Landing Gear And Brake System Description - Piper Navajo Chieftain PA-31-350 Service Manual

SECTION VII
LANDING GEAR AND BRAKE SYSTEM
7-1. INTRODUCTION. This section provides instructions for remedying difficulties which may arise in the
operation of the landing gear and brake systems. The instructions are organized so that the mechanic can
refer to Descriptions and Principles of Operation for a basic understanding of the systems; Troubleshooting
for a methodical approach in locating the difficulty; Corrective Maintenance for the removal, repair and
installation of components; and Adjustment and Test for the operation of the repaired systems.
7-2. DESCRIPTION AND PRINCIPLE OF OPERATION. The tricycle landing gear system incorporates
air-oil oleo type struts that are hydraulically operated and fully retractable with the nose gear retracting aft
into the nose section and the main gear retracting inboard into the wing. Doors completely cover the gear
when retracted. The nose and outboard main gear doors operate by mechanical linkage and remain open
when the gear is extended. The main gear inboard doors operate hydraulically and are controlled by the
limit switches opening during gear extension and closing again when the gear has fully extended. To prevent
t'e gear from retracting while the airplane is on the ground, an anti-retraction safety switch is located on
the left gear upper torque link, which will not allow the gear actuator lever to move to the gear up position
until weight is off the landing gear allowing the strut to extend to within one-quarter of an inch of full
e xtension.
The nose gear is steerable through a 40 degree arc by the use of the rudder pedals. As the gear retracts,
the steering linkage becomes separated from the gear and is centered, so that the rudder pedal action with the
gear retracted is not impeded by the nose gear operation. For further information refer to Piper Service
Spares Letter No. 352 and Piper Kit - 763 982 nose gear strut assembly modification.
Located on the instrument panel, to the right of the gear selector control, are one red and three green
indicator lights. The red light will show an indication when the gear is not locked in either the up or down
position and the green lights will show when each individual gear is down and locked. There is no indication
light when the gear is up and locked. The red light will also show an indication whenever the inboard gear
doors are not completely closed. A warning horn in the cockpit will sound whenever power from one or
both engines is reduced below 10 to 12 inches of manifold pressure when the gear are not in the down
locked position. This horn will also sound whenever the landing gear selector handle is in the gear up
position while the airplane is on the ground and the master switch is on. If the gear selector handle can be
moved to the up position with the airplane on the ground, it is an indication of an improperly adjusted
selector mechanism or the anti-retraction system is inoperative.
Located in the cockpit between the pilot seats, under the floor access panel, is a hand pump to be used
should the primary hydraulic system fail.
The brakes are hydraulically actuated by individual master cylinders mounted on the left (optional on
right) set of rudder pedals. A reservoir, accessible through the access door on the upper right portion of the
nose section, supplies fluid to each master cylinder. From these cylinders, hydraulic fluid is routed through
lines and hoses to a parking brake valve located on the left aft side of the forward cabin bulkhead, through
the cabin and wings, to the brake assemblies on each main landing gear. To operate the brakes, apply toe
pressure against the top of the rudder pedal. The parking brake may be actuated by applying toe pressure
and at the same time pulling out on the brake handle. To relieve parking brake pressure, apply toe pressure
on the pedals and at the same time push in on the parking brake handle.
Servicing of the hydraulic and brake system is found in Section II.
Revised: 3/11/81 LANDING GEAR AND BRAKE SYSTEM
2D16
NAVAJO CHIEFAIN SERVICE MANUAL