FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceMedium
A turbojet is being dispatched to a destination airport where the actual landing distance available is 8,000 feet. Per the Part 121 60 percent rule, what is the maximum landing distance the aircraft may require for the destination to be legal for dispatch?
- A4,000 feet
- B6,400 feet
- C4,800 feet
- D3,200 feet
Show answer & explanationAnswer & explanation
Correct answer: C. 4,800 feet
The 60% rule requires that the landing distance required not exceed 60% of the landing distance available. Calculation: 8,000 ft × 0.60 = 4,800 feet.
Why the other options are wrong
- A. 4,000 feet uses exactly half the runway, not the correct 60% factor.
- B. 6,400 feet uses 80% of the runway, exceeding the regulatory limit.
- D. 3,200 feet uses 40% of runway length, not the 60% rule.
60% Landing Distance Rule
For turbojets under Part 121, the landing distance required at the destination (and alternate) may not exceed 60% of the landing distance available on a dry runway.
- Applies to turbojet aircraft under 14 CFR 121.195
- Landing distance required ≤ 60% of landing distance available
- Wet runway rules may require additional distance beyond the dry calculation
Memory trick: 'Six of ten, use it, then you're in.'