Genesys S-TEC 3100 Manual

ATTITUDE
BASED NEXT-
GENERATION
AUTOPILOT
STRAIGHT
& LEVEL
RECOVERY
2-AXIS
OR 3-AXIS
OPTIONS
ENVELOPE
PROTECTION
& ALERTING
Pilot Guide
S-TEC 3100
Digital Flight Control System
Digital and Analog
Pilot Guide
S-TEC 3100 Digital and Analog_COVER.indd 1 1/25/2018 4:24:08 PM

S-TEC 3100 Digital and Analog
iRev A Nov 2018 S-TEC 3100 Digital and Analog
Pilot Operating Guide
and Reference
Digital Flight Control System
S-TEC 3100 Digital and Analog
Doc No 87325
© 2018 Genesys Aerosystems. All Rights Reserved.
Information contained in this document is subject to change without notice.
No part of this document may be reproduced in any form, or by any means,
without prior written consent of Genesys Aerosystems.
Printed in the United States of America. Genesys Aerosystems and S-TEC
logo are registered trademarks of Genesys Aerosystems. All other brand
names and trademarks are the property of their respective holders.
For service or repairs, contact an authorized Genesys Aerosystems
dealer. For product support, contact Genesys Aerosystems.
One S-TEC Way, Municipal Airport, Mineral Wells TX 76067
Phone: [phone] Fax: [phone]
www.genesys-aerosystems.com

S-TEC 3100 Digital and Analog
Rev A Nov 2018
S-TEC 3100 Digital and Analog
ii
Revision Record
Retain this record in front of guide.
Revision
Number Revision Date Notes/Pages changed, added, or deleted by current revision
1st Ed. February 2018
Rev A November 2018 Page 1-3: Added Half Bank (HB) Mode
denition to 1.6.1 Roll Axis Control.
Page 2-1: Fixed spelling error.
Page 2-4: Corrected steps 27 and 28.
Page 3-10: changed trim timings to 3
and 8 seconds in 3.1.11 Automatic Trim
Annunciations.
Page 3-11: Changed trim timings to
8 seconds in 3.1.12. Manual Trim
Annunciation.
Page 3-22: Added 3.6 Half Bank (HB)
Mode and Figure 3-39: Half Bank (HB)
Mode Switch/Annunciator.
Pages 3-22 to 3-25: Subsequent
subheading numbers and gure numbers
in Section 3 adjusted. Table of Contents
and List of Figures and Tables reect
changes.

S-TEC 3100 Digital and Analog
iiiRev A Nov 2018 S-TEC 3100 Digital and Analog
Table of Contents
Section 1 Overview
1.1. Document Organization.................................................................. 1-1
1.2. Purpose .......................................................................................... 1-1
1.3. General Control Theory .................................................................. 1-1
1.4. Analog Limitations .......................................................................... 1-2
1.5. Optional Yaw Damper..................................................................... 1-2
1.6. Principal Modes of Operation ......................................................... 1-3
1.6.1. Roll Axis Control .......................................................................... 1-3
1.6.2. Pitch Axis Control ........................................................................ 1-3
1.6.3. Yaw Axis Control.......................................................................... 1-4
1.7. Block Diagram ................................................................................ 1-4
1.8. Display Legend............................................................................... 1-5
Section 2 Pre-Flight Procedures
2.1. Power-Up Test ................................................................................ 2-1
2.2. Pre-Flight Checks ........................................................................... 2-1
Section 3 In-Flight Procedures
3.1. Normal Operating Procedures........................................................ 3-1
3.1.1. Roll Attitude (ROLL) Mode........................................................... 3-1
3.1.2. Heading (HDG) Mode.................................................................. 3-1
3.1.3. Navigation (NAV) Mode Tracking a VOR..................................... 3-2
3.1.4. GPS Steering (GPSS) Mode ....................................................... 3-4
3.1.5. Control Wheel Steering (CWS) Mode.......................................... 3-4
3.1.6. Pitch Attitude (PITCH) Mode ....................................................... 3-5
3.1.7. Indicated Airspeed (IAS) Mode.................................................... 3-6
3.1.8. Vertical Speed (VS) Mode ........................................................... 3-6
3.1.9. Altitude Hold (ALT HOLD) Mode.................................................. 3-7
3.1.10. Altitude Pre-Select Function ...................................................... 3-8
3.1.11. Automatic Trim Annunciations.................................................. 3-10
3.1.12. Manual Trim Annunciations ......................................................3-11
3.1.13. Manual Electric Trim.................................................................3-11
3.2. Precision Approach Procedures ....................................................3-11
3.2.1. Straight-In ILS Approach ............................................................3-11
3.2.2. ILS Approach with Procedure Turn............................................ 3-13
3.3. Non-Precision Approach Procedures ........................................... 3-13
3.3.1. Straight-In Back Course Approach ............................................ 3-13
3.3.2. Straight-In LOC Approach ......................................................... 3-14
3.3.3. LOC Approach with Procedure Turn.......................................... 3-15

