Singapore legislation
Regulation 121
of Air Navigation (135 — Commercial Air Transport by Helicopters and Small Aeroplanes) Regulations 2018
Regulation 121
Significant weather detection
An AOC holder must ensure that every relevant aircraft that is used to carry passengers and is not a non‑pressurised aeroplane is equipped with an operative weather radar or other equipment capable of detecting thunderstorms or other potentially hazardous weather conditions whenever the aircraft is to be or is being operated —
(a)
in areas where such conditions may be expected to exist along the route in instrument meteorological conditions; or
(b)
at night.