Installation Of Lift Detector; Adjustment Of Lift Detector; Cockpit Lighting; Solid State Dimmer Assembly - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
a.
Remove four screws holding the plate around the tab. The lift detector is fastened to this plate; re-
move the unit from wing.
b.
Mark the electrical wires and terminals to facilitate reinstallation. Remove electrical wires from lift
detector; remove lift detector from aircraft.
11-107. INSTALLATION OF LIFT DETECTOR.
a.
Attach electrical wires to their correct terminals on the lift detector.
b.
Position the lift detector with its mounting plate on the wing, determining that the sensor blade
drops down freely; secure in position with the four screws previously removed.
11-108. ADJUSTMENT OF LIFT DETECTOR. The lift detector switch is adjusted at the factory when the
airplane is test flown, and should not require any further adjustment during the normal service life of the
airplane. Should some type of service on the wing require removing the switch, the following instructions will
help in positioning the switch at the proper position.
Loosen the two Phillips head screws; one on either side of the vane. If the stall warning comes on too late,
move the switch up. If the stall warning comes on too early, move the switch down. Retighten the screws after
making any adjustments.
CAUTION
Never try to adjust the switch by bending the vane.
The only way to test the accuracy of the setting is to fly the airplane into a stall condition and NOTE the
speed at which the stall warning comes on. The stall should be made with the flaps and landing gear up and
power off. It may be necessary to make several test flights and alternate adjustments before the desired setting
is obtained. The stall warning should come on not less than five or more than ten miles per hour before the
actual stall occurs.
11-109. COCKPIT LIGHTING. The lighting in the cockpit area of the Navajo Chieftain is controlled by
several types of electrical power connections. The overhead map lights are controlled by on/off switches lo-
cated on the forward part of the overhead panel. In the center of the overhead panel is the potentiometer for
the pilot's flight panel (all instruments, placards and dials necessary for the pilot's flight operation). Another
potentiometer, controlling the light intensity for the overhead gauges and switches, is located on the left for-
ward side of the overhead panel. Two optional dimmers, one for the co-pilot's lights and one for the radio
panel lights, complete the switching arrangement for cockpit lighting. All cockpit lighting, except for radio
lights, is protected by a single circuit breaker. The radio lights are protected by the radio accessories circuit
breaker.
11-110. SOLID STATE DIMMER ASSEMBLY.
11-111. DESCRIPTION OF OPERATION. The potentiometer controlling the pilot's flight panel lighting
is connected to a Solid State Dimmer assembly. This potentiometer controls the electrical flow through the
dimmer to the pilot's panel lights. The voltage is switched on and off simultaneously with the low voltage con-
trol circuit. A switch inside the potentiometer controls this on/off function. When the potentiometer's control
knob is turned on, the lighting intensity is very dim. Lighting intensity increases with a clockwise rotation of
the potentiometer's control knob until it reaches its brightest intensity. At this point the knob will no longer
turn clockwise. Reversal of the knob movement will allow the lighting intensity to be adjusted to a suitable
level. When the lighting intensity is turned to a lower setting, the solid state dimmer serves as a release for
excess heat. Wiring leading to a terminal block and various panel lights completes the circuit for the solid state
dimmer.
Reissued: 9/23/80
ELECTRICAL SYSTEM
3E7