S-TEC 3100 Digital and Analog
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S-TEC 3100 Digital and Analog
iv
3.3.4. GPS Steering (GPSS) RNAV Approach .................................... 3-18
3.4. Level (LVL) Mode ......................................................................... 3-20
3.4.1. Emergency Level Mode............................................................. 3-20
3.5. Yaw Damper (YD) Mode............................................................... 3-21
3.6. Half Bank (HB) Mode.................................................................... 3-22
3.7. Flight Director (FD) Operation ...................................................... 3-22
3.7.1. AP and FD Modes Engaged...................................................... 3-22
3.7.2. FD Mode Engaged and AP Mode Disengaged.......................... 3-23
3.8. Go-Around (GA) Button................................................................ 3-23
3.9. Menu (MNU) Button...................................................................... 3-24
3.10. Automatic Trim Disable............................................................... 3-25
3.11. Autopilot Disconnect ................................................................... 3-25
3.12. Maintenance Mode ..................................................................... 3-25
Section 4 EFIS Integration Options
4.1. Pre-Flight Checks ........................................................................... 4-1
4.2. Indicated Airspeed (IAS) Mode....................................................... 4-1
4.3. Vertical Speed (VS) Mode .............................................................. 4-1
4.4. Altitude Hold (ALT HOLD) Mode..................................................... 4-2
Section 5 Emergency Procedures
5.1. Automatic Trim Disable................................................................... 5-1
Section 6 Operating Parameters
6.1. Roll Axis Limits ............................................................................... 6-1
6.2. Pitch Axis Limits.............................................................................. 6-1
Section 7 Glossary

