Gulfstream G550, Руководство по эксплуатации

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2A-27-50: Horizontal Stabilizer and Wing Flaps
1. General Description:
The aircraft horizontal stabilizer is mounted at the top of the vertical stabilizer. The
horizontal stabilizer is movable in order to provide a flexible aircraft neutral
stability position in the pitch axis as flaps are extended or retracted. As the flaps
extend they effectively produce a large change in the wing airfoil. The airfoil
change moves the center of lift aft, causing a nose down moment in the pitch axis.
The horizontal stabilizer will automatically compensate for pitch changes as the
flaps extend by moving leading edge down, moderating elevator trim change and
conserving elevator deflection for landing. As flaps are retracted, the stabilizer
moves leading edge up to reduce elevator forces as the wing center of lift transits
forward.
The Fowler-type flaps installed on the trailing edge of each wing provide the
additional lift required to fly at slower airspeeds. By extending aft and down, the
flaps change airflow over the wing, effectively lengthening wing chord and
increasing wing thickness. By emulating a larger wing surface, the flaps decrease
takeoff and landing speeds.
2. Description of Subsystems, Units and Components:
A. Horizontal Stabilizer and Actuator
The horizontal stabilizer is an all-metal structure mounted to the top of the
vertical stabilizer at two points. The aft point consists of a shaft installed
through an opening allowing the stabilizer to pivot. The front attachment is
an electrically powered jackscrew that moves the leading edge of the
stabilizer up and down. The range of movement available for the horizontal
stabilizer is 1.25°up to 4.6°down. The jackscrew is driven by an electric
actuator with two motor windings, and incorporates a locking ratchet
mechanism that prevents movement of the stabilizer if there is no electrical
input to the AC drive motor. The two AC motor windings are independently
powered by the left and right standby AC buses that can be energized by
the Hydraulic Motor Generator (HMG) in the event of electrical failure.
Each AC motor winding has an independent essential DC bus powered
control channel for increased redundancy. (The horizontal stabilizer is fully
operational using a single motor and control channel.) A Rotary Variable
Displacement Transducer (RVDT) is mounted on the actuator to provide
feedback to control signals and to furnish position information for display
on the Flight Controls 2/3 synoptic page and on the Horizontal Situation
Indicator (HSI) portion of the Primary Flight Director (PFD). Stabilizer
position data is communicated to MAU #1 and #2 through ARINC-429 bus
connections from the Flap Control Unit (FCU) where it is shared with the
Monitor and Warning System (MWS).
NOTE:
The Crew Alerting System (CAS) messages generated
by the MWS use the following convention to denote
the redundant power and control sources for the
operation of the horizontal stabilizer:
•
Stabilizer channel A = left standby AC power and
left essential DC control
•
Stabilizer channel B = right standby AC power and
OPERATING MANUAL
PRODUCTION AIRCRAFT SYSTEMS
2A-27-00
Page 47
August 14/03
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