Singapore legislation
Regulation 120
of Air Navigation (135 — Commercial Air Transport by Helicopters and Small Aeroplanes) Regulations 2018
Regulation 120
Ground proximity warning system
Subregulation 1
An AOC holder must ensure that every relevant aircraft that corresponds to one of the following descriptions is equipped with a ground proximity warning system which has a forward looking terrain avoidance function:
a turbine-powered aeroplane with an MCTOM exceeding 5,700 kg, or with an MAPSC exceeding 9;
a turbine-powered aeroplane with an MCTOM not exceeding 5,700 kg and an MAPSC exceeding 5 but not exceeding 9;
a piston-engined aeroplane with an MCTOM exceeding 5,700 kg, or with an MAPSC exceeding 9;
a helicopter with an MCTOM exceeding 3,175 kg, or with an MAPSC exceeding 9, and which is to be operated in accordance with the Instrument Flight Rules.
Subregulation 2
The ground proximity warning system required to be installed in an aeroplane described in paragraph (1)(a) —
must provide an automatic and distinctive warning to the flight crew when the aeroplane is in potentially hazardous proximity to the earth’s surface; and
must provide warnings for all of the following circumstances:
excessive descent rate;
excessive terrain closure rate;
excessive altitude loss after take‑off or go‑around;
unsafe terrain clearance while not in the landing configuration:
gear not locked down;
flaps not in a landing position;
excessive descent below the instrument glide path.
Subregulation 3
The ground proximity warning system required to be installed in an aeroplane described in paragraph (1)(b) or (c) —
must provide an automatic and distinctive warning to the flight crew when the aeroplane is in potentially hazardous proximity to the earth’s surface; and
must provide warnings for all of the following circumstances:
excessive descent rate;
excessive altitude loss after take‑off or go‑around;
unsafe terrain clearance.