S-TEC 3100 Digital and Analog
vRev A Nov 2018 S-TEC 3100 Digital and Analog
List of Figures and Tables
Figure 1-1: S-TEC 3100 Without Optional Yaw Damper ........................ 1-2
Figure 1-2: Block Diagram (With Optional Yaw Damper) ....................... 1-4
Figure 1-3: Display Legend .................................................................... 1-5
Table 3-1: Roll Attitude (ROLL) Mode..................................................... 3-1
Figure 3-1: Roll Attitude (ROLL) Mode ................................................... 3-1
Table 3-2: Heading (HDG) Mode ............................................................ 3-2
Figure 3-2: Heading (HDG) Mode .......................................................... 3-2
Table 3-3: Navigation (NAV) Mode ......................................................... 3-2
Figure 3-3: Navigation (NAV) Mode........................................................ 3-3
Figure 3-4: Heading Mode Engaged, Navigation Mode Armed .............. 3-3
Figure 3-5: NAV GPSS ........................................................................... 3-4
Figure 3-6: APR GPSS ........................................................................... 3-4
Figure 3-7: Control Wheel Steering (CWS) Mode .................................. 3-5
Table 3-4: Pitch Attitude (PITCH) Mode.................................................. 3-5
Figure 3-8: Pitch Attitude (PITCH) Mode ................................................ 3-5
Table 3-5: Indicated Airspeed (IAS) Mode.............................................. 3-6
Figure 3-9: Indicated Airspeed (IAS) Mode ............................................ 3-6
Table 3-6: Vertical Speed (VS) Mode ..................................................... 3-7
Figure 3-10: Vertical Speed (VS) Mode.................................................. 3-7
Table 3-7: Altitude Hold (ALT HOLD) Mode............................................ 3-8
Figure 3-11: Altitude Hold (ALT HOLD) Mode......................................... 3-8
Figure 3-12: Target Altitude in Ft. with ALT HOLD Mode Armed............. 3-9
Figure 3-13: Vertical Speed in Units of FPM .......................................... 3-9
Figure 3-14: ALT HOLD CAP Mode...................................................... 3-10
Figure 3-15: Pitch Trim Annunciations - UP.......................................... 3-10
Figure 3-16: Pitch Trim Annunciations - DOWN ................................... 3-10
Figure 3-17: Manual Electric Trim..........................................................3-11
Table 3-8: Straight-In ILS Approach.......................................................3-11
Figure 3-18: APR LOC and ALT HOLD Modes Engaged, GS Mode Armed.
.............................................................................................................. 3-12
Figure 3-19: APR LOC and GS CAP Modes Engaged......................... 3-12
Figure 3-20: APR LOC and GS Modes Engaged ................................. 3-12
Figure 3-21: Straight-In ILS Approach .................................................. 3-13
Table 3-9: Straight-In Back Course Approach ...................................... 3-13
Figure 3-22: REV Mode........................................................................ 3-14
Figure 3-23: Back Inbound LOC Course Procedure............................. 3-14
Table 3-10: Straight-In LOC Approach.................................................. 3-14
Figure 3-24: APR LOC Mode................................................................ 3-15
Figure 3-25: Straight-In LOC Approach ................................................ 3-15
Table 3-11: LOC Approach with Procedure Turn .................................. 3-16
Figure 3-26: LOC Approach with Procedure Turn ................................ 3-16
Figure 3-27: HDG Mode ....................................................................... 3-17

S-TEC 3100 Digital and Analog
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S-TEC 3100 Digital and Analog
vi
Figure 3-28: APR LOC Mode Armed .................................................... 3-17
Figure 3-29: RNAV Approach Procedure.............................................. 3-18
Figure 3-30: GPSS and Pitch Modes Engaged.................................... 3-18
Figure 3-31: GPSL and ALT HOLD Modes Engaged ........................... 3-19
Figure 3-32: GPSV CAP Mode Engaged ............................................. 3-19
Figure 3-33: GPSV Mode Engaged...................................................... 3-20
Figure 3-34: Level Mode, Roll and Pitch Hold Modes .......................... 3-20
Figure 3-35: LVL Mode; Servos Engaged, No AP ................................ 3-21
Figure 3-36: Without Optional Yaw Damper Installed........................... 3-21
Figure 3-37: YD Mode Engaged........................................................... 3-21
Figure 3-38: YD Mode Disengaged...................................................... 3-22
Figure 3-39: Half Bank (HB) Mode Switch/Annunciator ....................... 3-22
Figure 3-40: AP and FD Modes Engaged............................................. 3-23
Figure 3-41: FD Mode Engaged, AP Mode Disengaged ...................... 3-23
Figure 3-42: Go-Around (GA)............................................................... 3-24
Figure 3-43: Mute Icons........................................................................ 3-24
Figure 3-44: Unmute Icon..................................................................... 3-25

Section 1 Overview
1-1Rev A Nov 2018 S-TEC 3100 Digital and Analog
Section 1 Overview
1.1. Document Organization
Section 1 Overview
Section 2 Pre-Flight Procedures
Section 3 In-Flight Procedures
Section 4 EFIS Integration Options
Section 5 Emergency Procedures
Section 6 Operating Parameters
Section 7 Glossary
1.2. Purpose
This pilot guide provides pre-ight and in-ight operating procedures for the
S-TEC 3100 autopilot (AP) for both digital and analog interfaced systems.
NOTE:
This pilot guide must be carried in the aircraft (A/C) and available to
the pilot at all times. It can only be used in conjunction with the Federal
Aviation Administration (FAA) approved Aircraft Flight Manual (AFM)
or Aircraft Flight Manual Supplement (AFMS). Refer to the applicable
AFM or AFMS for A/C specic information, such as unique ground tests,
limitations, and emergency procedures.
The S-TEC 3100 is designed to assist pilots with cockpit workload
management. The ability of the AP to provide optimum assistance
and performance is directly proportional to the pilot’s knowledge of its
operating procedures. Therefore, it is highly recommended that the pilot
develop a thorough understanding of the AP, its modes, and operating
procedures in visual meteorological conditions (VMC) prior to using it
under instrument ight rules (IFR).
1.3. General Control Theory
The S-TEC 3100 is capable of being a two- or three-axis attitude-based
digital ight control system. It is comprised of a computer/programmer,
which performs input/output processing and control laws, with an integrated
bezel/display for mode selection and display, including trim annunciations.

