FAA Aircraft Dispatcher (ADX)Regulations (Part 121)Hard
A Part 121 two-engine turbojet airplane is preparing to depart from an airport where the weather is below the landing minimums specified in the certificate holder's operations specifications for that airport. Under 14 CFR 121.617, within what distance must a takeoff alternate airport be located?
- A30 minutes at normal cruising speed in still air
- B1 hour at one-engine-inoperative cruising speed in still air
- C2 hours at one-engine-inoperative cruising speed in still air
- D3 hours at normal all-engine cruising speed in still air
Show answer & explanationAnswer & explanation
Correct answer: B. 1 hour at one-engine-inoperative cruising speed in still air
14 CFR 121.617 requires that when takeoff weather is below landing minimums, a takeoff alternate be located within 1 hour of flight time at the one-engine-inoperative cruising speed in still air for airplanes with only two engines; airplanes with more than two engines are allowed up to 2 hours.
Why the other options are wrong
- A. 30 minutes is not the regulatory distance limit for takeoff alternates.
- C. 2 hours applies to airplanes with more than two engines, not two-engine airplanes.
- D. The rule specifies one-engine-inoperative speed, not normal all-engine cruising speed.
Takeoff Alternate Requirement (121.617)
When departure weather is below landing minimums, a takeoff alternate must be within 1 hour (two-engine airplanes) or 2 hours (more than two engines) at one-engine-inoperative cruising speed in still air.
- Applies when departure weather is below landing minimums
- 2-engine airplanes: 1 hour OEI cruise time limit
- 3+ engine airplanes: 2 hour OEI cruise time limit
Memory trick: 'Two engines, one hour; more engines, double the power.'