DOC AIRBUS | AMM A320FTEMPERATURE - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The temperature sub-system includes two systems:
** ON A/C NOT FOR ALL The temperature sub-system includes two systems:
- Exhaust Gas Temperature (EGT) system (Ref. AMM D/O 77-21-00-00)
- Core Compartment Temperature (CCT) system (Ref. AMM D/O 77-22-00-00).
2. System Description
A. EGT System
The function of the eight EGT sensors is to measure the EGT at the inlet of the Low Pressure Turbine (LPT) stage of the engine.
The EGT sensors (also named T48 sensors) are used to determine the EGT margin and to survey the engine start, relight and operating T48 temperature. The eight EGT sensors are identical and fully interchangeable.
The EGT sensors are located on the engine Turbine Center Frame (TCF) on the core.
The EGT sensor is a Line Replaceable Unit (LRU).
The eight probes are immerged in the engine exhaust gas stream in front of the LPT nozzle stage 1.
The EGT sensors are flange mounted and bolted into the outer engine casing at plane 48. Each EGT sensor has a single sensing element. The sensing element is a thermocouple probe.
The thermocouple probe for temperature measurement is a junction of specific two alloys (called Kp and Kn) which have a predictable and repeatable relationship between temperature and voltage generated.
EGT sensor consists of a spring which pushes the sensor against the low-pressure stage one nozzle ensuring proper thermocouple probe immersion in the engine gas stream and the air sealing with the internal engine casing.
Two electrical terminal connections are located on the top of the sensor housing to attach the EGT harness. One for Kp, one for Kn.
The measurements given by the eight EGT sensors are compared to each other and are averaged. This weighted average is named EGT value. This is the value reported to the cockpit.
The weighting of the different sensor measurements is obtained by comparing the measurement given by each sensor with the EGT value at the previous time. The more the measurement of one sensor is far from the previous EGT value, the less it is used to calculate the new average.
In case of failure of one of the sensor, its weighting is set to zero and thus its measurement is not used in the calculation anymore.
Only one measurement is needed to calculate an EGT value (meaning that only one sensor functioning is needed).
The two EGT harnesses (T48-Left and T48-Right) function is to connect the eight EGT sensors to the two engine harnesses channel A and channel B.
Each harness has the main function to carry four independent EGT signals from four EGT sensors to the EEC (no internal averaging).
The harness, T48-Left connects the EGT sensors 1, 8, 7 and 6 to the EEC channel A.
The harness, T48-Right connects the EGT sensors 2, 3, 4 and 5 to the EEC channel B.
The two EGT harnesses are routed and mounted on the core area engine external case.
The function of the eight EGT sensors is to measure the EGT at the inlet of the Low Pressure Turbine (LPT) stage of the engine.
TemperatureThe EGT sensors (also named T48 sensors) are used to determine the EGT margin and to survey the engine start, relight and operating T48 temperature. The eight EGT sensors are identical and fully interchangeable.
The EGT sensors are located on the engine Turbine Center Frame (TCF) on the core.
The EGT sensor is a Line Replaceable Unit (LRU).
The eight probes are immerged in the engine exhaust gas stream in front of the LPT nozzle stage 1.
The EGT sensors are flange mounted and bolted into the outer engine casing at plane 48. Each EGT sensor has a single sensing element. The sensing element is a thermocouple probe.
The thermocouple probe for temperature measurement is a junction of specific two alloys (called Kp and Kn) which have a predictable and repeatable relationship between temperature and voltage generated.
EGT sensor consists of a spring which pushes the sensor against the low-pressure stage one nozzle ensuring proper thermocouple probe immersion in the engine gas stream and the air sealing with the internal engine casing.
Two electrical terminal connections are located on the top of the sensor housing to attach the EGT harness. One for Kp, one for Kn.
The measurements given by the eight EGT sensors are compared to each other and are averaged. This weighted average is named EGT value. This is the value reported to the cockpit.
The weighting of the different sensor measurements is obtained by comparing the measurement given by each sensor with the EGT value at the previous time. The more the measurement of one sensor is far from the previous EGT value, the less it is used to calculate the new average.
In case of failure of one of the sensor, its weighting is set to zero and thus its measurement is not used in the calculation anymore.
Only one measurement is needed to calculate an EGT value (meaning that only one sensor functioning is needed).
The two EGT harnesses (T48-Left and T48-Right) function is to connect the eight EGT sensors to the two engine harnesses channel A and channel B.
Each harness has the main function to carry four independent EGT signals from four EGT sensors to the EEC (no internal averaging).
The harness, T48-Left connects the EGT sensors 1, 8, 7 and 6 to the EEC channel A.
The harness, T48-Right connects the EGT sensors 2, 3, 4 and 5 to the EEC channel B.
The two EGT harnesses are routed and mounted on the core area engine external case.
B. CCT System
The main fucntion of the LEAP-1A core temperature sensor is to monitor the temperature of the air under the T/R cowl.
Its sensing end is positioned near bleed ducting to indicate any leaks that occur at their main interfaces. The sensing element is a type K thermocouple. There is one thermocouple signal, which is routed to EEC channel A only. This sensor signal is processed by the FADEC. The temperature value is monitored via ECAM and will trigger a fault message only in the event of an out-of-range value. The cockpit uses this data to detect hot air leaks (e.g. environmental control system duct) in the core compartment which drives a maintenance action. The sensor has no engine control function.
The LEAP-1A core temperature sensor is located on the engine as shown mounted on a core-mounted bracket.
The main fucntion of the LEAP-1A core temperature sensor is to monitor the temperature of the air under the T/R cowl.
Its sensing end is positioned near bleed ducting to indicate any leaks that occur at their main interfaces. The sensing element is a type K thermocouple. There is one thermocouple signal, which is routed to EEC channel A only. This sensor signal is processed by the FADEC. The temperature value is monitored via ECAM and will trigger a fault message only in the event of an out-of-range value. The cockpit uses this data to detect hot air leaks (e.g. environmental control system duct) in the core compartment which drives a maintenance action. The sensor has no engine control function.
The LEAP-1A core temperature sensor is located on the engine as shown mounted on a core-mounted bracket.