Landing Gear Normal Extension

CHAPTER FIVE

STUDENT GUIDE FOR T-1A AIRCRAFT SYSTEMS

Landing Gear Normal Extension

Placing the handle to the DN position electrically positions the gear door selector valve to the

door open position. When both gear doors are closed and locked, hydraulic pressure to the door-

actuating cylinder is shut off. The landing gear extension cycle requires approximately seven

seconds.

Landing Gear Retraction

Placing the handle to the UP position electrically positions the gear door selector valve to the UP

position. When the fuselage main landing gear doors close and lock, hydraulic fluid to the door

actuating cylinders is shut off. All uplock assemblies are mechanically moved to the locked

position. The retraction cycle takes approximately seven seconds.

Emergency Gear Extension

The landing gear can be lowered by gravity using the emergency gear extension system. Pulling

the EMER L/G DOWN handle releases the main gear door uplocks, the main gear uplocks, and

the nose gear uplock (the handle must be pushed down, then pulled out to approximately 10

inches). Once the landing gear doors open and the landing gear free falls to the down-and-

locked position, stow the handle.

In the event of an emergency gear extension the main gear doors must be raised using pneumatic

pressure through actuation of the EMER DOOR CLOSE handle. Pulling this handle out will

direct pneumatic pressure from the nitrogen bottle to the main gear door actuating cylinders,

which close the doors in approximately three seconds and extinguishes the red UNLOCKED

light. The handle is spring-loaded, and will stow when released.

Landing Gear System Controls and Indicators

Landing Gear Handle

The handle placarded LDG GR is a manually operated control which electrically controls the

position of the landing gear. A solenoid operated locking mechanism is provided to prevent

accidental movement of the handle when the aircraft is on the ground. In flight, the solenoid

releases the handle locking mechanism.

Emergency Landing Gear Down Handle

The emergency gear extension T-handle is located beneath the P's instrument panel. It is safety

wired and placarded EMER L/G DOWN.

Emergency Door Close Handle

The EMER DOOR CLOSE handle is located beneath the P's instrument panel. It has a red knob

placarded PULL, and is safety wired.

5-6 HYDRAULIC POWER SUPPLY & SYSTEMS