Fox is a
brevity code used by
NATO pilots to signal the simulated or actual release of an
air-to-air munition or other combat function.
Army aviation elements may use a different nomenclature, as the nature of
helicopter-fired weapons is almost always
air-to-surface. 'Fox' is short for 'foxtrot', the
phonetic designation for the letter 'F', which is short for 'fire'. The radio call announcing that a weapon has been fired is intended to help avoid
friendly fire, cuing other pilots to ensure that they do not maneuver into the path of harm.