40.4 Extended Diversion Time Operations (EDTO)

40.4.2 Explain the concept of EDTO.

EDTO enable properly certified aircraft, operated by appropriately qualified crew, to fly further than a threshold time (e.g. 60 minutes) at One Engine Inoperative (OEI) cruise speed in still air and ISA conditions.

Air transport aircraft are required to remain within a safe distance to suitable alternate aerodromes.

The distance is normally expressed as a time – i.e. 60min – which is worked out using the worse case situation – in a multi engine, pressurised aircraft – the worse case is one-engine out and depressurised.

When this occurs the aircraft would fly slower and burn more fuel than normal. 

When flight planning, aircraft have to stay within this certain distance from a suitable diversion aerodrome.