ATA 33: Airbus A320 (Technical Notes)

The A320 ATA 33 Technical Notes provide brief and to-the-point information about the Airbus A320 Lighting System, including its components and their functions. ATA Chapter 33 deals with the lighting system of an aircraft that provides external and internal illumination.

A320 LIGHTING SYSTEM

The Airbus A320 aircraft lighting system provides illumination inside and outside of the aircraft. The system comprises:

Cockpit lighting
Cabin lighting and signs
Emergency lighting
Exterior lighting
Cargo and service compartment lighting

COCKPIT LIGHTING

General cockpit lighting by – Dome Light.
An annunciator light test switch permits illumination of all annunciators and therefore check of all lights.

ANNUNCIATOR LIGHT TEST & DIMMING

A switch with 3 positions (DIM, BRT, TEST).
Annunciator Light Control Box – 70 VU
- Interface Boards (Board means PCB, usually called Card) for different panel –
  - Overhead panel
  - Pedestal
  - Main Panel
  - Glareshield
Test switch > Annunciator Light Control Box > p/b
Power supply for p/b > through – Terminal Block
DIM – voltage will be same and current will be less.

CABIN LIGHTING AND SIGNS

cabin lighting system includes –
- Passenger Cabin Lighting – controlled through CIDS.
- Entrance Area Lighting
- Lavatory Lighting
- Passenger Reading Lights
- Lavatory Lighted Signs
- Cabin Attendant Work-Lights
The lighted signs NO SMOKING, FASTEN SEAT BELT and RETURN TO SEAT (NS/FSB/RTS) are part of the CIDS.
Tubelight – Fluorescent lamp
- Advanced integrated ballast unit
CIDS gives up to 6 pre-programmed lighting scenarios – assigned in the Cabin Assignment Module (CAM).

EMERGENCY LIGHTING

Control by EMER EXIT LT switch in the cockpit.
3 position switch > ON/ARM/OFF.
- ON – all cabin emergency lights are on.
  - Lights are supplied from the DC essential busbar or from the EPSU batteries (if there is a DC essential busbar failure).
- ARM – Automatic Mode.
- OFF – cabin emergency lighting system is off.
Also can be controlled by EMERG ON p/b installed on the FAP.
Emergency Power-Supply Units (EPSU) – total 4
Emergency lights are installed in the cabin and on the exterior fuselage for overwing emergency exits.
EPSU – supply the following lights:
- Exit signs lights,
- Cabin emergency lights,
- Seat mounted emergency lights and exit location lights,
- Wall mounted emergency exit location light,
- Wall mounted exit marking sign,
- Wall mounted emergency exit,
- Wall mounted emergency light,
- Escape slide lights,
- Over-wing emergency lights,
- Lavatory auxiliary lights,
- Escape hatch-handle lights.
EPSUs convert 28V DC into 6V DC to operate their associated lights. An internal 6V DC battery in each EPSU is charged continuously when the ESS SHED BUS is energized and the system is not activated.
EPSU
- Supply power for at least 10 minutes.
- BITE – Each EPSU has a test circuit.
  - EPSU SYStem TEST
  - EPSU BATtery CAPacity TEST – duration of this test is around 3 hours.
Photoluminescent Floor Path-Marking-System – self-luminescent, charged by cabin lights.

