Operation Manual

LX90xx system Version 4.0 February 2014
Page 138 of 151
10 IGC Barograph Recalibration Procedure
The main display unit has an additional pressure sensor for altitude recording. To comply
with IGC procedures this sensor has no external pneumatic connection. To carry out the
barograph calibration procedure it is necessary to remove the instrument from the glider
and place it in a vacuum chamber. The procedure is as follows:
 Switch the instrument ON and wait some minutes (straight line on the barogram
beginning).
 Set the recording interval to 1 second (see Chapter 6.1.2).
 Place it in the chamber and carry out a short climb to about 100 m (to start the flight
recorder).
 Bring the chamber pressure to exactly 1013.2 hPa.
 Decrease the pressure by 1000 m and hold for about 30 seconds.
 Continue the procedure to 9000 m.
 Increase the pressure in 1000 m steps back to 1013.2 hPa.
 After reaching ground wait about 3 minutes and then switch the instrument off.
 Leave the instrument off for at least 5 minutes.
 Download the last flight and print the barogram.
 Restore the flight recorder settings.
The barogram will be the last flight in the logbook.