background
x
loader
Troubleshooting
arrow By ATA By Message Color By Observed Faults By CAIMS By Tips

Select color for CAS message that you wish to troubleshoot

(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

This page includes :

For AOG assistance contact:

CRC Montreal (YUL)
Quick Links

10/06/19

Message Overview:

Fault Message:

L TURBINE OVERHEAT EXCEEDANCE

Fault Code:

7325325LBR

Associated CAS:

L ENGINE OVHT
(Caution)

L FADEC FAULT
(Advisory)

Reporting LRU: Left Engine Electronic Controller (EEC)
System Description: 77-20-00
Schematic Diagram: 77-20-00 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wiring Diagram: 71-50-01 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Fault Description:

The fault message is set when there is an overheat indication from the turbine overheat detection thermocouple. The thermocouple is installed in the cooling air outlet to the annulus between the High Pressure (HP2) turbine and the Low Pressure (LP1) nozzle guide vanes. This is to sense the temperature of the cooling air that comes from the turbine disc area. The Turbine Overheat Detection Thermocouple circuits are continuously monitored by the Full-Authority Digital Engine-Controller (FADEC).

This could also be an incorrect overheat indication because of a defective Turbine Overheat Detection System. The fault isolation procedure below gives data to do checks for:

  • The Turbine Overheat Detection System to make sure it is serviceable
  • The indications of an overheat condition, when a fault is found on the Turbine Overheat Detection System

Possible Causes:

  • Turbine Overheat-Detection Thermocouple
  • Left Engine Electronic Controller (EEC)

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Engine Safety Precautions AMM 71-00-00-910-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Opening of the Cowls AMM 71-10-00-010-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Closing of the Cowls AMM 71-10-00-410-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Bypass-Duct Access Panels
(451AL/461AL, 451BL/461BL, 451CL/461CL, 451DL/461DL,
451EL/461EL, 452FR/462FR, 452GR/462GR, 452HR/462HR,
452JR/462JR, 452KR/462KR)		 AMM 72-71-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Bypass-Duct Access Panels
(451AL/461AL, 451BL/461BL, 451CL/461CL, 451DL/461DL,
451EL/461EL, 452FR/462FR, 452GR/462GR, 452HR/462HR,
452JR/462JR, 452KR/462KR)		 AMM 72-71-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Deactivation of the Thrust Reverser (for Maintenance) AMM 78-30-00-040-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Activation of the Thrust Reverser (for Maintenance) AMM 78-30-00-440-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Combustion Section Fairings EMM 73-03-02-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Combustion Section Fairings EMM 73-03-02-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Engine Electronic Controller (EEC) EMM 73-21-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Engine Electronic Controller (EEC) EMM 73-21-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Oil Fire Detection Thermocouple EMM 77-22-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Oil Fire Detection Thermocouple EMM 77-22-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Turbine Overheat Detection Thermocouple EMM 77-23-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Turbine Overheat Detection Thermocouple EMM 77-23-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Troubleshooting Recommendations:

  1. Open the circuit breakers that follow:

    System Name Circuit Breaker Name Bus Name
    ENGINE L FADEC CH A BATT
    ENGINE L FADEC CH B BATT
    ENGINE L ENG IGN 1 BATT
    ENGINE L ENG IGN 2 BATT
    ENGINE L ENG FUEL HPSOV BATT
    ENGINE L ENG START A BATT
    ENGINE L ENG START B BATT
    ENGINE L T/R CTL VALVE BATT
    ENGINE L T/R LOWER LOCK BATT
    ENGINE L T/R UPPER LOCK BATT

  2. Perform a deactivation of the thrust reverser and open the cowls.
  3. Make sure that the turbine overheat detection system is serviceable, perform the troubleshooting for the turbine overheat detection thermocouple and wiring.

    1. If the system checks are not good, go to step 15.
    2. If the system checks are good, continue with next step.

  4. Perform a check of the ARINC status and maintenance discrete for the aircraft warning system for this turbine overheat condition.

    1. If the turbine overheat detection system is not serviceable, go to step 15.
    2. If the turbine overheat detection system is serviceable, continue with next step.

  5. Examine the HP turbine stage 2 blades and LP turbine stage 1 blades for indications of an overheat condition.

    1. If there is damage, repair as required and go to step 38.
    2. If there is no damage, continue with next step.

  6. Examine the pressure filter element and magnetic chip detectors for metal or carbon contamination.

    1. If there is damage or contamination, repair or replace as required and go to step 38.
    2. If there is no damage or contamination, continue with next step.

  7. Perform a detailed inspection of the front bearing chamber magnetic chip detector.

    1. If there is damage or contamination, repair or replace as required and go to step 38.
    2. If there is no damage or contamination, continue with next step.

  8. Perform a detailed inspection of the rear bearing chamber magnetic chip detector.

    1. If there is damage or contamination, repair or replace as required and go to step 38.
    2. If there is no damage or contamination, continue with next step.

  9. Perform a detailed inspection of the accessory gearbox magnetic chip detector.

    1. If there is damage or contamination, repair or replace as required and go to step 38.
    2. If there is no damage or contamination, continue with next step.

  10. Turn the LP rotor in a counterclockwise direction (when you look from the front of the engine). Make sure that the LP rotor turns freely without unusual noises.
    CAUTION:     DO NOT USE A TOOL WITH A SHARP EDGE TO TURN THE LP ROTOR. TOOLS WITH SHARP EDGES CAN CAUSE DAMAGE TO THE LP COMPRESSOR BLADES.

    1. If the LP rotor turn freely and there is no unusual noises, go to step 12.
    2. If the LP rotor does not turn freely or there are unusual noises, continue with next step.

  11. Examine the LP compressor blades and LP turbine blades for rubbing.

    1. If there is damage, repair or replace as required and go to step 38.
    2. If there is no damage, continue with next step.

