Performance values take into account the threshold is crossed at ____ ft. at ____.

Performance values take into account the threshold is crossed at ____ ft. at ____.

• A. 50 ft; Vref
• B. 40 ft; Vref
• C. 60 ft; Vref
• D. 50 ft; Vapp

Answer: (A)

Performance values for landing take into account a standard threshold crossing height and the landing reference speed. The threshold crossing height is the height at which you cross the threshold on the final approach, and for a typical standard approach it’s 50 feet. The speed used for calculating landing performance is Vref—the reference landing speed in landing configuration—which reflects weight and configuration and is the speed you aim to be at touchdown. Because performance data are based on crossing the threshold at 50 ft while in the landing configuration at Vref, that pairing is the correct one. Using a different crossing height (like 40 or 60 ft) or using Vapp (approach speed) wouldn’t align with how the performance charts are generated for landing.

Performance values for landing take into account a standard threshold crossing height and the landing reference speed. The threshold crossing height is the height at which you cross the threshold on the final approach, and for a typical standard approach it’s 50 feet. The speed used for calculating landing performance is Vref—the reference landing speed in landing configuration—which reflects weight and configuration and is the speed you aim to be at touchdown. Because performance data are based on crossing the threshold at 50 ft while in the landing configuration at Vref, that pairing is the correct one. Using a different crossing height (like 40 or 60 ft) or using Vapp (approach speed) wouldn’t align with how the performance charts are generated for landing.