Weight Definitions and Limit Weight_Definitions_and_Limitationsations

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Weight Definitions and Limitations

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Operating Weight Definitions

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Manufacturer’s Empty Weight:Weight of the structure, powerplant, furnishings, systems and other items of equipment that are an integral part of a particular aircraft configuration. It is essentially a “dry” weight, including only those fluids contained in closed systems.Includes: - airframe, systems

- closed system fluids- seats, seat belts- seller-furnished emergency equipment- fire extinguishers

Does not include: - galley structure, ovens, inserts, etc.- escape slides- life rafts, life vests- portable oxygen bottles- fluids like engine oil, trapped fuel, potable water

Operating Weight Terms and Definitions Operating Weight Terms and Definitions

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Standard Items:Equipment and system fluids which are not considered an integral part of a particular aircraft configuration, are not included in the MEW, but which do not normally vary for aircraft of the same type. Standard items may include, but are not limited to:

- unusable fuel, oil, and engine injection fluids- unusable drinking and washing water- first aid kits, flashlights, megaphone, etc- emergency oxygen equipment- galley/bar structure, inserts, ovens, etc.- electronic equipment required by the operator


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Basic Empty Weight:Manufacturer’s empty weight plus Standard Items.(From an equipment standpoint, the airplane is ready for operation.)


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Operational Items:Personnel, equipment and supplies necessary for a particular operation but not included in the Basic Empty Weight. These items may vary for a particular aircraft and may include, but are not limited to:

- flight and cabin crew plus their baggage- manuals and navigation equipment- removable service equipment:

cabin (blankets, pillows, papers, etc.)galley (food, beverages, etc.)

- usable drinking and washing water- toilet fluid and chemical- life rafts, life vests, emergency transmitters- cargo containers, pallets, and/orcargo tiedown equipment if used.


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Operational Empty Weight:Basic Empty Weight plus Operational Items. This is essentially the takeoff weight, except for fuel and payload.

(Some airlines will call this “Dry Operating Weight,” or, “Basic Weight”)


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MEW

Standard Items

OperationalItems

Wei

ght

Basic Empty Weight

Operational Empty Weight(Dry Operating Weight)

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Weight Limitations

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Certified Weight Limitations Certified Weight Limitations

The maximum allowable weights as listed in the AFM, and Weight and Balance Manual, may be limited by:

Structural Limits:Based on airplane structural capabilityDefines the “envelope” for the c.g. chart – both maximum weight and c.g. limits

Certified Weight Limits:Maximum weights chosen by the airlineSome airlines refer to these as the “purchased weights”(Certified weight limits are often below the structural limits)

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Maximum Taxi Weight (MTW):Maximum weight allowed for movement of the airplane on the ground (taxiing or towing).

Maximum Takeoff Weight (MTOW):Maximum weight allowed at the start of the takeoff run. (design for 6 fps rate of sink with no structural damage)

Maximum Landing Weight (MLW):The maximum weight allowed for landing of the airplane. (design for 10 fps rate of sink with no structural damage)

Maximum Zero Fuel Weight (MZFW):Maximum weight allowed before usable fuel must be loaded in defined sections of the aircraft.

Certified Weight Limitations Certified Weight Limitations

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Additional Weight Limitations Additional Weight Limitations

Maximum In-flight Weight (MFW):The maximum weight for flight with landing flaps deployed. (747 classic, 737 classic, 727)

Maximum Fuel Transfer Weight (MFTW):The maximum weight for initiating fuel transfer from reserve tanks to the main tanks. (747)

Minimum Inflight Weight (MFW):The minimum allowed weight during flight. Establishes the load factor for airplane fixed equipment.

Note that the maximum structural weight limits may be less as limited by center of gravity, fuel density, and fuel loading limits.

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Operational Weight LimitationsOperational Weight LimitationsThe maximum allowable Operational Takeoff Weightmay be limited to a weight which is lower than the Certified Maximum Weight by the most restrictive of the following requirements:

• Airplane performance requirements for a given altitude and temperature:

- Takeoff field length available- Tire speed and brake energy limits- Minimum climb requirements- Obstacle clearance requirements

• Noise requirements• Tire pressure limits• Runway loading requirements• Center of gravity limitations

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The Operational Landing Weight may be limited to a weight lower than the Certified Maximum Landing Weight by the most restrictive of the following requirements:

• Airplane performance requirements for a given altitude and temperature:

- Landing field length requirements- Approach and landing climb requirements

• Noise requirements

Operational Weight LimitationsOperational Weight Limitations

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Components of Takeoff Weight Components of Takeoff Weight

OEW

PASS & BAGS

RESERVE FUEL

Wei

ght CARGO

TRIPFUEL

TAXI OUT FUEL

TOTALFUEL

LOADED

Zero Fuel Wt (≤ MZFW)

Takeoff Wt (≤ MTOW)

Landing Wt (≤ MLW)

TOTALPAYLOAD

Taxi Wt (≤ MTW)

TOW = OEW + (PASS & BAGGAGE) + CARGO + TOTAL FUEL LOADED – TAXI OUT FUEL

B-16

60

50

40

30

20

10

00 1 2 3 4 5

Payload~ 1,000 lb(1,000 kg)

Range ~ 1,000 nmi (1,000 km)

Fuel capacity, U.S. gal (L)

6,875 (26,020)

(25)

(20)

(15)

(10)

(5)

(0)

(0) (1) (2) (3) (4) (5) (6) (7) (8) (9)

MTOW ~ lb (kg)

Weight Components are Reflected in the Payload Range of an AirplaneWeight Components are Reflected in the Payload Range of an Airplane

737-800 Payload-Range

Typical Mission Rules and ReservesStill Air, Standard DayTypical OEW

162 passengers

155,000 (70,530)

174,200 (79,010)737-800

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End ofWeight Definitions and Limitations

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Weight Definitions and Limit Weight_Definitions_and_Limitationsations