Symphony SA-160 - Page 24

AIRCRAFT
SA 160
AIRCRAFTA I R C R A F T
Symphony
1-10
SECTION 1
GENERAL
(b) Meteorological Terminology
ISA
OAT
MSN
Indicated Pressure Altitude
Pressure Altitude
Station Pressure
International Standard Atmosphere
Outside Air Temperature
inwhich
(1) The air is a dryperfectgas;
(2) The temperature at sea level is 15° Celsius (59° Fahrenheit);
(3) The pressure at sea level is 29.92 inches h g.(1013.2 mb);
(4) The temperature gradient from sea level to the altitude at which
thetemperatureis-56.5°C(-69.7°F)is-0.00198°C
(-0.003564°F)perfootandzeroabovethataltitude.
is the free air static temperature, obtained
either from inflight temperature indications or ground
meteorological sources, adjusted for instrument error and
compressibilityeffects.
Mean Sea Level
The number actually read from an altimeter when the barometric
subscalehasbeensetto29.92inchesofmercury(1013.2mb).
Altitudemeasured from standard sea level pressure (29.92in. hg.) by
a pressure or barometric altimeter. It is the indicated pressure
altitude corrected for position and instrument error. In this
Handbook,altimeterinstrumenterrors are assumed to be zero.
Actualair pressure at field elevation.
Feb 25, 2005