TQ Aviation
KTX2-F.0100
EASA.AP445
MAN
KTX2-F.A-MAN.0001.docx
Page 50 of 74
© TQ-Systems GmbH. All information contained in this documents have to be treated strictly confidential. The transfer of presentations and know-how to third parties
requires the prior written consent of TQ-Systems GmbH.
3.4.5.1 Altitude Offset Calibration
The Altitude Offset Calibration allows you to adjust the built-in altitude encoder to ensure that the flight
level transmitted by the transponder complies with all relevant standards.
This process is normally carried out every 24 months, as part of the altimeter checks on the aircraft. The
maximum allowed difference between the primary altimeter and the altitude encoder is 125 feet
according to ETSO C88a.
The altitude encoder in the transponder is extremely accurate, has an excellent long-term stability and is
accurately calibrated during manufacture. But it is possible that a combination of allowed accuracy
deviations in the altitude encoder and the primary altimeter may show an altitude difference exceeding
125 feet. In that case it is recommend to perform an altitude offset calibration.
3.4.5.1.1 Calibration Equipment
To perform the altitude offset calibration the transponder needs to be powered up. Additionally a pitot
static test set is needed together with the appropriate adapters to connect to the static port on the
aircraft. The pitot static test set should be able to drive the altitude from sea level to above the service
ceiling of the aircraft.
Note:
For the calibration procedure no transponder test set is required. During the calibration procedure all
necessary information is displayed. Nevertheless a transponder test set can be used to verify the
transmissions of the transponder.
3.4.5.1.2 Calibration Procedure
Figure 39: Altitude Offset Calibration Menu
To perform the altitude offset calibration perform the following procedure:
1. Select “Altitude” and press the rotary knob. The first digit of the altitude set point turns yellow.
2. Turn the rotary knob to change the value.
3. Press the rotary knob again to save the selected digit. The next digit turns yellow.
4. Repeat steps 2 and 3 until all digits are set to desired altitude set point.
Note: It is recommended to use 18000 ft as altitude set point.
5. On the pitot static test set drive the altitude to the set point value as entered before and wait until
the pressure has stabilized.
6. Select “Start” and press the rotary knob. The calibration procedures is started. During the “Delta”
value shows three dashes (“---“).
