Aircraft Lighting Systems

• Lighting helps reduce mid-air collisions, as per ICAO Chicago Convention Annex 8.
• Exterior lights include navigation, anti-collision, landing/taxi, wing leading edge, and strobe lights.

Navigation Lights

• Also known as position lights, located on wing tips and tail.
• Color-coded to indicate an aircraft's direction:
• Red: Left (port) side.
• Green: Right (starboard) side.
• White: Tail.
• White tail lights are also located behind the wing tip colored lights
• Commercial aircraft use multi-bulb navigation lights for redundancy.
• The minimum requirement for night operations with multi-bulb wing tip and tail lights includes one stationary red wing tip bulb, one stationary green wing tip bulb, and one stationary white tail light at each wing tip position.

Anti-Collision Beacon

• A flashing red beacon producing 40-100 flashes/minute.
• Visible from all directions within 30 degrees above/below the horizontal plane.
• Can be located on top/underside of the fuselage or on the vertical stabilizer.
• Three types: Rotary reflector, rotating bulb, and red strobe.
• Rotary reflector type is common in light aircraft, using a small motor and gear train to rotate reflector around a stationary bulb.

Strobe Lights

• Anti-collision lights that look similar to other anti-collision lights
• Use a high-intensity strobe light tube under a red lens in place of incandescent bulbs
• High-intensity flash generated from a strobe unit with a high voltage.
• White strobe lights are on each wing tip and sometimes tail, flashing white light 50-80 times/minute.
• Power packs can be manufactured to supply one, two or three lights, and must be interconnected so the lights are synchronized to flash at the same time
• Switch on before takeoff and switch off after exiting the runway on landing to indicate that the aircraft is in flight
• Strobe tube assembly consists of a Xenon flash tube filled with gas, as well as a cathode, anode and an external trigger electrode

Handling precaustions

• Disconnect power for five minutes before any maintenance is performed.
• Do not look directly at an operating strobe
• Do not operate strobes during refuelling operations
• Do not touch the tube assembly with bare hands.

Landing Lights

• Cooled by airflow during flight, minimize ground testing to prevent overheating.
• Bulb types: Pre-focused in parabolic reflector, or sealed beam.
• Tighten retaining fixtures evenly to prevent cracks and filament burnout.
• Some extend to one position via a cam and micro-switch, others to multiple pre-set positions.
• Some landing lights also function as taxi lights and some are integrated into flap fairings.
• Manual selection landing lights have a spring-loaded EXTEND-OFF-RETRACT switch that allows the crew to stop the light at any angle
• Must be cleaned with lead-free spirit
• Two types of landing lights: fixed or retractable
• Retractable landing lights can be extended to one or more positions via a small split field rotary actuator and a gear train.

Quartz Halogen Bulbs

• Used in taxi, landing, and floodlights.
• Quartz envelopes withstand higher temperatures.
• Offers longer filament life and produces more light
• Clean with lead-free spirit if handled

Taxi Lights

• Typically fixed to the nose landing gear for directional beam.
• Electrical circuit is the same as for fixed landing lights.
• Use three switches on the P5 panel to control the taxi and runway lights, one switch for the nose gear taxi light and one switch of each runway turnoff light
• Avoid operating for more than five minutes to prevent decreased lamp life

Ice Detection/Wing Leading Edge Lights

• Mounted in the side of the fuselage to allow the pilot to visually detect ice formation on the wing leading edge. Typically a sealed beam lamp is used.
• Basic ON-OFF switch control.

Cabin Lighting

• Illuminates the main cabin, located in the ceiling or overhead lockers
• Modern aircraft use fluorescent lamps and indirect lighting
• Controlled from the flight attendant station.
• Larger aircraft may have multiple control units for different sections.
• Powered by the ground service bus.

Cabin Window Lighting

• Used to improve lighting of the seating area.
• Fluorescent tubes are fitted in parallel, using a ballast unit instead of a fluorescent starter.
• Controlled from the flight attendant station, typically independently of other cabin lighting.

Passenger Advisory Signs

• Used to advise passengers and cabin crew of safety requirements.
• E.g. FASTEN SEAT BELTS, NO SMOKING, TOILET OCCUPIED-VACANT, RETURN TO SEAT.
• Illuminated by electroluminescent lighting or incandescent globes.
• Controlled with switches on the flight deck, or automatically:
  • When the landing gear lever is placed in the ‘DOWN’ position
  • When a flap selection is made
  • Cabin decompression

Lavatory Lighting

• Lavatory OCCUPIED-VACANT sign uses a circuit-breaker, switch, and lights.
• Door latch activates a micro switch, which closes the circuit to illuminate occupied and lavatory interior lighting
• Extinguishes when door is unlocked.

Passenger Reading Lights

• Restrict light to the reading area.
• Individually switched and powered from a circuit-breaker.
• Some aircraft reading lights are controlled from the passenger seats with electronic modules that are located under the seats.

