ATPL Online question bank
Question 1 of 14 Number: 12208

Aircraft equipped with red anti-collision lights may display them:

  1. outside the daylight-period in flight, but not on the ground when being towed.
  2. outside the daylight-period at engine-start. During the daylight period this procedure is not applicable.
  3. on the ground when the engines are running.
  4. while taxiing, but not when being towed.

Fixed wing aircraft must have at least one anti-collision light which may be either red or white.

If fitted with a white anti-collision light, this may be displayed for engine start but it must be displayed during taxiing. (This rule has possibly come about because a white anti-collision light has a 'strobe-style' effect and could be distracting for the start crew.)

If fitted with a red anti-collision light then this must be displayed for engine start and taxiing.

(Helicopters only have red anti-collision lights!)