111. Oxygen indicators

An AOC holder must ensure that every large aeroplane to be operated at an altitude above flight level 100 —

is equipped with a means of indicating to the flight crew —

whether the passenger oxygen system is activated;

if the oxygen system is supplied by a gaseous system, the amount of breathing oxygen available in each source supply; and

if the aeroplane is a pressurised aeroplane, by visual or aural warning, when the cabin pressure altitude exceeds 10,000 ft; and

is equipped with a means of indicating to each user of an individual dispensing unit, whether the oxygen is being delivered to the dispensing unit.