Saab 340B, Руководство по эксплуатации

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AUTOFLIGHT, CAT II
Description
Aircraft Operations Manual
3.1
O
PAGE 1
Jun 01/19
1. GENERAL
1.1 Flight Guidance & Autopilot System
(FGAS)
The FGAS consists of a Flight Control Computer
(FCC) including two independent Flight Directors
and a single, fail passive Autopilot (FD/AP) elevator
and rudder autotrim functions and the Yaw Damper
(YD) which provides directional stability augmenta-
tion. 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 Panels (MSP)
Autopilot Panel (APP) and by the AP disconnect
buttons, VERT SYNC button and GA buttons.
The Flight Control Computer (FCC) provides steer-
ing command signals for control of the flight path in
a coordinated manner during all normal phases of
flight. The FCC signals are fed to the FD command
bars/symbol on the Electronic Attitude Director Indi-
cators (EADI) and to the control surfaces servo ac-
tuators. 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 internal 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, roll and
speed indication) are selected with the FD operating
mode pushbuttons on the MSP. Pitch and roll guid-
ance 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. A Fast/Slow indication reflects aircraft
speed in relation to speed selection.
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
The modes of the two independent FD channels are
synchronized by a cross
− talk function between the
two separate FD computers, except for in APPR
mode.
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).