Section 1 Overview
Rev A Nov 2018
S-TEC 3100 Digital and Analog
1-2
S-TEC servos are coupled to the control system. The roll servo is coupled
to the ailerons; the pitch servo is coupled to the elevator; the trim servo is
coupled to the elevator trim; and the optional yaw servo is coupled to the
rudder.
The AP senses roll attitude, roll rate, heading error, and course deviation to
control the roll servo.
The AP senses pitch attitude, pitch rate, pressure altitude, indicated
airspeed (IAS), vertical speed (VS), vertical acceleration, and glideslope
deviation to control the pitch servo.
With the optional yaw control, the AP senses yaw rate and acceleration to
control the yaw servo.
The AP senses an out of trim condition whenever the trim sensor in the
pitch servo is activated. In response to this, the AP drives the trim servo in
the proper direction until the A/C is in trim.
The AP also includes an altitude pre-select function, if enabled.
1.4. Analog Limitations
The S-TEC 3100 relies on digital air data information for advanced functions
such as altitude pre-select. For analog congurations altitude hold is
available, but the ALT target is not selectable.
1.5. Optional Yaw Damper
Some aircraft congurations will not have a yaw damper system installed.
In these cases, the yaw damper button is blank and the YD LED does not
illuminate under any circumstances.
Figure 1-1: S-TEC 3100 Without Optional Yaw Damper

Section 1 Overview
1-3Rev A Nov 2018 S-TEC 3100 Digital and Analog
1.6. Principal Modes of Operation
1.6.1. Roll Axis Control
Autopilot (AP) Mode:Engages roll servo
Flight Director (FD) Mode:Laterally drives steering command bars
Roll Attitude (ROLL) Mode:Holds roll attitude
Heading (HDG) Mode:Turns onto a selected heading and holds it
Navigation (NAV) Mode:Intercepts and tracks a VOR course
Approach (APR) Mode:Intercepts and tracks a LOC front course or GPS
approach inbound
Reverse (REV) Mode: Intercepts and tracks a LOC back course (BC)
inbound or tracks a LOC front course outbound
Control Wheel Steering (CWS) Mode:Captures and holds new roll
attitude, pitch attitude, indicated airspeed, vertical speed, or altitude
GPS Steering (GPSS) Mode:Laterally steers along a ight plan course
dened by GPS/FMS
GPS Lateral Navigation (GPSL) Mode: Laterally steers along an approach
course dened by GPS/FMS approach
Level (LVL) Mode:Returns A/C to wings level attitude from any condition
Half Bank (HB) Mode:Reduces commands in HDG and GPS/FMS steering
by half
Go-Around (GA) Mode:Disengages AP and/or engages FD in ROLL
wings-level mode
1.6.2. Pitch Axis Control
Autopilot (AP) Mode:Engages pitch servo
Flight Director (FD) Mode:Vertically drives steering command bars
Pitch Attitude (PITCH) Mode:Holds pitch attitude
Indicated Airspeed (IAS) Mode:Holds indicated airspeed
Vertical Speed (VS) Mode:Holds vertical speed
Altitude Hold (ALT HOLD) Mode:Holds altitude

