Division (a) Helicopters on flights over water shall be equipped with a radio altimeter capable of emitting an audio warning below a pre-set height and a visual warning at a height selectable by the pilot, when operating:
United Kingdom
- (1)
out of sight of the land;
- (2)
in a visibility of less than 1 500 m;
- (3)
at night; or
- (4)
at a distance from land corresponding to more than three minutes at normal cruising speed.