Balanced Field Takeoff - Regulatory Background

Regulatory Background

Aviation regulations, especially FAR 25 and CS-25 (for large passenger aircraft) require the takeoff distance and the accelerate-stop distance to be less than or equal to the available runway length, both with and without an engine failure assumed. The speed below which takeoff must be aborted upon engine failure is called V₁. On longer runways a pilot can nominate a V₁ within a range, but where the runway length is no longer than the balanced field length only one value for V₁ will exist.

Landing and Takeoff Performance Monitoring Systems are devices aimed at providing to the pilot information on the validity of the performance computation, and averting runway overruns that occur in situations not adequately addressed by the takeoff V-speeds concept.

Using the balanced field takeoff concept, V₁ is the maximum speed in the takeoff at which the pilot must take the first action (e.g. reduce thrust, apply brakes, deploy speed brakes) to stop the airplane within the accelerate-stop distance and the minimum speed at which the takeoff can be continued and achieve the required height above the takeoff surface within the takeoff distance.