Section 1 Overview
Rev A Nov 2018
S-TEC 3100 Digital and Analog
1-4
Glideslope (GS) Mode:Intercepts and tracks glideslope
GPS Vertical Navigation (GPSV) Mode: Vertically steers along a glidepath
dened by a GPS/FMS approach
Level (LVL) Mode:Returns A/C to level ight with a vertical speed of “0”
from any condition
Go-Around Mode (GA) Mode:Disengages AP and/or engages FD in pitch
hold mode with a preset nose-up command
Automatic Trim Mode:Automatically drives pitch trim servo.
1.6.3. Yaw Axis Control
Yaw Damper (YD) Mode: Dampens excessive adverse yaw and coordinates
turns (if installed)
1.7. Block Diagram
Figure 1-2: Block Diagram (With Optional Yaw Damper)

Section 1 Overview
1-5Rev A Nov 2018 S-TEC 3100 Digital and Analog
1.8. Display Legend
Figure 1-3: Display Legend
1) Autopilot (AP) Mode button
2) Flight Director (FD) Mode button
3) Yaw Damper (YD) Mode button (Optional) - (See Figure 1-1)
4) Heading (HDG) Mode button
5) Navigation (NAV) Mode button
6) Approach (APR) Mode button
7) Level (LVL) Mode button
8) Ambient light sensor
9) Indicated Airspeed (IAS) Mode button
10) Vertical Speed (VS) Mode button
11) Altitude Hold (ALT HOLD) Mode button
12) Menu (MNU) Mode button
13) Altitude Selector (SELECT) knobs
14) Up/Down (UP/DN) Modier switch
15) Altitude Selector/Alerter annunciation
16) Active Pitch Mode annunciation
17) Armed Pitch Mode annunciation
18) Active Roll Mode annunciation
19) Armed Roll Mode annunciation
20) Light Emitting Diodes (LEDs)

Section 2 Pre-Flight Procedures
2-1Rev A Nov 2018 S-TEC 3100 Digital and Analog
Section 2 Pre-Flight Procedures
2.1. Power-Up Test
Perform the following actions during power-up.
1) Set battery master switch to ON position.
2) Set avionics master switch to ON position.
3) Set AP master switch to ON position.
4) Set trim master to ON position.
NOTE:
For proper manual electric trim function, both the AP master switch and
trim master switch must be on during the autopilot self-test.
The following occur in sequence:
Self Test In Progress appears during
AP self-test.
ADAHRS INITIALIZING appears during
initial alignment.
AP READY indicates AP is ready for
operation.
NOTE:
No annunciation in the AP/YD status nor ROLL and PITCH blocks
indicates AP READY.
If initial alignment is not valid after
congured start-up time or data
becomes invalid following the alignment,
AP FAIL appears.
2.2. Pre-Flight Checks
Perform the following actions prior to takeoff with engine running. See
Section 4 for EFIS integration options.
1) Move A/C control left and right to sense freedom of movement about
roll axis.

Section 2 Pre-Flight Procedures
Rev A Nov 2018
S-TEC 3100 Digital and Analog
2-2
2) Move A/C control forward and aft to sense freedom of movement
about pitch axis.
3) If yaw damper option is installed, actuate A/C rudder pedals alternately
in succession to sense freedom of movement about yaw axis.
4) Press to engage ROLL,
PITCH, FD, and YD modes. AP,
FD, and YD LEDs, while ROLL and
PITCH appear on AP.
NOTE:
If the yaw damper option is not installed, the YD LED does not
illuminate in step 4.
5) Move A/C control left and right. Reduced freedom of movement
indicates roll servo is engaged. Verify roll servo can be overridden.
6) Move A/C control forward and aft. Reduced freedom of movement
indicates pitch servo is engaged. Verify pitch servo can be overridden.
7) If yaw damper option is installed, actuate A/C rudder pedals alternately
in succession. Reduced freedom of movement indicates yaw servo is
engaged. Verify yaw servo can be overridden.
CAUTION:
If any servo in any axis cannot be overridden or fails to disengage
during the pre-ight checks, the aircraft should not be own and
the autopilot should be inspected by an authorized service facility.
8) Set heading bug under lubber line.
9) Press to engage HDG mode.
HDG replaces ROLL on AP.
10) Turn heading bug to left of lubber line. A/C control turns to the left.
11) Turn heading bug to right of lubber line. A/C control turns to the right.
12) Set heading bug under lubber line. A/C control stops.

