190-01279-01
GTS 8XX Part 23 AML STC Maintenance Manual
Rev. 2
Page 5-5
Notes:
[1] If self-test is controlled through a compatible display, refer to display documentation for self-test procedures.
1090 MHz
Receive frequency synthesizer is not
locked.
1. Cycle GTS 8XX power and run self-test. [1]
2. Analyze the assert log. See Section 5.2.
Receiver Cal
GTS 8XX receiver is out of calibration.
1. Check antenna installation and all cable connections and run self-test. Ensure that self-test
occurs in an area free of buildings and large structures that might reflect signals. See
Section 7.3.1.3. Receiver self-calibration and test is performed prior to transmitter calibration
and test. In the event that a receiver calibration fault occurs, transmitter self-calibration and
testing will not be performed.
2. Analyze the assert log. See Section 5.2.
Transmitter Cal
GTS 8XX transmitter is out of calibration.
1. Check antenna installation and all cable connections and run self-test. Ensure that self-test
occurs in an area free of buildings and large structures that might reflect signals. See
Section 7.3.1.3. Receiver self-calibration and test is performed prior to transmitter calibration
and test. In the event that a receiver calibration fault occurs, transmitter self-calibration and
testing will not be performed.
2. Analyze the assert log. See Section 5.2.
Pressure Altitude
Ownship barometric altitude calculation
is invalid or has timed out.
Check wiring to the barometric altitude source and ensure that the source is operating. The fault will
clear as soon as valid barometric altitude data is received.
Temperature
Main board or RF receiver temperature is
higher than 100° Celsius or lower than
-60° Celsius. Fault will persist until
internal temperature returns to
acceptable range.
1. Ensure that the GTS 8XX has adequate ventilation and the fan is not obstructed.
2. Analyze the assert log. See Section 5.2.
TCAS Equipage
GTS 8XX is not receiving TCAS
Equipage data.
1. Ensure that transponder is operating properly.
2. Check GTS 8XX wiring to the transponder. This fault will clear as soon as valid TCAS
source data is received.
Radio Altitude
GTS 8XX is not receiving radar altimeter
data.
1. Ensure that radar altimeter is operating properly.
2. Check GTS 8XX wiring to radar altimeter. This fault will clear as soon as valid radio altitude
data is received.
Fault
Description
Corrective Action
