TM 55-1520-240-23-7
9-60
LIGHTING SYSTEMS
(Continued)
9-60
COPILOT’S FLIGHT INSTRUMENT PANEL LIGHTS
SYSTEM WITHOUT 17 AND 74
Description
The copilot’s flight instrument panel lights system
contains a CO-PILOT FLT INST LTS control,
autotransformer, variable resistor, and lamps to light
the instruments and the RAD ALT dimming panel.
Shield lights illuminate the following instruments: clock,
horizontal situation indicator (HSI), rate of climb, turn
and slip, airspeed, and course indicators. Postlights
illuminate the dual engine torquemeter. The system also
provides 26 vac to the integral lamps in the VGI and 5
vac to the integral lamps in the AIMS altimeter, radar
altimeter, and rotor tachometer.
Operation
Power for the system comes from No. 1 26 vac lighting
transformer. When COPILOT INSTR LIGHTING circuit
breaker is closed, 26 vac is applied to the CO-PILOT
FLT INST LTS control, which is used to vary the
brightness of the lamps. Should a loss of 26 vac occur
on the No. 1 26 vac bus, the lamps for the turn and
slip indicator can be controlled through the secondary
cockpit lighting circuit.
9-193
