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 the engine, which, for weight and balance purposes,
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.
Minor alteration. 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.
Static load. The load imposed on an aircraft structure due
to the weight of the aircraft and its contents.
Station. (GAMA) A location along the airplane fuselage
usually given in terms of distance from the reference datum.
Strain sensor. A device that converts a physical phenomenon
into an electrical signal. Strain sensors in a wheel axle sense
the magnitude of the force the axle deflects and create an
electrical signal that is proportional to the force that caused
the deflection
Structural station. A location in the aircraft, such as a
bulkhead, that is identifi d by a number designating its
distance in inches or percent MAC from the datum. The
datum is, therefore, identified as station zero. The stations
and arms are identical. An item located at station +50 would
have an arm of 50 inches.
Takeoff weight. The weight of an aircraft just before
beginning the takeoff roll. It is the ramp weight minus the
weight of the fuel burned during start and taxi.
Tare weight. The weight of any chocks or devices that are
used to hold an aircraft on the scales when it is weighed. The
tare weight must be subtracted from the scale reading to get
the net weight of the aircraft.
TEMAC. Trailing edge of the mean aerodynamic chord.
Type certificate data sheets (TCDS). The official
specifications issued by the FAA for an aircraft, engine, or
propeller.
Undrainable oil. The oil that does not drain from an engine
lubricating system when the aircraft is in the normal ground
attitude and the drain valve is left open. The weight of the
undrainable oil is part of the empty weight of the aircraft.
Unusable fuel. (GAMA) The fuel remaining after a test has
been completed in accordance with governmental regulations.
Usable fuel. (GAMA) The fuel available for fl ght planning.
Useful load. (GAMA) The difference between takeoff
weight, or ramp weight if applicable, and basic empty weight.
Utility category. A category of aircraft certificated under 14
CFR part 23 and CAR part 3 that permits limited acrobatic
maneuvers but restricts the weight and the CG range.
Wing chord. A straight line distance across a wing from
leading edge to trailing edge.
Zero fuel weight. The weight of an aircraft without fuel.