Aircraft Lighting System Overview

External Lighting

• Navigation lights: mark aircraft extremities, provide position reference, and consist of red light on left wingtip, green light on right wingtip, and white light on tail
• Flashing lights: mark aircraft position
• Landing and taxiing lights: provide forward and lateral illumination for landing and taxiing in night or poor visibility conditions
• Wing illumination lights: illuminate wings for ice inspection
• Emergency lights: assist in passenger and crew evacuation in emergency landings

Navigation Lights

• Also called position lights
• Red on left wingtip, green on right wingtip, and white on tail
• Operate on 28V DC or 115V AC

Landing and Taxi Lights

• Provide illumination for landing and taxiing in night or poor visibility conditions
• 600W for landing and 250W for taxiing
• Two fixed lights on wing leading edges near fuselage and two retractable lights in outboard flap track fairing on Boeing 737 aircraft
• Retractable lights shine forward regardless of flap position
• Each light has two filaments mounted in tandem, pivoted on its own axis, and rotated by a motor

Wing Illumination Lights

• Two lights on each side of fuselage forward of wing leading edge
• Used for ice detection in flight and to illuminate immediate area on ground

Emergency Escape Slide Lights

• Four exterior lights illuminate escape slide areas for forward and aft entry and forward and aft service doors
• Additional four lights illuminate overwing escape doors and areas just aft of wing trailing edge

External Lighting Control Panel

• Normally located on the lower overhead panel

Internal Lighting

• Illuminates consoles/control panels, passenger compartments, and information signs
• Warning lights indicate system-operating condition
• Emergency lighting receives inputs from fault annunciators to illuminate master caution lights and master caution annunciators

Passenger Compartment Lighting

• Ceiling and window lights illuminate passenger compartment
• Entry and threshold lights provide lighting for doorways
• Other cabin lighting systems include lavatory lights, reading lights, passenger information signs, and attendant call system

Passenger Service Unit (PSU)

• Contains reading lights, fasten seat belt and no smoking signs, attendant call button, air conditioning fans, life vest storage, and oxygen mask storage

Reading Lights

• Each passenger has a reading light with a touch-control button on passenger panel to switch on or off
• Reading reset switch on attendant panel switches off all reading lights in one action
• When operated, reading lights supply is broken for 16 seconds only and remains off but ready for 'ON' selection

Attendant Call System

• Attendant can be called from each passenger station through 'ATT.CALL' touch button
• Action brings on a light in 'Area Call Lights Aft' and 'FWD' stations
• Chime on PA system also alerts the action
• Reset is achieved by a second touch at 'ATT CALL' switch
• Operation of a switch in either lavatory calls an attendant in similar fashion and identifies which lavatory the call was made from

Emergency Exit Lighting

• Automatically illuminates exit signs and egress paths when normal lighting system power is lost
• Powered by battery packs and located in flight and passenger compartments
• Includes external lights used to illuminate escape routes from doors and overwing hatches
• Floor proximity lighting provides visual guidance for cabin evacuation when all sources of cabin lighting above four feet is obscured by smoke

Emergency Lighting Operation

• Emergency lights (6V) are fed from battery packs trickle charged from aircraft main electrical system
• The system operates under three conditions:
  • OFF: battery packs are charged, 6V lights remain off even in main electrical power loss
  • ARMED: normal in-flight position, 6V lights operate only when main electrical power is lost
  • ON: battery packs are not charged, 6V lights operate even with main electrical power available