Section 2 Pre-Flight Procedures
2-3Rev A Nov 2018 S-TEC 3100 Digital and Analog
13) Press to engage IAS mode.
IAS replaces PITCH on AP. Number
indicates lowest airspeed congured
for A/C in kts.
14) Press/Hold . Airspeed indication increases on AP. (For EFIS
integration, see § 4.1.)
15) Press/Hold . Airspeed indication decreases on AP display. (For
EFIS integration, see § 4.1.)
16) Press to engage VS mode.
VS replaces IAS on AP. Number
indicates current VS in feet per
minute (fpm).
17) Press/Hold until a commanded VS of 500 (500 fpm climbing)
is reached. A/C control moves aft – pilot may have to assist a heavy
yoke. (For EFIS integration, see § 4.1.)
18) Press/Hold until a commanded VS of â500 (500 fpm descending)
is reached. A/C control moves forward. (For EFIS integration, see §
4.1.)
19) Press to engage ALT mode.
ALT HOLD replaces VS on AP, and
VS indication is extinguished.
20) Press/Hold CWS switch to engage
CWS mode. CWS ashes on AP,
while periodic audible alert tone
sounds.
21) Move A/C control left and right. Increased freedom of movement
indicates roll servo is disengaged.
22) Move A/C control forward and aft. Increased freedom of movement
indicates pitch servo is disengaged.
23) Release CWS switch to disengage CWS mode and resume AP control.
CWS is extinguished on AP.
24) Move A/C control left and right. Reduced freedom of movement
indicates roll servo is engaged.

Section 2 Pre-Flight Procedures
Rev A Nov 2018
S-TEC 3100 Digital and Analog
2-4
25) Move A/C control forward and aft. Reduced freedom of movement
indicates pitch servo is engaged.
26) Verify trim master switch is set to ON position.
NOTE:
Reference the AFMS for the particular model as some functionality of
automatic trim may differ.
27) Move A/C controls aft to apply force
to the pitch servo and simulate out-
of-trim condition.
After 3 seconds, pitch trim
annunciation (TRIM â) appears on
AP. Trim wheel runs to counter.
After 8 seconds, TRIM â ashes
and audible alert, “Trim in Motion,”
sounds repeatedly.
28) Move A/C controls forward to apply
force to the pitch servo and simulate
out-of-trim condition.
After 3 seconds, pitch trim
annunciation (TRIM ) appears on
AP. Trim wheel runs to counter.
After 8 seconds, TRIM  ashes
and audible alert, “Trim in Motion,”
sounds repeatedly.
29) Set trim master switch to OFF position.
30) Repeat steps 27 and 28. The results are identical with the exception
that trim does not drive the corresponding axis, and “Check Pitch
Trim” sounds repeatedly to alert the pilot that trim power is off or in a
failed condition.
31) Press and hold AP DISC/TRIM INTR
switch. AP READY appears on AP
and audible alert sounds, while all
other annunciations and all LEDs are
extinguished. “Autopilot Disconnect”
sounds once.

Section 2 Pre-Flight Procedures
2-5Rev A Nov 2018 S-TEC 3100 Digital and Analog
32) Move A/C control left and right. Increased freedom of movement
indicates roll servo is disengaged.
33) Move A/C control forward and aft. Increased freedom of movement
indicates pitch servo is disengaged.
34) If yaw damper option is installed, actuate A/C rudder pedals alternately
in succession. Increased freedom of movement indicates yaw servo
is disengaged.
35) Set trim master switch to ON position.
36) Press both forward and aft on each segment of manual electric trim
switch, independently of the other. In each case, A/C elevator trim
wheel does not run.
37) Press/Hold aft on both segments of manual electric trim switch. TRIM
ashes on AP, and A/C elevator trim wheel runs nose up.
38) Press/Hold AP DISC/TRIM INTR switch. A/C elevator trim wheel stops.
39) Release AP DISC/TRIM INTR switch. A/C elevator trim wheel resumes
running nose up.
40) Release manual electric trim switch. TRIM is extinguished on AP, and
A/C elevator trim wheel stops.
41) Press/Hold forward on both segments of manual electric trim switch.
TRIM ashes on AP, and A/C elevator trim wheel runs nose down.
42) Press/Hold AP DISC/TRIM INTR switch. A/C elevator trim wheel stops.
43) Release AP DISC/TRIM INTR switch. A/C elevator trim wheel resumes
running nose down.
44) Release manual electric trim switch. TRIM is extinguished on AP
display, and A/C elevator trim wheel stops.
45) Press GA switch. FD LED illuminates (AP not engaged), while ROLL
and PITCH appear on AP display.
46) Trim A/C for takeoff.

