Manufacturer’s Empty Weight (MEW)
It is the weight of structure, power plant, furnishings, systems and other items of equipment that are considered an integral part of the aircraft. It is dry weight including only those fluids which are contained in closed systems(e.g. hydraulic fluid).
Operational Empty Weight (OEW)
It is the sum of manufacturer’s empty weight and operator’s items. Operator’s items include flight and cabin crew and their baggage, unusable fuel, engine oil, emergency equipment, toilet chemicals and fluids, galley structure, catering equipment, seats, documents, etc.
Dry Operating Weight (DOW)
It is the total weight of aircraft ready for a specific type of operation excluding all usable fuel and traffic load. It is sum of operational empty weight plus items specific to flight type(catering, pantry equipment, newspapers etc).
Difference between Operational Empty Weight and Dry Operating Weight (OEW and DOW)
Till the calculation of operational empty weight, type of operation is not defined. Type of operation can be cargo flight, domestic flight, international flight, relief flight etc. Now depending on this need Dry Operating Weight is calculated.
Zero Fuel Weight (ZFW)
It is the sum of dry operating weight and total payload.
Landing Weight (LW)
It is the weight at landing at the destination airport. It is equal to zero fuel weight plus the fuel reserves
Maximum Structural Landing Weight (MLW)
MLW is determined in accordance with structure criteria during landing impact with vertical speed equal to -600 fpm (Airbus A320)
Takeoff Weight (TOW)
This is the weight of takeoff at departure airport. It is the sum of landing weight at destination and trip fuel.
Maximum Structural Takeoff Weight (MTOW)
MTOW is determined in accordance with in flight structural resistance criteria, resistance of landing gear and structure criteria during a landing impact with vertical speed equal to -360 fpm (Airbus A320)
Maximum Structural Zero Fuel Weight (MZFW)
This is defined to cater for wing bending moment. Bending moment is maximum at wing root an when fuel in wings i minimum. AS the fuel decreases during flight, bending moment increases. To cater for this it is necessary to limit the weight when there is no fuel in the tanks. This limit value is called as Maximum Zero Fuel Weight (MZFW).
Minimum Structural Takeoff Weight – this term is not usually read in aviation manuals but it does exists.
This is the minimum weight selected by manufacturer at which compliance with each structural loading condition and each applicable flight requirement of JAR/FAR Part 25 is shown. Gusts and Turbulence loads are among the criteria considered to determine that minimum structural weight.