reduced thrust, resulting in the balanced field length again being equal to the runway length available. Factors affecting the balanced field length include: the mass of the aircraft – higher mass results in slower acceleration and higher takeoff speed engine thrust – affected by temperature and air pressure, but reduced thrust can also be deliberately selected by the pilot density altitude – reduced air pressure or increased temperature increases minimum take off speed aircraft configuration such as wing flap position runway slope and runway wind component runway conditions – a rough or soft field slows acceleration, a wet or icy field reduces braking Technology Calculation of the balanced field length traditionally involves relying on an expansion program model, where the various forces are evaluated as a function of speed, and step-wise integrated, using an estimate for V1. The process is iterated with different values for the engine failure speed until the accelerate-stop and accelerate-go distances are equal. This process suffers from the inherently slow and repetitive approach, which is also subject to round-off errors if the speed increment between the steps is not carefully selected, which could cause some issues in first principle aircraft performance models provided to airlines for day-to-day operations. Alternate approaches using a more mathematically complex but inherently more accurate and faster algebraic integration method have however been developed. Landing and Takeoff Performance Monitoring Systems are devices aimed at providing the pilot with 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. See also Flight planning V speeds Takeoff References Types of take-off and landing