FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceHard
A dispatcher is planning a flight for a twin-engine aircraft operating under a 180-minute ETOPS authorization. What does this 180-minute diversion time represent?
- AThe total flight time allowed between scheduled maintenance checks
- BThe maximum flying time to an adequate alternate airport at one-engine-inoperative cruise speed in still air
- CThe maximum time the aircraft can remain airborne with both engines operating normally
- DThe maximum time ATC will hold the flight before rerouting
Show answer & explanationAnswer & explanation
Correct answer: B. The maximum flying time to an adequate alternate airport at one-engine-inoperative cruise speed in still air
ETOPS diversion time (e.g., 180 minutes) defines the maximum distance from an adequate alternate airport, expressed in flying time at the approved one-engine-inoperative cruise speed in still-air conditions, that the aircraft may operate along its route.
Why the other options are wrong
- A. Maintenance interval timing is a separate concept from ETOPS diversion time.
- C. This does not describe normal two-engine operation time.
- D. ATC holding time is unrelated to ETOPS authorization.
ETOPS Diversion Time
ETOPS diversion time is the maximum time, in minutes, that a twin-engine aircraft may operate from an adequate alternate airport based on one-engine-inoperative cruise speed in still air.
- Common authorizations: 60, 120, 180, 207, 240 minutes
- Based on OEI cruise speed, not normal cruise speed
- Defines the ETOPS area of operation on a route
Memory trick: '180 means never more than 3 hours from safety on one engine.'