Hydraulic Lines Removal And Installation; Hydraulic System Testing - Piper PA-44-180 SEMINOLE Maintenance Manual

HYDRAULIC LINES.
REMOVAL AND INSTALLATION OF HYDRAULIC LINES.
Remove a damaged hydraulic line by disconnecting the fitting at each end and by disconnecting where
secured by brackets. Refer to Figure 29-9 as an aid in the location of attaching brackets and bends in the lines.
Provide a small container for draining the line. Install a new or repaired line. Operate the pump to purge the
system of air and check fluid level in reservoir.
TESTING HYDRAULIC SYSTEM.
After performing any service or repairs on the hydraulic system, test the system to determine that it
f u n ctions properly.
1. Place airplane on jacks. (Refer to Chapter 7.)
TURN MASTER SWITCH OFF BEFORE INSERTING OR
REMOVING EXTERNAL POWER SUPPLY PLUG.
2. Check master switch is OFF. Connect the airplane to an external power source.
3. With gear down, master switch ON, and circuit breaker closed, place landing gear selector switch in
the UP position. The pump should immediately start operating and the gear retract. The red gear
unsafe light on the instrument panel should light up until the gear is fully retracted. The hydraulic
pump should stop operating after full gear retraction.
4. Place gear selector switch in DOWN position. The gear should extend and lock in position. Gear
down lights on the instrument panel will light up when all three gears are locked in position. Inspect
hydraulic system for leakage of hydraulic fluid.
5. Recycle the landing gear to determine that it functions properly.
6. Position master switch OFF
7. Disconnect external power source.
PRIOR TO REMOVING THE AIRPLANE FROM JACKS,
TURN MASTER SWITCH ON AND DETERMINE THAT
ALL THREE GEAR DOWN AND LOCKED GREEN
LIGHTS ARE ON. TURN MASTER SWITCH OFF.
7. Remove airplane from jacks.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
— CAUTION —
2C22
29-14-02
Page 29-27
Revised: June 20, 1995