Which source is used to determine takeoff distance, and what inputs are required?

• A. Takeoff distance is a fixed value for each aircraft and does not depend on conditions.
• B. Takeoff distance can be estimated from landing distance.
• C. Takeoff distance is taken from AFM/QRH performance data; inputs include weight, field elevation/pressure, temperature, wind, runway conditions, flap setting, and slope.
• D. Takeoff distance is determined after maintenance checks.

Answer: (C)

Takeoff performance is not a fixed number; it depends on the airplane’s configuration and the operating conditions. The official takeoff distance comes from the AFM/QRH performance data, which tabulates distances for different combinations of weight and environmental and runway factors. You use those charts by inputting weight, field elevation (and pressure), ambient temperature, wind, runway surface conditions, flap setting, and runway slope. Each factor changes how quickly the airplane can accelerate and achieve lift: heavier weight makes the ground roll longer; higher field elevation or higher temperature reduces air density, weakening thrust and lift; wind can shorten the takeoff distance with a headwind (or lengthen it with a tailwind); contaminated or wet runways reduce grip and extend distance; flap settings adjust lift and rotation speed; and slope matters because an uphill runway increases required distance while a downhill slope can shorten it. So the correct source is the AFM/QRH performance data, and the required inputs are weight, field elevation/pressure, temperature, wind, runway conditions, flap setting, and slope.