03/15/21
Message Overview:
Message Description:
Discrete Input 09A (Gear Extend Monitor2) circuit failed.
Possible Causes:
- Proximity-Sensor Electronic Unit (PSEU) (A9)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Proximity-Sensor Electronic Unit (PSEU) | AMM 32-61-09-000-801 |
| Installation of the Proximity-Sensor Electronic Unit (PSEU) | AMM 32-61-09-400-801 |
| Functional Test of the Proximity-Sensor Electronic Unit (PSEU) | AMM 32-61-09-720-801 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Pull and reset the PSEU gear system breakers (CB1-C13, CB1-C14), (CB2-C13, CB2-C14), recheck the system for the fault.
- Check the PSEU plug, 28 VDC power should be on the following pins: A98BP1_3A, 4A, 3C, 4C, 7K, 8K, 7H, 8H. Grounds < 0.5 VDC should be on the following pins: A9BP1_3H, 4H, 3K, 4K, 7A, 7C, 8C.
- Check the ARINC 429 data bus from the PSEU A9CP1 pins 1B, 2B to IAPS A4P1 pin 61, 62, and PSEU A9CP1 pins 1B, 2B to DCU pins A14DP1 1A, 1B.
- Check the wiring from the PSEU A9BP1 Pin 13A to PL10J/P1 Pin 2 (Landing Gear Control Panel PL10), and from the PSEU A9BP1 pin 15A to V9P1 pin E (Landing Gear Selector Valve V9).
- Re-rack JB4.
- If possible, download and have field service review the PSEU NVM. Further troubleshooting will depend on results of the PSEU NVM.
- If the wiring checks good and the NVM does not identify external inputs as the fault, replace the PSEU IAW AMM TASK 32-61-09-000-801, AMM TASK 32-61-09-400-801.
- Functional check the proximity sensor electronic unit IAW AMM TASK 32-61-09-720-801.
