TM 55-1510-222-10
Vr
Rotation speed.
Vs
Power off stalling speed or the minimum steady flight speed at which the aircraft is controllable.
Vso
Stalling speed or the minimum steady flight speed in the landing configuration.
Vssc
The safe one-engine inoperative speed selected to provide a reasonable margin against the
occurrence of an unintentional stall when making intentional engine cuts.
Vx
Best angle of climb speed.
Vxsc
best single-engine angle of climb speed.
Vy
Best rate of climb speed.
Vysc
The best single engine rate of climb speed.
Vref
The indicated airspeed the aircraft should be at when 50 feet above the runway in landing
configuration.
Venr
One-engine-inoperative enroute climb speed.
METEOROLOGICAL TERMINOLOGY.
Altimeter Setting
Barometric pressure corrected to sea level.
°C
Degrees Celsius.
°F
Degrees Fahrenheit.
FAT
Free air temperature is the free air static temperature, obtained either from ground
meteorological sources or from inflight temperature indications adjusted for compressibility
effects.
Indicated Pressure
The number actually read from an altimeter when, the barometric scale (Kollsman
Altitude
window) has been set to 29.92 inches of mercury (1013 millibars).
ISA
International Standard Atmosphere in which:
a.
The air is a dry perfect gas:
b.
The temperature at sea level is 59 degrees Fahrenheit, 15 degrees Celsius;
c.
The pressure at sea level is 29.92 inches Hg;
d.
The temperature gradient from seal level to the altitude at which the temperature is -69.7
degrees Fahrenheit is -0.003566 Fahrenheit per foot and zero above that altitude.
Pressure Altitude
Indicated pressure altitude corrected for altimeter error.
(press alt)
SL
Sea level.
Wind
The wind velocities recorded as variables on the charts of this manual are to be understood as
the headwind or tailwind components of the actual winds at 50 feet above runway surface (tower
winds).
B-2
