FAA Airline Transport Pilot (ATM)Aircraft Performance and Weight and BalanceMedium
Per 14 CFR Part 25 certification standards, after the airplane has completed flap retraction and reached a clean configuration with the critical engine inoperative, the airplane enters the final segment of the takeoff flight path and continues climbing to at least 1,500 feet AGL. For a two-engine airplane, what is the minimum required climb gradient during this final segment?
- A2.4%
- B1.2%
- C3.0%
- D0.5%
Show answer & explanationAnswer & explanation
Correct answer: B. 1.2%
The final (fourth) segment climb gradient requirement for a two-engine transport category airplane, with one engine inoperative in the clean configuration and maximum continuous thrust, is a minimum of 1.2%. This is lower than the second-segment requirement (2.4% for two engines) because thrust is reduced from takeoff to maximum continuous.
Why the other options are wrong
- A. 2.4% is the second-segment climb gradient requirement, not the final segment.
- C. 3.0% is not a Part 25 climb gradient minimum for this segment.
- D. 0.5% is not a certification climb gradient standard.
Final (Fourth) Segment Climb
The portion of the one-engine-inoperative takeoff flight path from clean configuration acceleration to 1,500 feet AGL, flown at maximum continuous thrust.
- Two-engine minimum gradient: 1.2%.
- Occurs after flap retraction (third/acceleration segment).
- Uses maximum continuous thrust rather than takeoff thrust.
- Ends at 1,500 feet AGL, completing the net takeoff flight path.
Memory trick: First lifts, Second climbs steep, Third accelerates flat, Fourth finishes clean to 1,500 ft.