TM 55-1510-219-10
Route Segment
A part of a route. Each end of that part is identified by:
a. A geographic location; or
b. A point at which a definite radio fix can be established.
Service Ceiling
The altitude at which the minimum rate of climb of 100 feet per minute can be at-
tained for existing aircraft weight.
Takeoff Weight
The weight of the aircraft at liftoff from the runway.
WEIGHT AND BALANCE TERMINOLOGY.
Arm
The distance from the center of gravity of an object to a line about which moments
are to be computed.
Approved Loading
Those combinations of aircraft weight and center of gravity which define the limits
Envelope
beyond which loading is not approved.
Basic Empty Weight
The aircraft weight with unusable fuel, full oil, and full operating fluids.
Center-of-Gravity
A point at which the weight of an object may be considered concentrated for weight
and balance purposes.
CG Limits
CG limits are the extremes of movement which the CG can have without making
the aircraft unsafe to fly. The CG of the loaded aircraft must be within these limits
at takeoff, in the air, and on landing.
Datum
A vertical plane perpendicular to the aircraft longitudinal axis from which fore and
aft (usually aft) measurements are made for weight and balance purposes.
Engine Oil
That portion of the engine oil which can be drained from the engine.
Empty Weight
The aircraft weight with fixed ballast, unusable fuel, engine oil, engine coolant, hy-
draulic fluid, and in other respects as required by applicable regulatory standards.
Landing Weight
The weight of the aircraft at landing touchdown.
Maximum Weight
The largest weight allowed by design, structural, performance or other limitations.
Moment
A measure of the rotational tendency of a weight, about a specified line, mathemati-
cally equal to the product of the weight and the arm.
Standard
Weights corresponding to the aircraft as offered with seating and interior, avionics,
accessories, fixed ballast and other equipment specified by the manufacturer as
composing a standard aircraft.
Station
The longitudinal distance from some point to the zero datum or zero fuselage sta-
tion.
Takeoff Weight
The weight of the aircraft at liftoff.
Unusable Fuel
The fuel remaining after consumption of usable fuel.
Usable Fuel
That portion of the total fuel which is available for consumption as determined in
accordance with applicable regulatory standards.
Useful Load
The difference between the aircraft ramp weight and basic empty weight.
B-4
