In aviation, manufacturer's empty weight (MEW) (also known as manufacturer's weight empty (MWE)) is the weight of the aircraft "as built" and includes the weight of the structure, power plant, furnishings, installations, systems, and other equipment that are considered an integral part of an aircraft before additional operator items are added for operation.
''Basic aircraft empty weight'' is essentially the same and excludes any baggage, passengers, or
usable fuel In aviation, usable fuel is the fuel on board an aircraft that can actually be used by its engines. The opposite of usable fuel is unusable fuel.Websters dictionary oUnusable fuel visited 19 March, 2012
The unusable fuel figure is calculated for a ...
. Some manufacturers define this empty weight as including optional equipment, i.e. GPS units, cargo baskets, or spotlights.
Specification MEW
This is the MEW quoted in the manufacturer's standard specification documents and is the aircraft standard basic dry weight upon which all other standard specifications and aircraft performance are based by the manufacturer.
The Specification MEW includes the weight of:
[Torenbeek, Egbert. ''Synthesis of Subsonic Airplane Design''. Delft University Press. .]
*
Airframe
The mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and excludes the propulsion system.
Airframe design is a field of aerospa ...
structure – primary and secondary structures (
fuselage
The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
,
wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
, tail, control surfaces,
nacelle
A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...
s,
landing gear
Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...
).
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Powerplant
Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived from ...
.
*
Auxiliary power unit
An auxiliary power unit (APU) is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft and naval ships as well as some large land vehicles. Aircraft APUs generally produce 115&n ...
(APU).
* Systems (instruments, navigation, hydraulics, pneumatics, fuel systems (''but not fuel itself''), electrical system, electronics, fixed furnishings (''but not operator specific''), air conditioning, anti-ice system, etc.).
* Fixed equipment and services considered an integral part of the aircraft.
* Fixed ballast (if present).
* Closed system fluids (such as
hydraulic fluid
A hydraulic fluid or hydraulic liquid is the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water. Examples of equipment that might use hydraulic fluids are excavators and backhoe ...
s).
For small aircraft, the MEW may include unusable fuel and oil.
The Specification MEW excludes the weight of:
* All fuel (both usable and unusable).
* Potable water, anti-ice, and chemicals in toilets.
* Engine oil and APU oil.
* All specification items, selections, and installations which are non-basic (i.e. optional selections).
* Customer specific selections, installations, and options.
* Operator/operating items.
* Removable equipment and services.
* Payload.
For small aircraft, the specification MEW is known as the ''standard empty weight'' (or ''standard weight empty'').
See also
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Aircraft gross weight
The aircraft gross weight (also known as the all-up weight and abbreviated AUW) is the total aircraft weight at ''any moment'' during the flight or ground operation.
An aircraft's gross weight will decrease during a flight due to fuel and oil co ...
*
Operating empty weight
Empty weight (EW) is the sum of the ‘as built’ manufacturer's empty weight (MEW), plus any standard items (SI) plus any operator items (OI), EW = MEW + SI + OI. The EW is calculated for each aircraft series and each unique configuration of an a ...
References
External links
Aircraft weight and balance
Aircraft weight measurements
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