AUTOFLIGHT, CAT I
Description
Aircraft Operations Manual
3.1
S
PAGE
1
Jun 01/19
1.
GENERAL
1.1
Flight Guidance & Autopilot System
(FGAS)
The FGAS consists of a Flight Control Computer
(FCC) including the Flight Director/Autopilot (FD/
AP) elevator and rudder autotrim functions and the
Yaw Damper (YD) which provides directional stabil-
ity augmentation. The Yaw Damper and the rudder
autotrim will together provide ”zero ball” function.
The FCC is also provided with a self
−
monitoring
function for maintenance and troubleshooting.
The FCC interfaces with various aircraft systems,
such as the Air Data System (ADS), Attitude and
Heading Reference System (AHRS), NAV radios,
Electronic Flight Instrument System (EFIS), Altitude
Preselect/Alert System (APA). The FCC functions
are controlled by the Mode Select Panel (MSP) Au-
topilot Panel (APP) and by the AP disconnect but-
tons, VERT SYNC buttons and the GA buttons.
The Flight Control Computer (FCC) provides steer-
ing command signals for control of the flight path
during all normal phases of flight. The FCC signals
are fed to the FD command bars/symbols on the
Electronic Attitude Director Indicator (EADI) and to
the control surfaces servo actuators. The FCC
starts operation in Heading (HDG) and Vertical
Speed (VS) modes 10 seconds after AHRS flags
have disappeared. AP/YD can be engaged after
another 30 seconds which is the time of FCC inter-
nal test sequence.
1.2
FD/AP
Flight director, FD
The FD function provides visual guidance com-
mands to fly the aircraft manually or to visually
monitor the AP response to the guidance com-
mands. The guidance commands (pitch and roll
indication) are selected with the FD operating mode
pushbuttons on the MSP. Pitch and roll guidance
cues as well as mode information from the FD are
displayed on the EADI’s. The FD command bars on
the EADI’s direct the pilot to turn, climb or descend.
Autopilot with yaw damper, AP/YD
The AP function controls the aircraft in pitch and roll
maneuvering axes on commands from the FD. The
YD function is a part of the AP rudder steer channel
and provides directional stability. Appropriate con-
trol surfaces are actuated by the AP to control the
aircraft for the selected FD lateral and vertical mode
of operation. The MSP contains pushbuttons for
manual selection of desired FD modes of operation.
The FD modes will if the AP is engaged automati-
cally control aircraft pitch and roll attitude for the
following maneuvers: fly to and maintain a prese-
lected rate of climb or descent; maintain an existing
altitude; descend or climb to and maintain a prese-
lected altitude; fly to and maintain an existing head-
ing; fly to, capture and track a selected VOR or
localizer course; capture and track a glideslope.
FD modes
Captured (active) modes are annunciated on the
EADI’s in green text. Armed (selected) modes are
annunciated on the EADI’s in white text. In the fol-
lowing mode descriptions ”ARM” and ”CAP” are
used to indicate armed or captured phase of the
described mode. When a mode is changed, the
new mode annunciation blinks for 5 secs.
For details on annunciations see Fig. 5 and AOM
15/1.1, NAVIGATION EFIS.
The following modes and functions are available:
−
Vertical modes
VS (basic mode)
IAS
CLIMB
ALT
ALTS
VNAV (if installed)
PTCH (Reversionary Mode; not manually se-
lectable)
VERT SYNC (a synchronization function se-
lectable on the control wheel).
−
Lateral modes
HDG (basic mode)
NAV