4.2 Lighting & Electrical Systems

Where cabin power comes from

The final row is the crucial one for cabin crew. Emergency lighting does not depend on the aircraft's main electrical system. That independence is the whole point: an accident that severs the electrical system must not extinguish the escape path.

Normal cabin lighting

Cabin lighting is normally selectable by zone with bright, dim and night settings, plus separate control of ceiling wash, sidewall lighting, entry and galley lighting, and reading lights.

Two operational rules matter more than the switch layout:

1. Dim the cabin for take-off and landing at night. Human dark adaptation takes several minutes. If an evacuation begins from a brightly lit cabin into a dark night, occupants are effectively blind at the moment they most need to see. Dimming before departure and before landing means eyes are already adapted.
2. Window blinds up for take-off and landing. Raised blinds let crew assess conditions outside the aircraft before opening a door, admit external light during an evacuation, and let rescuers see in.

Emergency lighting

Emergency lighting is a certificated system with several elements working together:

Arming and activation. The system is normally armed from the attendant panel or flight deck before flight, and once armed it activates automatically on loss of normal electrical power, and on impact where an inertia switch is fitted. It can also be switched on manually. The control is generally guarded to prevent inadvertent operation.

Duration. Emergency lighting batteries are certificated to power the system for a defined period after activation — long enough for an evacuation and the immediate aftermath, not indefinitely. That is one reason evacuation is completed rather than paused.

Pre-flight checks at each station include confirming the emergency lighting is armed, that no fault caption is illuminated, that exit signs and locators are lit as required, and that floor proximity marking is complete and unobstructed. Missing or damaged escape path marking is a defect for engineering, and bags left in the aisle that cover the marking are a defect cabin crew fix themselves.

Exterior and other lighting

• Navigation lights — red on the left wingtip, green on the right, white at the tail, on whenever the aircraft is operating.
• Anti-collision beacons — red, switched on before engine start and off after shutdown, which is why the beacon is a useful cue that engines are about to run.
• Strobes — high-intensity white lights normally selected for the runway and in flight.
• Landing and taxi lights, wing inspection lights — the latter allow the wing to be examined in darkness, useful when checking for contamination or damage.
• Logo lights — illuminate the tail fin.

Electrical smoke, sparks and burning smells

Electrical faults are the origin of a significant share of in-flight fires, and many begin in cabin equipment: seat power supplies, in-flight entertainment boxes under seats, galley equipment and passenger devices plugged into cabin outlets.

Immediate actions:

1. Remove the power. Switch off and, where the operator's procedure permits, isolate the item — for example by pulling the galley or seat power switch, or asking the flight deck to remove power from the affected system. Do not attempt to pull circuit breakers unless the operator's procedure authorises it.
2. Notify the flight deck immediately with a structured report giving location and description.
3. Treat it as a fire until proved otherwise. Bring the extinguisher and PBE to the location before you need them.
4. Do not use water on an energised electrical item. Halon or another approved agent is used until the item is confirmed de-energised; water may then be used on any residual Class A materials such as seat foam and covers.
5. Watch for re-ignition. A continuous firewatch is maintained on the affected area until landing.
6. Report and preserve. The item is left in place where safe, the event is reported, and the affected equipment is entered in the technical log so that engineering can trace the fault.

A burning smell with no visible source is not a reason to wait. Smoke and fumes in a cabin can double in a very short time, and the earliest possible report gives the flight crew the option of a diversion while they still have plenty of choices.