft heading for
correct picture.
Slaving Failure - (i.e. failure to self-correct for gyro drift)
Check slave switch (if installed) for SL-1 Position.
Check for HDG Flag.
Check NSD circuit breaker.
Reset heading card while observing slaving meter.
Switch to free gyro and periodically set card as unslaved
gyro.
Eee
C31 6851024
PRODUCT IMPROVEMENTS
Century Flight Systems, Inc. maintains a policy of constant product improvement. Many
times these product improvements are made available on a retrofit basis to owners of
earlier systems. In most cases, retrofit and up-grading is available at moderate cost
through your Century Flight Systems, Inc. Distributor. We must, because of practical
considerations, state that we reserve the right to make changes in product specifications
and prices without incurring obligations.
May we suggest that you ask your installer to enter this significant data in your Operator's
Manual for easy reference:
5 eee e e reee ran reee rarareea ea area errroes
Major component part numbers and serial numbers
Controller/Flight Computer P/N... eran a a
FERRER N EEE EEE TARA EEE EAP EEE FEAR ARE En
RCA RARA PAE ÁLAMO NAAA ACNE AAA E ERA
Registration of your system for warranty purposes will provide us with basic data on your
system, which we will use to make you aware of product improvements.
Should you sell your aircraft, may we ask you to advise the new owner of our continuing
interest and ask him to drop us a note containing the above data so we may up-date our
records.
54
C31
Effective: July 4, 1975
LIMITED WARRANTY CENTURY FLIGHT SYSTEMS
AUTOPILOT
Each new Century Flight Systems Inc. Autopilot is warranted
by the manufacturer to be free from defects in material and
workmanship under normal use, subject to the following
conditions:
1.
Century Flight Systems Inc. will through its designated
service facilities at its option either repair or replace new
components which, shall within (12 months after date of
installation, be found, to Century Flight Systems Inc.
satisfaction, to have been defective in material or
workmanship under normal use.
The warranty registration must be signed and returned
to Century Flight Systems Inc. within ten days of
equipment installation date. In the event that the
registration card is not returned within this time, the date
of shipment from the factory will be deemed to be the
installation date.
This warranty will not apply to any product which has
been installed, repaired or altered in any way
whatsoever in Century Flight Systems Inc. opinion to
adversely affect its performance or reliability, or which
has been subject to misuse, contamination, negligence,
or accident,
Cost of transportation, removal or reinstallation are at
the option of Century Flight Systems Inc..
This is Century Flight Systems Inc. sole express
warranty with respect to the goods supplied herein.
CENTURY FLIGHT SYSTEMS INC. MAKES NO
OTHER EXPRESS WARRANTY OF ANY KIND
WHATSOEVER. CENTURY FLIGHT SYSTEMS INC.
EMPLOYEES MAY HAVE MADE ORAL STATEMENTS
ABOUT THE PRODUCTS DESCRIBED IN THIS
CONTRACT. SUCH STATEMENTS DO NOT
CONSTITUTE WARRANTIES, SHALL NOT BE
RELIED UPON BY THE CUSTOMER, AND ARE NOT
PART OF THE SALE CONTRACT.
THE DURATION OF ANY IMPLIED WARRANTY, AND
OF ALL WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE, SHALL BE
LIMITED TO (12) MONTHS COMMENCING AT DATE
OF INSTALLATION TO THE FULL EXTENT
PERMITTED BY APPLICABLE LAW,
CONSEQUENTIAL DAMAGE OR BREECH OF ANY
WARRANTY ARE HEREBY DISCLAIMED AND
EXCLUDED BY CENTURY FLIGHT SYSTEMS. INC. .
CENTURY FLIGHT SYSTEMS, INC.
P. O. Box 610
Mineral Wells, Texas
76068
January 1982
55
6851024
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