12/29/25
Message Overview:
Message Name:
TR ICU 9
Message Code:
B3-304270
| Reporting LRU: | Right Engine Thrust Reverser Isolation Control-Unit (R ENG TR ICU) |
| Associated CAS: | R ENGINE FAULT (Advisory) |
| System Description: | 78-32-00 - Thrust Reverser Actuating System |
| Schematic Diagram: | SSM 78-30-00-101 - Thrust Reverser |
| Wiring Diagram: | WM 78-32-09-1_001 - Sheet 1 - Thrust-Reverser Isolation Control-Unit (ICU) RHS - ALL |
Message Description:
Right Engine Thrust Reverser Isolation Control-Unit (ICU) fault 9.
[MCID 1447]
TR ICU 9.A fault in the TR ICU Pressure Indication Switch, the TR ICU Hydraulic Valve, the Aircraft Wiring Harness between the TR ICU and both the Electronic Control Unit (ECU) Channel A and ECU Channel B was sensed.
Possible Causes:
- Aircraft Wiring Harness
- Wiring Harness (W1)
- Right Full Authority Digital Engine Control (FADEC) Channel A (A40)/Electronic Control Unit (ECU)
- Right Full Authority Digital Engine Control (FADEC) Channel B (A42)/Electronic Control Unit (ECU)
- Aircraft Wiring Harness
- Right Thrust Reverser Isolation Control Unit (ICU) (A116)
Troubleshooting Tips:
Advisory Wire/Service Bulletin:
- AW300-78-0425 - Isolation Control Unit (ICU) Replacement
Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None
Flight Operation Notifications Manual (FONM): None
NOTES:
- MCID 1447 fault present, troubleshoot using the following steps for aircraft and engine fault isolation with reference to the Light Engine Maintenance Manual TASK 72-00-00-810-273
Quick Links:
| Removal of the Engine Electronic Control Unit (ECU) | AMM 76-10-05-000-801 |
| Installation of the Engine Electronic Control Unit (ECU) | AMM 76-10-05-400-801 |
| Deactivation of the Thrust Reverser (For Maintenance) | AMM 78-30-00-040-801 |
| Activation of the Thrust Reverser (For Maintenance) | AMM 78-30-00-440-801 |
| Operational Test of the Thrust Reverse | AMM 78-30-00-710-801 |
| General Visual Inspection of the Thrust Reverser | AMM 78-30-00-210-802 |
| Removal of the Thrust-Reverser Isolation Control-Unit (ICU) | AMM 78-32-07-000-801 |
| Installation of the Thrust-Reverser Isolation Control-Unit (ICU) | AMM 78-32-07-400-801 |
| General Visual Inspection of the Thrust-Reverser Wiring Harness | AMM 78-33-00-210-801 |
| Removal of the Thrust-Reverser Harness (Multiplexer) | AMM 78-33-06-000-804 |
| Installation of the Thrust-Reverser Harness (Multiplexer) | AMM 78-33-06-400-804 |
| Safety Precautions - Maintenance Practices - ALL | SPM 20-00-01-02 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
| Electrical Connectors - Maintenance Practice - ALL | SPM 20-20-00-02 |
Troubleshooting Recommendations:
- MCID 1447 fault present, troubleshoot using the following steps for aircraft and engine fault isolation with reference to the Light Engine Maintenance Manual Subtask 72-00-00-810-278-A01.
- Do close out.
