Removal Of Cowl Flap Transmission; Cleaning, Inspection And Repair Of Cowl Flap Transmission; Installation Of Cowl Flap Transmission; Rigging And Adjustment Of Cowl Flap - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
8-9. ENGINE COWL FLAP.
8-10.REMOVAL OF COWL FLAP TRANSMISSION. (Refer to Figure 8-2.)
a.
Remove the access plate on the top and left side of the engine nacelle just aft of the fire wall.
b.
Disconnect the electrical leads at the transmission motor.
c.
Disconnect the transmission actuating rod (9) from the torque tube arm (15).
d.
Disconnect the transmission (8) from its mounting bracket (7) and remove it from the engine
nacelle.
e.
The torque tube (11 ) may be removed by disconnecting the two cowl flap control rods (12) from
the torque tube and unriveting arm extensions (2), both at the forward side of the fire wall, and removing
the cap bolts (13) that secure the torque tube bearing blocks (14).
8-11. CLEANING, INSPECTION AND REPAIR OF COWL FLAP TRANSMISSION.
a. Clean the transmission assembly with a suitable solvent.
b.
Inspect the transmission tube (5) for excessive end or side play on the transmission screw (6).
c.
Ascertain that the transmission tube (5), screw (6) and rod (9) are not distorted or bent.
d. Check that the screw bearing is not loose on the transmission screw (6) or within the transmission
housing (8). Excess wear can be determined by holding the transmission and moving the screw up and
down.
e.
Check for excess wear within the transmission (8) by turning the screw (6) by hand and noting
the end and side play in the transmission drive shaft. End play should not be great enough to cause end
pressure on the motor drive shaft.
f.
Should any of these checks show excess wear, corrosion or damage, the transmission or its
components should be replaced.
g.
After the transmission screw and tube have been cleaned and dried, a coating of Aircraft Grease
and Actuator Grease, Specification MIL-G-23827 should be applied to the screw on Dukes transmission.
h. When the transmission assembly is disassembled for any reason or at 500 hours, the Dukes
transmission should be repacked 3/4 minimum full with Dukes Formula No. 2 P/N 2196-74-1 grease.
8-12. INSTALLATION OF COWL FLAP TRANSMISSION. (Refer to Figure 8-2.)
a.
Install the torque tube (11) with bearing blocks (14). Tighten the bearing block bolts after the
tube and both blocks are in position.
b.
Position the transmission assembly on its mounting bracket (7) and secure. Allow the
transmission to rotate on its mounting bolt.
c. Attach the transmission actuating rod (9) on the left torque tube arm (15). Tighten connecting
bolt finger tight and safety.
d.
Attach the arm extensions (2) on the torque tube arms and secure with rivets.
e. Connect the electrical leads.
f. Check adjustment of cowl flap per paragraph 8-13 and position sender per 8-16.
g. Install access plates.
8-13. RIGGING AND ADJUSTMENT OF COWL FLAP. (Refer to Figure 8-2.)
a. With the cowl flap actuator set to full open position, adjust the rod assemblies (12) to obtain
4.50 inches opening, measured vertically to the bottom of the cowl, at the rear edge of the cowl flap.
b.
With the cowl flap actuator set to the closed position, adjust the support assemblies (31) to
contact the cowl flap plus .12 of an inch preload. (Approximately .75 to 1.00 inch open measured
vertically to the bottom of the cowl, at the rear edge of the cowl flap.)
c. Secure all jam nuts after adjustments have been completed.
8-14. REMOVAL OF COWL FLAP POSITION SENDER ASSEMBLY. (Refer to Figure 8-2.)
a. Remove the access plate located on top of the engine nacelle aft of the fire wall.
b. Disconnect the electrical leads from the sender unit (16).
c. Loosen the bolt assembly (17) that locks the arm (19) on the sender shaft (18).
d.
Turn off the locknut that secures the sender from its mounting bracket.
Reissues:
9/23/80
2H9 POWER PLANT
Reissued: 9/23/80
POWER PLANT