Maximum taxi weight. The maximum weight approved for ground maneuvers. This is the same as maximum ramp weight. 

Maximum weight. The maximum authorized weight of the aircraft and all of its equipment as specified in the Type Certificate Data Sheets (TCDS) for the aircraft 

Maximum zero fuel weight. The maximum authorized weight of an aircraft without fuel. This is the total weight for a particular flight minus the fuel. It includes the aircraft and everything that is carried on the flight except the weight of the fuel. 

Mean aerodynamic chord (MAC). The average distance from the leading edge to the trailing edge of the wing. 

METO horsepower (maximum except takeoff HP).  The maximum power allowed to be produced continuously by an engine. Takeoff power is usually limited to a given amount of time, such as 1 minute or 5 minutes. 

Minimum fuel.  The amount of fuel necessary for one-half hour of operation at the rated maximum-continuous power setting of theengine, which, for weightand balancepurposes, is 1 ⁄12  gallon per maximum-except-takeoff (METO) horse- power. It is the maximum amount of fuel that could be used in weight and balance computations when low fuel might adversely affect the most critical balance conditions. To determine the weight of the minimum fuel in pounds, divide the METO horsepower by two. 

M inoralteration.  An alteration other than a major alteration. This includes alterations that are listed in the aircraft, aircraft engine, or propeller specifications 

Moment.  A force that causes or tends to cause an object to rotate. It is indicated by the product of the weight of an item multiplied by its arm. 

Moment. (GAMA) The product of the weight of an item multiplied by its arm. (Moment divided by a constant is used to simplify balance calculations by reducing the number of digits; see reduction factor.) 

Moment index.  The moment (weight times arm) divided by a reduction factor. 

Moment limits versus weight envelope.  An enclosed area on a graph of three parameters. The diagonal line, representing the moment/100, crosses the horizontal line, representing the weight at the vertical line, representing the CG location in inches aft of the datum. If the lines cross inside the envelope, the aircraft is loaded within its weight and CG limits. 

Net weight. The weight of the aircraft minus the weight of chocks or other devices used to hold the aircraft on the scales. 

Normal category.  A category of aircraft certificat d under 14 CFR part 23 and CAR part 3 that allows the maximum weight and CG range while restricting the maneuvers that are permitted. 

PAX.  The abbreviation of passengers. 

Payload. (GAMA) The weight of occupants, cargo, and baggage. 

Percent MAC. The distance in inches of the CG from LEMAC divided by the MAC. It is a good standard for CG location in airplanes because it permits a standard weight and balance program for different types of airplanes. 

Pilot’s operating handbook (POH). An FAA-approved document published by the airframe manufacturer that lists the operating conditions for a particular model of aircraft and its engine(s). 

Potable water. The water carried in an aircraft for the purpose of drinking. 

Ramp weight.  The zero fuel weight plus all of the usable fuel on board. 

Reference datum. (GAMA) An imaginary vertical plane from which all horizontal distances are measured for balance purposes. 

Reduction factor. A number, usually 100 or 1,000, by which a moment is divided to produce a smaller number that is less likely to cause mathematical errors when computing the center of gravity. 

Residual fuel.  The fuel that remains trapped in the system after draining the fuel from the aircraft with the aircraft in level flight attitude. The weight of this residual fuel is counted as part of the empty weight of the aircraft. 

Service ceiling. The highest altitude at which an aircraft can maintain a steady rate of climb of 100 feet per minute. 

Small aircraft (14 CFR part 1).  An aircraft weighing 12,500 pounds or less maximum certificated takeoff weight 

Standard empty weight.  (GAMA) The weight of a standard airplane including unusable fuel, full operating fluids, and full oil. 

