12/29/25
Message Overview:
Message Name:
TR ICU 1A
Message Code:
B3-304262
| Reporting LRU: | Right Engine Thrust Reverser Isolation Control-Unit (R ENG TR ICU) |
| Associated CAS: | None |
| System Description: | 78-30-00 - Thrust Reverser |
| 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 1A.
[MCID 1440]
TR ICU 1A.
An open circuit fault in the TR ICU harness between the TR ICU and the Electronic Control Unit (ECU) Channel A was sensed.
Possible Causes:
- Aircraft Wiring Harness
- Wiring Harness (W1)
- Right Thrust Reverser Isolation Control Unit (ICU) (A116)
- Right Full Authority Digital Engine Control (FADEC) Channel A (A40)/Electronic Control Unit (ECU)
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
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 1440 fault present, troubleshoot using the following steps for aircraft and engine fault isolation with reference to the Light Engine Maintenance Manual Subtask 72-00-00-810-271-A01.
- Do close out.
