GOL 737-8, Руководство по эксплуатации

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737 MAX Flight Crew Operations Manual
Flight Controls -
System Description
MN-FLT-OH-201 9.20.7
Elevator Feel System
The elevator feel computer provides simulated aerodynamic forces using airspeed
(from the elevator pitot system) and stabilizer position. Feel is transmitted to the
control columns by the elevator feel and centering unit. To operate the feel system
the elevator feel computer uses either hydraulic system A or B pressure,
whichever is higher. When either hydraulic system or elevator feel pitot system
fails, excessive differential hydraulic pressure is sensed in the elevator feel
computer and the FEEL DIFF PRESS light illuminates.
Mach Trim System
A Mach trim system provides speed stability at the higher Mach numbers. Mach
trim is automatically accomplished above Mach .615 by adjusting the elevators
with respect to the stabilizer as speed increases. The flight control computers use
Mach information from the ADIRU to compute a Mach trim actuator position.
The Mach trim actuator repositions the elevator feel and centering unit which
adjusts the control column neutral position.
Stabilizer
The horizontal stabilizer is positioned by a single electric trim motor controlled
through either the stab trim switches on the control wheel or autopilot trim. The
stabilizer may also be positioned by manually rotating the stabilizer trim wheel.
Stabilizer Trim
Main electric stabilizer trim switches on each control wheel actuate the electric
trim motor through the main electric stabilizer trim circuit when the airplane is
flown manually. With the autopilot engaged, stabilizer trim is accomplished
through the autopilot stabilizer trim circuit. The main electric and autopilot
stabilizer trim have two speed modes: high speed with flaps extended and low
speed with flaps retracted. In addition, with flaps extended, the autopilot trim
stops stabilizer nose up trim commands when airspeed is three knots or more into
the minimum maneuver speed (amber) bar. If the autopilot is engaged, actuating
either pair of main electric stabilizer trim switches automatically disengages the
autopilot. The stabilizer trim wheels rotate whenever main electric stabilizer trim
is actuated.
The STAB TRIM PRI cutout switch and the STAB TRIM B/U cutout switch are
located on the control stand. If either switch is positioned to CUTOUT, the
autopilot, main electric and Speed Trim System (Speed Trim function and MCAS
function) trim inputs are disconnected from the stabilizer trim motor.
March 1, 2021