Landing Gear (Contd.)
If a main landing gear tire is damaged during takeoff, it is possible that braking of
the main gear wheels during retraction may be affected. A spinning tire with a loose tread
must be stopped prior to entering the wheel well or it can cause damage to wheel well
components. When a spinning tire with loose tread impacts a fitting in the wheel well ring
opening, that gear stops retracting and free falls back to the down position. The affected
gear cannot be retracted until the fitting is replaced.
Landing Gear Transfer Unit
Hydraulic system B pressure is available for raising the landing gear through the landing
gear transfer unit. Hydraulic system B supplies the volume of hydraulic fluid required to
raise the landing gear at the normal rate when all of the following conditions exist:
- Airborne.
- No. 1 engine RPM drops below a limit value.
- LANDING GEAR lever is positioned UP.
- Either main landing gear is not up and locked.
Landing Gear Extension
When the LANDING GEAR lever is moved to DN, hydraulic system A pressure is used to
release the uplocks. The landing gear extends by hydraulic pressure, gravity and air loads.
Overcenter mechanical and hydraulic locks hold the gear at full extension. The nose wheel
doors remain open when the gear is down.
