STUDENT GUIDE FOR T-1A AIRCRAFT SYSTEMS
507. FLAP SYSTEM
The electrically controlled and hydraulically operated wing flaps are fowler type flaps. Each
wing has a main flap and an aft flap section. The aft flap is mechanically extended as the main
flap extends. A flap asymmetry detector is provided, that electrically senses differences of more
than 7° between the main flaps. Uncommanded lateral rolling and yawing experienced during
operation of the wing flaps indicates probable asymmetric wing flap condition. If flap
asymmetry occurs, electrical power is interrupted. The flaps will stop in the asymmetrical
position and cannot be moved. An amber annunciator placarded FLAP ASYM will illuminate.
The flap control lever is located on the center pedestal. The flap lever must be seated in a detent
before the flaps will move and also to prevent inadvertent flap movement.
The indicator displays flap position and is located in the top center of the CP's instrument panel.
508. FLAP SYSTEM LIMITS
Refer to Airspeed and Mach Limitations, Section V, T.O. 1T-1A-1, for specific wing flap limits.
509. SPEED BRAKE SYSTEM
The speed brakes are dual rate, electrically controlled, and hydraulically actuated spoiler
surfaces, which can be projected above the upper surface of both aircraft wings. These spoiler
surfaces are used differentially for roll control through control wheel movement. When the
spoiler surfaces are extended together in flight, they provide drag to slow the aircraft. A
hydraulic actuator moves to extend the two surfaces using the same linkage in speed brake
operations as in roll control. Spoiler action for roll control is not affected by speed brake
Speed Brake Switch
The speed brake control switch, located on the pedestal, is a two-position, manually operated,
guarded toggle type switch. The switch positions are placarded EXT and RET for extend and
retract functions, respectively.
Speed Brake Emergency Retract Switch
If the speed brakes will not retract in the normal manner, emergency retraction may be
accomplished by placing the red cover guarded speed brake emergency switch located on the
pedestal to the EMER RET position. This deactivates the extension solenoids and dumps the
hydraulic pressure allowing the speed brakes to be blown down by aerodynamic force.
5-4 HYDRAULIC POWER SUPPLY & SYSTEMS