Ground Test Procedure; Hour Inspection - Piper Cheyenne IIIA Airplane Maintenance Manual

PIPER AIRCRAFT
PA42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Airfoil - Description and Operation (continued)
7. Ground Test Procedure
After establishing test pressure range, connect an external air pressure source to the 3/4-inch
engine pneumatic line. A check valve in the line prevents air from being forced back through the
opposite engine bleed air ports. Activate system and check operating pressure. The pressure
must be within 1 psig of the recommended operating pressure with each inflation.
If deicers do not reach operating pressure, check solenoid valves. If boots deflate slowly, lines or
ejectors could be plugged. Ensure system inflates in approximately 6 + 0.5 seconds. (See
Outboard Wings, Inboard Wings and Empennage section.)
CHART 2
OPERATING PRESSURES
Recommended Operating Pressure
PSIG
18
Test Pressure
PSIG
MIN.
16
MAX.
20
8. 100-Hour Inspection
At each 100-hour inspection, inspect and operate deicer boots as follows:
(a) Carefully inspect deicers for damage or deterioration. Repair or replace damaged boots.
(b) Replace boots showing considerable wear or deterioration.
(c) Inspect all hose connections comprising the pneumatic deicing system. Replace deteriorated
sections of non-kink hose.
(d) Check operation of boots and operating pressure of system.
(e) If new boots are installed, check tube inflation to ensure air connection stems are properly
connected.
(f) Check on-off control switch for proper operation and wiring.
Inflation Area
Pneumatic Deicer Boots Operation
Figure 2
EFFECTIVITY:
040-999
Jan 10/90 30-10-00