a mechanically operated shutoff valve located between the Combined and
Flight hydraulic system pressure sources and the aileron actuators (as well
as the elevator, rudder and flight / ground spoiler actuator) pressure lines.
The valve consists of two mechanically connected but hydraulically
isolated sections. A controlex cable connects the valve to a FLIGHT
POWER SHUT OFF handle located on the left aft side of the cockpit center
pedestal. See Figure 8.
Moving the FLIGHT POWER SHUT OFF handle up from its stowed
(horizontal) position to the vertical position mechanically closes the flight
power shutoff valve. With the valve closed, operating pressure is removed
from the actuator, allowing the piston to idle.
The resultant advantage of the flight power shutoff provision is the ability to
bypass a malfunctioning actuator (such as would be the need in the
unlikely event of an actuator jam) and manually fly the aircraft. Although
control wheel effort and response time to inputs are increased while in
manual reversion, the aircraft remains capable of positive and harmonious
control.
E. Flight Spoiler System:
(See Figure 15.)
A mixing linkage between the aileron and flight spoiler control mechanisms
mixes control wheel inputs to provide aileron / flight spoiler coordination.
This allows the two outboard spoiler panels on the same side as an upward
moving aileron to extend up to a maximum of 26 ±2° for roll control. If the
speed brakes are extended, the flight spoilers extend up to a maximum of
55 +4/-3°.
As the aileron control mechanism commands an aileron to deflect upward,
the mixing linkage transmits an extend command to the flight spoiler
actuator control valve through push-pull rods, bellcranks and cables. The
control valve then shifts to direct pressure to the flight spoiler actuator. The
normally-extended actuator retracts and the flight spoiler panels follow
aileron movement to assist roll control. The flight spoiler panels on the
opposite wing remain retracted.
F. Roll Trim System:
(See Figure 14 and Figure 15.)
Trim control about the longitudinal axis is controlled by displacing a trim tab
attached to the trailing edge of the left aileron. This is accomplished
through the use of an aileron trim control wheel mounted on the upper aft
end of the center pedestal.
Rotation of the aileron trim control wheel left or right rotates a cable drum
through the use of a torque tube. As the drum rotates, cables transmit the
movement to the aileron trim actuator. Mechanical linkage attached to the
actuator causes the trailing edge of the aileron trim tab to be raised or
lowered.
Movement of the aileron trim control wheel also drives an incorporated
pointer that indicates the units of Left Wing Down (LWD) or Right Wing
Down (RWD) trim from neutral. Total trim wheel travel is approximately 4½
turns from stop to stop. This yields a maximum of 8 units (13 ±1°) of trim
tab deflection from either side of the neutral position.
OPERATING MANUAL
PRODUCTION AIRCRAFT SYSTEMS2A-27-00
Page 44
January 31/02
Revision 6
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