NavigationFlight Planning
Equi-time Point (ETP)
The equi-time point (ETP) is a calculated geographical point along a flight route where the time required to continue to the destination is exactly equal to the time required to return to the departure point. It is calculated using the planned track, true airspeed, and forecast wind components.
Key Points
- •Also known as the critical point (CP).
- •In the presence of wind, the ETP shifts towards the headwind destination — that is, closer to the destination when facing a headwind to the destination.
- •Used to determine the quickest diversion option during abnormal operations.
Exam Relevance
Calculating the ETP is a critical flight planning skill for deciding the safest and fastest course of action during an in-flight emergency.
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