Not only does the operator or aircraft it operates have to satisfy certain requirements, so does the way in which a flight is planned and a certain route is flown. Before commencing flight, a flight plan has to be build and filed which describes the route of flight in detail. In case of an ETOPS approved flight plan, certain route segments and ETOPS points along the flight path should be determined. An ETOPS flight requires the determination of the ETOPS Entry Point (EEP), ETOPS Exit Point (EXP), ETOPS Critical Points (CP) and Points of Equal Time (PET).
- The EEP is located at one hour flying time from the last adequate airport prior to entering the ETOPS segment at the selected one-engine-out diversion speed schedule on the aircraft's outbound route. This point actually marks the beginning of the ETOPS segment.
- The EXP marks the end of the ETOPS segment and is marked by a point where the aircraft leaves the area exceeding 60 minutes flying time at the approved one engine inoperative speed from a suitable aerodrome for the last time on that particular route.
- The CP marks a point on the aircraft's flight path that is critical in terms of fuel. Usually the CP is the last PET within the ETOPS segment.
The PET's are points along the route, which are located at the same flying time from two suitable diversion airports. In general, these points are calculated either by a computerized flight planning system or graphically on a navigation chart.