Saab 340B, Руководство по эксплуатации

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AUTOFLIGHT, CAT I
Description
Aircraft Operations Manual
3.1
S
PAGE 2
Jun 01/19
− Combined modes

APPR

GA (FD mode only; selectable on the power
levers).
− Diagnostic mode
(Maintenance — fault isolation in FGAS; selectable
only on ground.)
1.3 FD/AP and Yaw Damper engagement/dis-
engage, autotrim system and Command
Cutout
The FD/AP and Yaw Damper may be engaged in
the normal flight envelope with certain limitation as
stated in AOM 3.2.
The AP can be engaged either to the FD on left
EADI or to the FD on right EADI by pushing the AP
XFR (Auto pilot transfer) button on the APP. An ar-
row beside the AP engaged annunciation on the
EADI’s will show which FD gives steering com-
mands.
The FD display on the EADI can be activated/deac-
tivated by consecutive pushes of the FD button on
the Display Control Panel (DCP) except for in
APPR mode where the FD bar always is displayed.
The AP/YD engage levers on the Autopilot Panel
(APP) allow independent yaw damper engagement.
When engaging the autopilot, however, the yaw
damper will also be engaged as well as the elevator
and rudder autotrim systems. Rudder autotrim is
available also when only YD is engaged. The auto-
trims are continuously retrimming the aircraft de-
pending on the flight conditions in order to minimize
the torque applied on the autopilot servos and to
keep the control forces at zero. Difficulties to trim
out the control forces are indicated on the EADI’s
by the RUD, AIL or EL annunciators.
There is also an AUTO TRIM warning light on the
Central Warning Panel, which will come on if the AP
auto trim or YD auto trim system should fail.
The AP/YD can be disengaged
− by pushing the AP disconnect button on the con-
trol wheel. A second push will reset the aural
warning.
− by moving the AP/YD levers to DISENGAGED
position.
− by selecting GA (L/R Power lever button).
− by operating the pitch trim switches.
(AP disengage only.)
The Stall warning computers will automatically dis-
engage the AP/YD if a stall situation should occur.
The AP/YD will also disengage automatically when
the monitoring function detects certain failures.
When the autopilot becomes disengaged, the aural
warning ”cavalry charge” comes on. The warning
can be reset by pushing the AP disconnect button
and with the GA button.
Command Cutout
The autopilot will not disengage at extreme atti-
tudes. There is however a feature in the autopilot
known as Command Cutout, which means that at
extreme pitch rates/normal accelerations and/or roll
rates/bank angles, the autopilot will cease to give
steering commands. Once the aircraft is back to
normal attitudes ( below the command cutout trig-
gering levels) the autopilot will resume to give steer-
ing commands. The triggering levels for command
cutout are:
− Pitch rate greater than 5

/sec or normal accelera-
tion greater than 0.6 G beyond 1.0 G.
The pitch cutout is canceled when the pitch rate
is less than 5

/sec and normal acceleration less
than 0.2 G beyond 1.0 G.
− Roll rate greater than 21

/sec or bank angle
greater than 45

.
The roll cutout is canceled when the roll rate is
less than 5

/sec and bank angle less than 45

.
Command cutouts will not disengage the autopilot.
1.4 Mode description
VERTICAL MODES
VS, Vertical Speed Mode
− The FCC gives pitch attitude commands to main-
tain the vertical speed existing at time of mode
engagement or
− if already in VS mode at time of
pressing and releasing the VERT SYNC button
on the control wheel. A new vertical speed refer-
ence can be selected by the pitch knob on the
APP in steps of 50 ft.

Basic mode at power on. Selectable by VS
mode button. FCC reverts automatically to VS