Aircraft weight

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mobile aircraft scale

With aircraft weight are in the aviation a number of different definitions referred to in matters of aviation safety , to u by weight. Center of gravity determination and can be used in the fuel calculation.

Weight definition

Manufacturer's Empty Weight (MEW)

  • Manufacturer empty weight or absolute empty weight

The weight of the aircraft structure and parts necessary to fly.

Empty Weight (EW) / Operating Empty Weight (OEW) or Operating Weight Empty (OWE)

  • Empty weight or operating empty weight

The absolute empty weight (MEW) is supplemented by the permanently installed additional equipment (including kitchen equipment )

Basic Weight

  • The basis weight

Empty weight supplemented by hydraulic fluid and oil as well as residual fuel. The basis weight is the weight of the empty aircraft including all basic equipment and a specified amount of non-usable fuel and engine oil. For turbine aircraft and aircraft with a weight of up to 5.7 t, the basis weight can also include the weight of the entire engine oil.

Basic Operating Weight (BOW)

(Also Dry Operating Weight (DOW))

  • Basic or basic operating weight

Consists of basic weight and crew, hand luggage for the crew, drinking water, drinks for the passengers, normal equipment for passenger service that is normally on board. BOW is identical to the Dry Operating Weight (DOW) - dry operating weight .

Zero Fuel Weight (ZFW)

also Zero Fuel Mass (ZFM)

  • "Zero fuel weight"

The weight without usable fuel in the tank, but including the non-usable fuel. Consists of Dry Operating Weight (DOW) plus the payload d. H. Weight of all passengers (PAXe) including luggage and hand luggage, air freight (cargo), mail.

Ramp Weight (RW)

  • Total weight of the aircraft

The Zero Fuel Weight extends the weight of the usable fuel. At this point the aircraft is fully loaded and the weight is highest.

Take Off Weight (TOW)

The weight when the brakes are released for the take-off run. (Brake Release Weight)

Manufacturer Weight Empty
+ permanently installed equipment
= Empty Weight
+ Operating materials and residual fuel
= Basic Weight
+ Catering
+ Crew and their luggage
= Dry Operating Weight
+ Payload
= Zero Fuel Weight
+ Take-Off Fuel (TOF)
+ Taxi Fuel (TF)
= Ramp Weight
- Taxi Fuel
= Take-Off Weight

Maximum taxi weight

  • Maximum total rolling weight (or Maximum Gross Taxi Weight)

Maximum weight with which the aircraft can taxi ( taxiing on the taxiway ). This weight limit is determined by the load capacity of the airframe and the entire aircraft structure.

Maximum take off weight (MTOW)

The maximum take-off weight (also off mass, take-off weight and -mass ) of the missile is the weight (mass), the missile at the moment of release may have a maximum from the ground or a support system. It is made up of the setup weight (setup mass) and the payload . This maximum weight is given by the limited structural strength of the aircraft components. During the flight, the weight of the missile is constantly reduced due to the consumption of fuel and lubricant.

Maximum Allowable Takeoff Weight (MATOW)

This value is variable and changes for each flight, e.g. B. because of insufficient runway length or density height at the take-off airport. This weight limit applies more to short-haul flights (low fuel consumption between take-off and landing), where the Planned Aircraft Landing Weight is close to the Maximum Gross Landing Weight . The take-off weight must be limited in order not to exceed the maximum total landing weight on arrival at the destination airport.

Planned Aircraft Landing Weight

  • Planned landing weight

The highest, expected weight at the destination airport (if the fuel reserves did not have to be touched - no missed approach , no holding , optimal fuel economy on the route). Planned Aircraft Landing Weight = Zero Fuel Weight + Final Reserve Fuel + Alternate Fuel + Route Reserve Fuel. The planned landing weight is the basis for all calculations: cruise altitude, range and amount of fuel (fuel load).

Maximum landing weight

  • Maximum total landing weight

The maximum weight that the aircraft can land. This maximum weight is also dictated by the limited structural strength of the aircraft components. Since the permissible landing weight is far below the permissible take-off weight, an aircraft usually cannot land again immediately after take-off (e.g. because of a bomb threat , technical problems). Since the weight is usually maxed out at take-off, the machine is too heavy for an immediate landing. Many tons of fuel have to be drained first (fuel dumping ) or, in the case of smaller aircraft, flown in holding patterns - and that takes time, sometimes hours (see web link). Therefore (and for many other reasons) there is also the departure airport an alternate airport ( Departure Alternate ), can be landed on when needed. Sometimes the runway at the airport is too short for a fully fueled aircraft to land, or the weather has fallen below the minimum for landing, or the runway is blocked by another aircraft shortly after take-off.

Maximum Allowable Landing Weight

  • Permitted, maximum landing weight

The permitted landing weight may be limited by a runway that is too short or a high density altitude at the destination airport.

Maximum Operating Weights

  • Weight limits

Weights that are specified by the flight operations: z. B. Maximum Allowable Takeoff Weight, Maximum Allowable Landing Weight.

Maximum structural weights

  • Weight limits

Weight restrictions imposed by the aircraft structure, which cannot be loaded without limits: z. B. Maximum Gross Landing Weight, Maximum Gross Takeoff Weight, Maximum Gross Taxi Weight. To comply with them, the number of passengers or the weight of the air freight may need to be reduced. If this is not possible, less fuel can be carried and a stopover for refueling (en-route fuel stop) is required.

literature

  • Joachim Scheiderer: Applied flight performance: An introduction to operational flight performance from take-off to landing . Springer Science & Business Media, Berlin / Heidelberg 2008, ISBN 978-3-540-72722-4 ( books.google.de - reading sample).
  • Niels Klußmann, Arnim Malik: Aviation Lexicon . 2nd, updated and expanded edition. Springer, Berlin / Heidelberg 2007, ISBN 978-3-540-49096-8 ( books.google.de - reading sample).
  • Carlos E. Padilla: Optimizing Jet Transport Efficiency: Performance, Operations, and Economics . McGraw Hill Professional, New York 1996, ISBN 0-07-048208-X (English).
  • Antonio Filippone: Flight Performance of Fixed and Rotary Wing Aircraft . Butterworth-Heinemann, 2006, ISBN 0-7506-6817-2 (English, books.google.de - reading sample).

Web links / sources