In the density-altitude scenario, what was the length of the gravel strip?

• A. 2,100 feet
• B. 1,800 feet
• C. 1,500 feet
• D. 3,000 feet

Answer: (A)

In a density-altitude scenario, the air is thinner, so the wing generates less lift at a given speed and any tow or winch system has to work harder to accelerate. A gravel surface also adds drag and rolling resistance, making acceleration to takeoff speed even slower. Because of these effects, more runway is needed to reach the required speed and achieve a safe liftoff. Among the options, the one that provides enough distance to accelerate, lift off, and clear the strip under these conditions is the longer gravel strip listed. The shorter options wouldn’t give adequate margin with the reduced performance inherent to density altitude and a gravel surface.