Take-off power (aircraft)

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The starting power (English take-off performance , TOP) of an aircraft is an important for each aircraft type parameter based on aircraft weight be related Before every known need. It describes the flight performance of the aircraft in the take-off phase and should not be confused with the pure engine performance.

The starting performance depends on many factors. These include, among other things, the dead weight at take-off, the take-off speed, the selected engine power, but also environmental factors such as the height of the airport above MSL , the prevailing temperature, air pressure as well as wind direction and wind speed. Furthermore, factors of the infrastructure must be taken into account, such as the nature and condition of the runway (length, slope, surface, dry / wet / snow / ice, etc.) as well as obstacles inside and outside the airport area.

The basic data that are flown for each type of aircraft in the TOP test are contained in the flight manual in the form of graphics or in corresponding measurement sheets. This data, together with the current conditions on site, result in the take-off performance that an aircraft can provide. The calculations are made much easier today by using appropriate computer programs.

Technical considerations

The take-off performance is made up of three sub-areas, namely take-off, climbing, and freedom from obstacles. For each of these areas, a maximum weight is calculated with which the aircraft in the respective configuration meets the legal criteria. There are three values:

  • Field Limit : is made up of the available takeoff distance , available takeoff distance up to an obstacle clearance ( screen height ), available takeoff distance in the event of an engine failure before the decision speed . In order to achieve a high weight here, a high flap position and a long runway are recommended .
  • Climb Limit : is a legally prescribed minimum climbing gradient (after an engine failure) that is calculated without taking the wind into account. In order to achieve a high weight here, a low flap position is helpful.
  • Obstacle Limit : considers the obstacle situation in a corridor up to 900 m to the left and right of the intended flight path after an engine failure. This weight is maximized through a low flap position and the selection of a wind and obstacle-friendly runway .

The lowest of these three weights determines how heavy the aircraft can be at takeoff.


The legal requirements for commercial flights by European aircraft in the EU OPS are regulated, depending on their flight performance class . For private flights, it is sufficient to demonstrate compliance with the certification specifications according to EASA CS-23 or CS-25 .


  • Lush, KJ - Standardization of Take-Off Performance Measurements for Airplanes, Technical Note R-12 , AFFTC, Edwards AFB, California.
  • Anderson, John D., Jr. - Introduction to Flight, 3rd ed. , McGraw-Hill Book Company, New York, 1989.
  • Herrington, Russel M., Major, USAF, et al. - Flight Test Engineering Handbook , AF Technical Report 6273, AFFTC, Edwards AFB, California, 1966
  • Russell E. Erb - A Low Cost Method for Generating Takeoff Ground Roll Charts from Flight Test Data , Society of Flight Test Engineers (SFTE) 27th Annual Symposium, Fort Worth, Texas, November, 1966

Web links

  • EU OPS Section F (PDF # page = 99) Law on the commercial handling of European aircraft, section on flight performance in general