# SDR CALA2025071806715

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 15, 2025
- Submitted: July 18, 2025
- Operation: Air carrier
- Aircraft: [N76021](https://openairdocs.org/aircraft/N76021), registered now
- Make and model: Boeing 777224
- Aircraft serial: 39776
- Aircraft time: 66,785 hours, 6,662 cycles
- System (JASC): [2300 · Communications System](https://openairdocs.org/jasc/2300)
- Part: Sdu
- Part number: 8220314102
- Part serial: 932
- Condition: Faulted
- Location: Zone 200
- Part time: 722,164 hours, 703,733 cycles
- Stage of operation: CL
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2025071806715

## Discrepancy

FLT CREW REPORTS ACARS NOT WORKING, REPORTS CPDLC INOP.  ACP DCMF SYS TEST, AMIS OPS TEST IAW AMM 23-27-00-740-801, 31-41-00- 710-801. HUI REPLACED LEFT AIMS M001 MODULE & OPS TEST CHEKED OK.   R & R RT M001 MODULE, INSTALLED SOFTWARE, OPS CHECK GOOD. REF AMM 31-41-02-400-801.  R & R SDU, UPDATED SOFTWARE, GROUND TEST PASSED. REF AMM 23-15-10-400-801.  FOUND SATCOM SDU FAULT BEFORE & SDU OK AFTER REPLACEMENT . DCMF FUNTION SYSTEM OPS TEST CHECKED OK IAW AMM TASK 23-27-00-740-801 & CPDLC/ADS-C - OPS TEST CHECKED OK IAW AMM TASK 23-27-00-710-801-C1.

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