EXTERIOR LIGHTING

Taxi and Takeoff Lights
- Provide illumination of the runway and the taxiway.
- Two lights – TAXI & TO
- 3 position switch
  - TO position – Taxi and Takeoff lights
  - TAXI position – Only Taxi light
  - OFF position – All light off
- Both lights are on, only if the NLG is downlocked (signal from LGCIU 2).
- Incandescent lamp technology or halogen lamp technology ///
  or LED technology.
Runway Turnoff Lights
- Provide illumination of the lateral areas of the runway.
- Two lights – LH & RH
- Single-filament lamps (or halogen lamps) / or LEDs
- Both lights are on, only if the NLG is downlocked (signal from LGCIU 2).
Wing and Engine Scan Lights
- illuminate the engine air intakes and the wing leading edges.
- to show if ice is accumulating there.
- Two lights – LH & RH
Navigation Lights
- indicates the aircraft position and direction
- dual navigation light system
- 3 position switch – 1, 2, OFF
- LED technology lights
- 1 Red color light – LH wing-tip (fwd facing)
- 1 Green color light – RH wing-tip (fwd facing)
- 1 White color light – tail cone at the extreme aft of the aircraft (rearward-facing)
- LED navigation lights are fitted with Near End-Of-Life (NEOL) indication.
Landing Lights
- to illuminate the runway when the aircraft lands at night.
- Two Lights (LH & RH) – each has a separate switch (3 position).
  - ON – Extends + ON
  - OFF – OFF but extended
  - RETRACT – Retracts
- They can be extended at all aircraft speeds.
- Halogen technology / LED technology.
- ECAM memo message – displays “LDG LT” in green, if one landing light is extended.
Anti-Collision Lights (Beacon Lights)
- The aircraft recognition lighting system is used as a visual aid to other aircraft and thus prevents a possible collision.
- 2 anti-collision lights – top & bottom
- Anti-collision light gives a red high-intensity light that flashes.
- controlled by the BEACON control switch.
- Flash-tube technology or LED technology
- Anti-collision lights (which do not turn) – Anti-collision lights have a flash tube that flashes at a rate of 55 plus or minus five flashes per minute. Each light gives 360 degrees of horizontal diffusion and 75 degrees of vertical diffusion.
- The beacon lights operate alternately in synchronization with the strobe lights.
- Power supply through PSU (Power Supply Unit) – to generate high voltage. Because Beacon Lights required more power to operate.
- LED anti-collision lights have the Near End Of Life (NEOL) indication.
Strobe Lights
- 3 strobe lights – 2 at each wing tip and 1 on the tail cone.
- Strobe light gives a white high-intensity light that flashes.
- controlled by the STROBE control switch – 3 position (on/auto/off).
- strobe lights come on automatically when the main gear strut is not compressed (LGCIU 2) – Auto Mode.
- ECAM memo message – “STROBE LT OFF ” in green is displayed if the strobe lights are set to OFF and aircraft in flight.
- are synchronized and operate alternatively with the beacon lights.
- Power supply through PSU (Power Supply Unit) – to generate high voltage. Because Strobe Lights required more power to operate.
- Flash-tube technology or LED technology
- Strobe lights have flash tubes that flash at a rate of 55 plus or minus five flashes in one minute.
- LED strobe lights flash at a rate of 60 +/- 5 flashes per minute.
- LED strobe lights are fitted with Near End-Of-Life (NEOL) indication.

Precaution –
- Do not remove a strobe light for at least 10 minutes after you de-energize the electrical circuits. The high voltage electrical current in the capacitor of the strobe light is dangerous.

Logo Lights
- They light up the airline’s logo on the fin.
- Two logo lights – LH & RH
- 3 position switch – controls the logo lights together with navigation lights.
- Logo lights come on automatically with the NAV1(NAV2) light during the subsequent flight phases: Taxiing, Takeoff, and Landing.
- Taxiing signal from – LGCIU 2 (strut compress)
- Takeoff/Landing signal from – SFCC 1 & SFCC 2 (flap position 15 degree)
- Filament-light technology or LEDs-light-unit technology
Switches on the overhead panel control the exterior lighting.

Near End-Of-Life (NEOL)

The NEOL indication is a blue LED light that flashes when the LED light is near degradation and you must replace it by a serviceable light before 1000 flight hours.
When the NEOL indication comes on, the LED light will not be extinguished after 1000 flight hours but its performance can decrease to less than the certification requirements.
The LED light assembly will become unserviceable after its pre-programmed life of 20000 hours.
LED Technology Lights are fitted with NEOL indication.
- Navigation Lights
- Strobe Lights

CARGO AND SERVICE COMPARTMENT LIGHTS

The cargo and service compartment lighting provides illumination and power outlets for maintenance purposes. The system comprises:

service area lighting for equipment and APU compartments,
air conditioning duct and accessory compartment lights,
FWD and AFT cargo compartment lights,
equipment compartment lights,
wheel well lighting.