Under Part 135, a turbojet must be able to stop within what percentage of the runway's effective length?

• A. 60%
• B. 70%
• C. 80%
• D. 50%

Answer: (A)

Stopping performance at Part 135 is about guaranteeing a built‑in safety margin for turbine-powered aircraft. The rule sets that a turbojet must be able to stop within 60 percent of the runway’s effective length. This ensures there’s ample room to decelerate and come to a standstill from approach or after an aborted takeoff, even when conditions aren’t perfect or when operating at higher weights.

The “effective length” isn’t just the physical length of the strip; it’s the usable distance after accounting for factors like displaced thresholds, slopes, and other runway limitations that reduce where you can actually stop. In practice, pilots and operators calculate the stop distance (or accelerate-stop distance) for the planned weight and configuration and verify that it fits within 60% of the runway’s effective length. If it wouldn’t, they adjust by choosing a longer runway, reducing weight, or altering the approach/landing profile to maintain that safety margin.