TM 55-1510-221-10
APPENDIX B
ABBREVIATIONS AND TERMS
For the purpose of this manual, the following abbreviations and terms apply. See appropriate technical
manuals for additional terms and abbreviations.
Airspeed Terminology.
CAS
FT/MIN
GS
IAS
Calibrated airspeed is indicated airspeed corrected for position and
instrument error.
Feet per minute.
Ground speed, though not an airspeed, is directly calculable from true
airspeed if the true wind speed and direction are known.
Indicated airspeed is the speed as shown on the airspeed indicator and
assumes no error.
KT
TAS
V a
V f
V fe
Knots.
True airspeed is calibrated airspeed corrected for temperature, pres-
sure, and compressability effects.
Maneuvering speed is the maximum speed at which application of full
available aerodynamic control will not overstress the aircraft.
Design flap speed is the highest speed permissible at which wing flaps
may be actuated.
Maximum flap extended speed is the highest speed permissible with
wing flaps in a prescribed extended position.
V le
V 1o
V lof
Vmea
Vmo
Vne
vr
vs
Maximum landing gear extended speed is the maximum speed at
which an aircraft can be safely flown with the landing gear extended.
Maximum landing gear operating speed is the maximum speed at
which the landing gear can be safely extended or retracted.
Lift off speed (takeoff airspeed).
The minimum flight speed at which the aircraft is directionally con-
trollable as determined in accordance with Federal Aviation Regula-
tions. Aircraft Certification conditions include one engine becoming
inoperative and windmilling; a 5° bank towards the operative engine;
takeoff power on operative engine; landing gear up; flaps up; and most
rearward CG. This speed has been demonstrated to provide satisfac-
tory control above power off stall speed (which varies with weight,
configuration, and flight attitude).
Maximum operating limit speed.
Never exceed speed.
Rotation speed.
V s o
Vsse
Power off stalling speed or the minimum steady flight speed at which
the aircraft is controllable.
Stalling speed or the minimum steady flight speed in the landing con-
figuration.
The safe one-engine inoperative speed selected to provide a reasonable
margin against the occurence of an unintentional stall when making
intentional engine cuts.
B-1