  12. Turn the HP rotor in a counterclockwise direction (when you look from the front of the engine). Make sure that the HP rotor turns freely without unusual noises.

    1. If the HP rotor turn freely and there is no unusual noises, go to step 14.
    2. If the HP rotor does not turn freely or there are unusual noises, continue with next step.

  13. Examine the HP compressor and HP turbine blades for rubbing.

    1. If there is damage, repair or replace as required and go to step 38.
    2. If there is no damage, continue with next step.

  14. Perform an engine ground run.

    1. If there is indication of a turbine overheat condition, then the engine is satisfactory for operation and go to step 38.
    2. If there is no indication of a turbine overheat condition, continue with next step.

  15. On the EICAS display pages, for the engine operating limitation exceedance, record the time and temperature of the turbine overheat exceedance.
  16. Examine the stage 5 bleed valves of the HP compressor, perform a check for bleed valves that stay open when set to close.

    1. If there is damage, repair or replace as required and go to step 38.
    2. If there is no damage, continue with next step.

  17. Perform a check for signs of leakage, when the bleed valves are closed.

    1. If there is damage, repair or replace the applicable bleed valve and go to step 38.
    2. If there is no damage, continue with next step.

  18. Examine the Variable Stator Vane (VSV) system cranks, links, unison rings and actuation levers for damage.

    1. If there is damage, repair or replace as required and go to step 38.
    2. If there is no damage, continue with next step.

  19. Check for signs of incorrect operation and indications of unsatisfactory VSV system scheduling.

    1. If you find a defective VSV system, refer to the BRR representative and go to step 37.
    2. If system checks are good, continue with next step.

  20. Examine the engine and aircraft supply bleed air system for signs of leaks.
    NOTE: Look specially for signs of leaks at the bellows assemblies and at the duct interfaces.

    1. If there is leaks, repair or replace the applicable bleed air ducts and go to step 38.
    2. If there is no leaks, continue with next step.

  21. Perform a detailed inspection of the HP compressor.

    1. If there is damage, repair or replace as required and go to step 38.
    2. If there is no damage, continue with next step.

  22. Examine the rear of the HP turbine stage 2 blades for signs of lock-plate damage.

    1. If there is damage, repair or replace as required and go to step 38.
    2. If there is no damage, continue with next step.

  23. Remove the turbine overheat detection thermocouple and perform a inspection of the turbine overheat detection thermocouple for damage and indications of a turbine overheat condition.

    1. If there is damage or indications of a turbine overheat condition, repair or replace as required and go to step 38.
    2. If there is no damage or indications of a turbine overheat condition, i nstall the turbine overheat detection thermocouple and continue with next step.

  24. Examine the HP turbine stage 2 blades and LP turbine stage 1 blades for indications of an overheat condition.

    1. If there is damage, repair as required and go to step 38.
    2. If there is no damage, continue with next step.

  25. Examine the pressure filter element for metal or carbon contamination.

    1. If there is damage or contamination, repair or replace as required and go to step 38.
    2. If there is no damage or contamination, continue with next step.

  26. Perform a detailed inspection of the front bearing chamber magnetic chip detector.

    1. If there is damage or contamination, repair or replace as required and go to step 38.
    2. If there is no damage or contamination, continue with next step.

  27. Perform a detailed inspection of the rear bearing chamber magnetic chip detector.

    1. If there is damage or contamination, repair or replace as required and go to step 38.
    2. If there is no damage or contamination, continue with next step.

  28. Perform a detailed inspection of the accessory gearbox magnetic chip detector.

    1. If there is damage or contamination, repair or replace as required and go to step 38.
    2. If there is no damage or contamination, continue with next step.

  29. Turn the LP rotor in a counterclockwise direction (when you look from the front of the engine). Make sure that the LP rotor turns freely without unusual noises.
    CAUTION:     DO NOT USE A TOOL WITH A SHARP EDGE TO TURN THE LP ROTOR. TOOLS WITH SHARP EDGES CAN CAUSE DAMAGE TO THE LP COMPRESSOR BLADES.

    1. If the LP rotor turn freely and there is no unusual noises, go to step 31.
    2. If the LP rotor does not turn freely or there are unusual noises, continue with next step.

  30. Examine the LP compressor blades and LP turbine blades for rubbing.

    1. If there is damage, repair or replace as required and go to step 38.
    2. If there is no damage, continue with next step.

  31. Turn the HP rotor in a counterclockwise direction (when you look from the front of the engine). Make sure that the HP rotor turns freely without unusual noises.

    1. If the HP rotor turn freely and there is no unusual noises, go to step 33.
    2. If the HP rotor does not turn freely or there are unusual noises, continue with next step.

  32. Examine the HP compressor and HP turbine blades for rubbing.

    1. If there is damage, repair or replace as required and go to step 38.
    2. If there is no damage, continue with next step.

  33. Perform an engine ground run.

    1. If a fault is found and cannot be repaired, and/or the above checks are not satisfactory, go to step 37.
    2. If you repair any faults that are found and the above checks are satisfactory, continue with next step.

  34. The recorded time and temperature of the turbine overheat condition are within the acceptable limits (area A on graph). Use the recorded data and the Acceptable Time of Cooling Air Overheat graph.
  35. The maximum number of turbine overheat conditions (with this one) on any one engine is not more than five.
  36. This turbine overheat condition is recorded in the engine log book.
  37. Replace the power plant.
    NOTE: It is recommended that you speak to the BRR representative before you replace the power plant.
  38. Close the cowls and activate the thrust reverser.
  39. Do close out.

Registered and/or unregistered trademarks of Bombardier Inc. or its subsidiaries. © 2015 Bombardier Inc. All rights reserved.