DOC AIRBUS | AMM A320FTEMPERATURE INDICATING SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The temperature section of the engine indicating system is related to engine Exhaust Gas Temperature (EGT), High Pressure Compressor (HPC) discharge temperature (T3) and core compartment temperature.
The temperature section of the engine indicating system is related to engine Exhaust Gas Temperature (EGT), High Pressure Compressor (HPC) discharge temperature (T3) and core compartment temperature.
A. The EGT indicating system has four thermocouple probes located around the circumference of the Turbine Exhaust Case (TEC) at semi-regular intervals.
(1) The four probes are located at the two, four, eight and ten o'clock engine positions. The EGT harness leads connect to each of the four individual EGT probes.
(2) The probes monitor the temperatures of the low pressure turbine gaspath exit temperature.
B. The EGT signal is received by the Electronic Engine Control (EEC) and is then synthesized and sent to the cockpit display.
(1) The EGT virtual gauge in the cockpit displays a virtual needle and a four-digit digital parameter (in degrees Celsius).
(2) The display also has an "amber line" and "red line" limit. The display changes to amber or red given the measured EGT and the approved limits.
2. Component Location
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Engine Indicating System (Right EGT Probes)- The EGT/T3 (WC05) harness is connected to the EGT probes on the TEC.
- The EGT probes are installed on the TEC at the 2, 4, 8 and 10 o'clock positions.
| FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 4207KS | HARNESS-EGT/T3, WC05 | 400 | 77-21-61 | ||
| 4060KS | THERMOCOUPLE-EGT, UPPER L | 400 | 73-11-00 | ||
| 4061KS | THERMOCOUPLE-EGT, UPPER R | 400 | 73-11-00 | ||
| 4062KS | THERMOCOUPLE-EGT, LOWER L | 400 | 73-11-00 | ||
| 4063KS | THERMOCOUPLE-EGT, LOWER R | 400 | 73-11-00 | ||
| 4008KS | SENSOR-TEMP, CORE AIR | 400 | 75-41-11 | ||
| 4084KS | PROBE-T3 | 400 | 73-21-25 | ||
3. System Description
A. The four signals from the probes are electrically averaged into two signals which are sent to the EEC through the EGT (T5/T3) wiring harness (WC05).
(1) The two signals from the left side are averaged into the Channel A signal.
(2) The two signals from the right side are averaged into the Channel B signal.
(3) When received by the EEC, the EEC changes the averaged EGT analog signals to digital signals.
(4) The digital signal is then transmitted to the flight deck on the ARINC 429 data bus, where it is displayed in degrees Celsius.
(5) Each probe has two studs of different dimensions and a stud/lug design with a captive nut and anti-rotation feature.
(6) The probes are Type-K thermocouples. There are two sets of K+/K- wires in the harness that transmit the signals to the cold junction reference located in the main oil temperature sensor.
(7) The T3 thermocouple probe uses the same harness to transmit its signal to the EEC.
(8) The T3 probe senses the High Pressure Compressor (HPC) gaspath exit temperature.
(9) The T-core probe senses the temperature in the core compartment between the nacelle and engine case. The signal is transmitted to the EEC by the WC08/W04 harness.
(10) When the core compartment temperature exceeds the core compartment advisory temperature limit, the appropriate signal is sent to the ECU for display in the cockpit.