Page 3 - IVAO-TR e-dergi

Airspeeds

Airspeed is the speed of an aircraft relative to the air. The working
principle of the speedometer is related to the dynamic pressure. It is the
reflection of the dynamic pressure entering through the pilot tube to the
gauge. As the dynamic pressure increases, the static pressure will

decrease.
"Total Pressure - Static Pressure = Dynamic Pressure";
Total Pressure = Static Pressure + Dynamic Pressure
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T
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d
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c
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Some errors occur while achieving speed. Therefore, with the elimination
S m e e r r c u h l c i v n p e . h r f r , i e e i i a t n
o

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h

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h
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of errors, different expressions of speed have emerged.
- Indicated airspeed (IAS or KIAS) means the speed of an aircraft as
shown on its pitot static airspeed indicator, calibrated to reflect standard
atmosphere adiabatic compressible flow at sea level, uncorrected for
airspeed system errors.
- Calibrated airspeed (CAS)
s
t
d
r
e
d
c
e
r
i
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a
is indicated airspeed corrected
i d c t d a i p e o r c e
i
s

for instrument errors, position
errors (due to incorrect pressure at the static port)
and installation errors.
-Equivalent airspeed (EAS)
is the airspeed at sea level in the
International Standard Atmosphere
s
i
at which the dynamic pressure

r
w

a t h c e d y a m i r s u e
c
h

h
t
e
n
p
is the same as the dynamic pressure
at the true airspeed (TAS)
and altitude at which the
aircraft is flying.
-True airspeed (TAS or KTAS) is the speed
o e a i r f l t e t e a m o p h r . h u i p e n e d i g
t
a
r
e
r
n
d
a
e
s
a
d
h
of the aircraft relative to the atmosphere. The true airspeed and heading
a
t

h
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h
v
a
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c
o

r
t
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T

f
t
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s
of an aircraft constitute its velocity relative to the atmosphere.
-Ground speed (GS) is the speed of the aircraft relative to the ground.
This speed is the combination of the true airspeed vector of the aircraft
and the speed vector of wind at aircraft altitude.