Singapore legislation
Regulation 109
of Air Navigation (135 — Commercial Air Transport by Helicopters and Small Aeroplanes) Regulations 2018
Regulation 109
Pressure-altitude reporting transponder
Subregulation 1
An AOC holder must ensure that every small aeroplane is equipped with a pressure‑altitude reporting transponder —
which operates in accordance with the provisions of Volume IV of Annex 10 to the Chicago Convention;
which is capable of operating in Mode S;
which has a data source that provides pressure‑altitude information with a resolution of 7.62 m (25 ft) or better; and
which is provided with an airborne or on‑the‑ground status of the aeroplane when that aeroplane is equipped with an automatic means of detecting such status.
Subregulation 2
An AOC holder must ensure that every helicopter is equipped with a pressure‑altitude reporting transponder which operates in accordance with the provisions of Volume IV of Annex 10 to the Chicago Convention.