Ground proximity warning system
122.—(1)  An AOC holder must ensure that every aeroplane (turbine‑powered or piston‑engined) with an MCTOM exceeding 5,700 kg or an MAPSC exceeding 9 is equipped with a ground proximity warning system which has a forward‑looking terrain avoidance function.
(2)  The ground proximity warning system required to be carried by a turbine‑powered aeroplane in accordance with 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
(b)must provide warnings for all of the following circumstances:
(i)excessive descent rate;
(ii)excessive terrain closure rate;
(iii)excessive altitude loss after take-off or go-around;
(iv)unsafe terrain clearance while not in the landing configuration;
(A)gear not locked down;
(B)flaps not in a landing position;
(v)excessive descent below the instrument glide path.
(3)  The ground proximity warning system required to be carried by a piston-engined aeroplane in accordance with 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
(b)must provide warnings for all of the following circumstances:
(i)excessive descent rate;
(ii)excessive altitude loss after take‑off or go‑around;
(iii)unsafe terrain clearance.