Piper Navajo PA-31 Service Manual page 652

351
PIPER NAVAJO SERVICE MANUAL
352
WITH NACELLE WING LOCKERS
THOUT NACELLE WING LOCKERS
Figure 10-5. Test Take-off
10-21. SINGLE OR DUAL ATTITUDE AND DIRECTIONAL GYRO INSTALLATION
WITH DE-ICER BOOTS, H-14 AUTOPILOT AND/OR RMI. (Refer to Figure 10-8.)
a. Remove the access plate to the pneumatic system test gauge tap point by removing
the left aft plate at the top of the right engine nacelle.
b. At the pneumatic manifold in the left side of the nacelle remove the cap from the
tap fitting and install pressure gauge. An accurate gauge with a range from 0 to 20 psi with a
hose long enough to allow the face of the gauge to be observed from the cockpit is desired.
The tap fitting is three-sixteenth straight thread flared. (Refer to Figure 10-5.)
c. Operate one engine at 2500 rpm and check if the pressure gauge at the nacelle reads
10 ± .25 psi. Should the reading not be within tolerance. shutdown the engine and remove
the forward access plate at the top of the nacelle. Loosen the adjustment screw jam nut of
the forward regulator of the dual regulators in the right side of the nacelle and turn the
screw clockwise to increase pressure and counterclockwise to decrease pressure. Tighten
adjustment screw jam nut.
d. Repeat the preceding step for the other engine.
e. Operate both engines at 2500 rpm and check that the pressure gauge in the nacelle
reads 10 ± .50 psi.
f. To check the De-Icer Boot pressure, operate one engine at 2500 RPM, turn on the
De-Icer switch at the switch panel and check if the pressure gauge at the nacelle surges to 18
± .50 psi. Shut-down the engine.
g. Repeat the preceding step for the other engine.
Reissued: 10/12/79
INSTRUMENTS
3D14