Section 3 In-Flight Procedures
3-1Rev A Nov 2018 S-TEC 3100 Digital and Analog
Section 3 In-Flight Procedures
3.1. Normal Operating Procedures
3.1.1. Roll Attitude (ROLL) Mode
From any active condition shown in Table 3-1, the corresponding action
engages roll attitude mode. ROLL appears. The AP holds the A/C at its
current (captured) roll attitude.
Table 3-1: Roll Attitude (ROLL) Mode
Active Condition Action Result
AP READY pressed
Roll mode
engaged
pressed
HDG mode engaged pressed
NAV mode engaged pressed
APR mode engaged pressed
Any mode engaged pressed
Figure 3-1: Roll Attitude (ROLL) Mode
3.1.2. Heading (HDG) Mode
Set the heading bug to desired heading on the compass card. From any
active condition shown in Table 3-2, the corresponding action engages
heading mode. HDG appears. The AP turns the A/C onto the selected
heading and holds it. A new heading can be selected thereafter by setting
the heading bug to it.

Section 3 In-Flight Procedures
Rev A Nov 2018
S-TEC 3100 Digital and Analog
3-2
Table 3-2: Heading (HDG) Mode
Active Condition Action Result
Roll mode engaged
pressed HDG mode
engaged
NAV mode engaged
APR mode engaged
REV mode engaged
Figure 3-2: Heading (HDG) Mode
3.1.3. Navigation (NAV) Mode Tracking a VOR
Select the VOR frequency on the navigation receiver. Set course pointer to
desired radial and direction to/from the station on the compass card. From
any active condition shown in Table 3-3, the corresponding action engages
navigation mode. NAV appears.
Table 3-3: Navigation (NAV) Mode
Active Condition Action Result
Roll mode engaged
pressed
NAV mode
engaged
APR mode engaged
REV mode engaged
HDG mode engaged,
NAV mode armed Course captured
NAV GPSS engaged VOR or LOC selected
The AP establishes the A/C on a 45° intercept angle relative to the selected
course, with the exception of a pilot selectable intercept angle (§ 3.1.3.1).
The course is captured upon reaching the point where the AP must begin to
turn the A/C onto the course. After completing the turn, the AP establishes
the crosswind correction angle and tracks the course.

Section 3 In-Flight Procedures
3-3Rev A Nov 2018 S-TEC 3100 Digital and Analog
Figure 3-3: Navigation (NAV) Mode
If a reference signal required for NAV fails, NAV mode transitions to FAIL,
and NAV and FAIL alternately ash until the signal is valid once more. If this
occurs prior to course capture, the AP holds the aircraft’s wings level and
does not attempt to capture the course. However, if this occurs after course
capture, it holds the last known crosswind corrected course and ignores
CDI needle deection.
Once tracking, if CDI needle deection exceeds 50% from center for a
period of 15 seconds, NAV ashes. If the A/C subsequently returns to within
50% CDI needle deection from center, NAV stops ashing but remains.
At point of station passage, the AP recognizes the condition and holds the
last known course. Either allow the A/C to pass over the station and pick it
up again on the other side or select another VOR to track.
While either NAV or APR mode may be used to track a VOR, NAV mode is
recommended. Do not press until cleared for approach and ready to
arm to some vertical guidance.
3.1.3.1. Pilot Selectable Intercept Angle
To select an intercept angle other than 45°, set the heading bug to desired
intercept heading on the compass card, so the difference between this
heading and the desired course is the intercept angle. Set course pointer
to desired course. Engage HDG mode, and press to arm NAV mode.
HDG and NAV appear.
Figure 3-4: Heading Mode Engaged, Navigation Mode Armed