Singapore legislation
Regulation 111
of Air Navigation (121 — Commercial Air Transport by Large Aeroplanes) Regulations 2018
Regulation 111
Oxygen indicators
An AOC holder must ensure that every large aeroplane to be operated at an altitude above flight level 100 —
(a)
is equipped with a means of indicating to the flight crew —
(i)
whether the passenger oxygen system is activated;
(ii)
if the oxygen system is supplied by a gaseous system, the amount of breathing oxygen available in each source supply; and
(iii)
if the aeroplane is a pressurised aeroplane, by visual or aural warning, when the cabin pressure altitude exceeds 10,000 ft; and
(b)
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.