Flight Compartment Lighting

• Sufficient to illuminate all controls, switches and instruments with uniform intensity
  • Without shine or distract the flight crew
• Modern aircraft are usually white, some older aircraft may have red lighting
• Five main types of cockpit lighting:
  • Integral lighting
  • Post or Pillar lights
  • Trans-illuminated panels
  • Floodlights
  • Utility or wander lights

Integral Instrument Lighting

• Illuminates flight deck instruments.
• Used for intensity control in glass cockpits or standby analogue instrumentation illumination.
• Allows pilots to control their own instrument lighting, but Pilot in Command controls the center instrument panel (usually engine and standby instruments)
• The light is diffused on the dial via several smaller globes positioned around the dial in a plastic ring.

Post or Pillar Lights

• Used in areas where there is insufficient light from other sources.
• Have a hood which directs the light down and across a 90 degree arc _Usually they are screwed to the instrument panel _The hood can be adjusted to ensure the light illuminates the correct area (often via a 360 degree rotation)

Trans-illuminated Panels

- Also known as indirect lighting

• Made from transparent plastic or Perspex that is painted with a translucent white, then an opaque black or grey paint and are engraved with inscriptions, with light shining through them
• Most commonly used to display system controls and switching (e.g hydraulic panel, electrical panel etc.) and operates through a dimmer unit controlled by switches in the flight compartment
• The minimum amount of bulbs, with a high surface area of panelling

Floodlights

• Illuminates large areas such as side and center consoles, floors, and the circuit-breaker panel and main instrument panels _ Usually fluorescent tubes, or incandescent bulbs with a dimming facility _These are usually controlled through a switch accompanied by dimmer control unit

Utility or Wander Lights

• Act as floodlights, map reading lights, or emergency lights to replace a failed light system and are often powered from a hot battery bus so they can be used as emergency lighting in the event of a total power failure
• Power source being the use of a hot battery bus
• Flexible chord, mounted in a ball clip socket
• Some have two lenses _One being two colors: White and Red _The other with controls the switching and intensity of the light

Cargo Compartment Lights

• Fitted in the aircraft’s cargo compartments _They can be fluorescent or incandescent lights and are simple light systems
• Most Commercial aircraft cargo lighting systems operate trough a micro-switch that is located in the door of the cargo compartment, so that: When the door is closed, regardless of the light switch being selected on or off they extinguish, and, when the cargo door is opened, the cargo compartment lights are switched on through the normal light located int he cargo door opening

Loading Lights

• Illuminates apron areas where cargo and baggage loading takes place _ Simple light systems
• The controls for this lights are often usually outside of the aircraft
  • In some aircraft this is controlled by a micro-switch in the aircraft’s landing gear, which turns on the lights when the weight of the aircraft has been places on the wheels

Emergency Lighting

• Marks all exits and illuminates the cabin with enough light for the crew to operate emergency equipment and guide passengers to safety, without outside lighting _The intensity and position requirements of these lights are detailed in relevant ICAO and civil aviation regulations
• Emergency Exit Lights _Each light includes: - EXIT-labeled lights, plus a white window lighting the exit

Modern Aircraft

• Most commonly have an independent nickel cadmium battery pack
• Most can use a DC electrical system in order to charge the battery from the aircraft

Key Considerations

• Primary control for lighting is a single guarded 3 position switch in the flight compartment labelled OFF-ARMON, as well an ON-OFF switch is installed on the light attendants light panels in the cabin
• For aircraft Parking _Ensure that the emergency light's switch is switched off/ in the OFF setting before turning off the aircraft's electrical power because failure to do so will illuminate the emergency lights (this could cause the emergency light battery packs to be exhausted and cause rendering of the aircraft in an unserviceable setting)

Operational Requirements

• For night operations there must be in full operative for the emergency cabin lights in place
  • Inoperative individual aisle lights may be implemented, so long that they come into compliance with approved minimum regulatory required- lighting levels

Portable Emergency Lights

• In the Fixed lights on the exits, there are portable emergency exit lights that are positioned there _ These lights can be detached/ used a torch due to having an internal battery pack

Troubleshooting

• Main fault: Bulb Failure. Check multi-bulb lights fully.
• intensity Controls systems should be checked through their full intensity range
• Illumination with come from passenger cabin isles ( with the use of the emergency lights), exit signs, interior and exterior areas of the exits doors/ escape sides, and overwing areas _The light is turned on or with the occurance of (if an electrical power occurs/ when the passenger cabin or flight dick turns it on

Warning and Caution Lights

• They are defined as ‘attention getters’ and are used to alert crew members with system failures or abnormalities
• Their light colors: _ Red, to highlight a condition that affect the safety of the aircraft. _Amber to highlight a system abnormality that requires corrective action for flight crew (this can get cancelled by pressure from the master switch light)
• Conditions that require illumination of these lights: _ Overspeed, Autopilot disconnect, Fire, Configuration is set to take-off (or landing), Cabin altitude, and Ground proximity related warnings and windshear

Questions about aircraft lighting systems. This includes anti-collision lights, strobe lights, taxi lights and runway turnoff lights. Also covers ground service bus and cabin lighting.