14
scale at every altitude.
Standard, commercially available, Pitot tubes are used for speed-senders. The speed
indicator is calibrated by
BRÄUNIGER
according to the corresponding dynamic air
pressure.
4.1.1 Calibration of Air Speed (CAS)
The pilot can individually calibrate the speed indicator in SET-Mode 15 by adjusting the
SPEED GAIN factor. This way measurement errors, caused e.g. by a not optimal
position of the Pitot tube, can be individually corrected. After calibration, CAS
(Calibrated Air Speed) is indicated. The default value is >100<. If you adjust the
SPEED GAIN e.g. to <110> the speed indication will show a approx. 10% higher CAS.
The easiest way to calibrate the air speed indicator is to use a GPS. On a day with no
wind the Ground Speed is compared to the Indicated Air Speed. You should fly your
entire speed range, i.e. landing speed, medium speed, cruise speed and close to the
Vne. The differences in GS to IAS will probably vary through the speed range. It is
optimal to calibrate close to landing speed. It is also recommended to fly different
courses (e.g. 360°, 270°, 180° und 90°) to eliminate possible wind influences.
Additionally the speed zero point can be calibrated. This is done in SET-Mode 16
(SPEED ZERO).Press two times the “Enter” key.
.
WARNING!
The possibility to calibrate the Air Speed Indicator allows for a very accurate
calibration of the Calibrated Air Speed. But if the calibration is
done
incorrectly,
the CAS indication can show
inaccurate speeds
which can
lead
to serious accidents (landing!) Therefore Aircraft manufacturers can
block the settings for Speed calibration. Stall and Vne for the user.
It is also highly recommended to
calibrate
the speed zero point every
2-3 months
to preserve accuracy.
4.1.2 Speed Indication “Stretching Schemes” / Units Air Speed
The
ALPHA
ALPHA
ALPHA
ALPHA
MFD
is available in 6 different versions:
Version
Speed-Units
Speed-Range
VSI Units
Version A
Km/h
40 – 220 km/h
m/s
Version B
Km/h
60-340 km/h
m/s
Version C
Knots or mph
24 –130 kts
ft/min
Version D
Knots or mph
32 – 190 kts
ft/min
Knots-versions can be converted to mph-versions. This must be done at the factory.
Km/h-versions can also be converted to kts or mph versions. Again this must be done
at
BRÄUNIGER
.
