Gulfstream G550, Руководство по эксплуатации

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2A-27-30: Rudder Yaw Control
1. General Description:
The flight crew controls the direction of the aircraft around the vertical axis by
movement of the rudder. The rudder panel is composed of graphite-epoxy fabric
baked at high temperatures to form a strong but light weight structure. The rudder
is positioned by inputs from the pilot or copilot rudder pedals, or by autopilot
electro-servos. The pilot and copilot rudder pedals are connected by a common
torque tube so that either may control rudder movement. (The individual pedal
pairs are adjustable to accommodate differences in pilot leg length.) The common
torque tube is connected by a bellcrank to a single stranded wire cable loop
located on the right side of the aircraft beneath the cockpit and cabin floor. (Since
there is only one rudder flight control surface, there is no need for dual cable
linkages from both yokes to the rudder, nor is there a need for a system to
separate pilot and copilot rudder pedal inputs to the rudder.) The cable loop
incorporates pulleys and bellcranks to route the cable around other installations
beneath the aircraft floor. At the end of the loop is a bellcrank connected to a dual
piston hydraulic actuator. The bellcrank translates movement of the control cable
into lateral displacement inputs to the actuator. The rudder control cable linkage is
illustrated in Figure 7 and the termination of the cable linkage at the rudder
actuator is shown in Figure 8. The actuator has a single shaft with a piston
chamber for each (left and right) hydraulic system. Both hydraulic systems
provide up to three thousand (3,000) psi pressure to assist in moving the rudder
surface. Internal regulator valves limit the pressure output of the two pistons within
the hydraulic actuator to a maximum of fifteen hundred (1,500) psi each to prevent
structural damage to the rudder and vertical stabilizer. The output end of the
hydraulic actuator shaft is connected to linkages that move the rudder around the
pivot point connections on the vertical stabilizer. If one hydraulic system fails, the
regulator valve of the remaining system shifts to provide up to three thousand
(3,000) psi to move the rudder. Additionally, in the event of dual hydraulic system
failures, the auxiliary (AUX) hydraulic pump will power the rudder using the left
system piston in the actuator provided sufficient fluid remains in the auxiliary
reservoir of the left hydraulic system. AUX hydraulic system power for the rudder
is activated by the selection of the STBY RUD (Standby Rudder) switch on the
lower portion of the pilot instrument panel to the left of the standby flight
instruments.
Mechanical stops are incorporated into the rudder mounting structure to physically
limit rudder displacement to a maximum of twenty-two degrees (22°) either side of
neutral, although full displacement is available only at low airspeeds. As airspeed
increases, the airload on the rudder surface increases proportionally. When the
airload on the rudder surface equals the available hydraulic pressure output of the
rudder actuator, no further rudder displacement is possible. The Monitor and
Warning System (MWS) software monitors aircraft speed, angle of attack and
rudder displacement to formulate an advisory message informing the flight crew
when maximum rudder displacement has been reached.
2. Description of Subsystems, Units and Components:
A. Yaw Damper and Autopilot Rudder Operation:
Automatic rudder compensation for aircraft yaw produced by dutch roll
inherent to swept-wing aircraft is provided by the yaw damper function of
the autopilot. The yaw damper function is engaged with the YAW DAMP
ENG / DISENG switch located on the lower pilot side instrument panel
OPERATING MANUAL
PRODUCTION AIRCRAFT SYSTEMS
2A-27-00
Page 23
August 14/03
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