Description

Virtually all aircraft types are fitted with external lights of some description. The type, purpose and complexity of the lighting systems installed on the exterior of a particular aircraft vary in accordance with its size, role and normal flight environment. External lights, in general terms, serve one of three purposes:

• to make the aircraft more visible to other aircraft,
• to improve pilot visiblity during critcal phases of flight or
• to provide illumination for some other specific purpose.

Note that there is often overlap in the utility of some of the external lights. As an example, landing lights greatly improve a pilot's ability to see the runway during takeoff and landing but also enable the aircraft to be seen by ground personnel and by other airborne traffic.

Some of the lights of the first two categories are a regulatory requirement during hours of darkness. Minimum Equipment List (MEL) relief may be available under some circumstances.