# SDR CALA2026041715460

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 15, 2026
- Submitted: April 17, 2026
- Operation: Air carrier
- Aircraft: [N228UA](https://openairdocs.org/aircraft/N228UA), registered now
- Make and model: Boeing 777222
- Aircraft serial: 30556
- Aircraft time: 94,096 hours, 11,099 cycles
- System (JASC): [3400 · Navigation System](https://openairdocs.org/jasc/3400)
- Part: Adiru
- Part number: HG2060AD01
- Part serial: 227
- Condition: Faulty
- Location: Zone 100
- Part time: 109,732 hours, 12,087 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/CALA2026041715460

## Discrepancy

TCAS EICAS AND -TCAS FAI L- ON ND. TRIED L/R CYCL ED. NO HELP. C ALLED TOMC MMSG 34-28801 CAPTURED IN AHM BUT NOT AUTOMATICALLY CORRELATED TO TCAS FAILURE ADVISORY/STATUS. IN FIM THIS MMSG DOES CORRELATE TO OBSERVED TCAS FAILURE. OTHER ADIRU FAULTS CAPTURED IN AHM. SUGGEST REPLACEMENT OF ADIRU ALONG WITH OTHER MAINTENANCE AS DEEMED NECESSARY BY TROUBLESHOOTING. IADLM WEBBER PERF. TCAS SYSTEM BITE REF. AMM 34-45-01. UNABLE TO DUPLICATE FAULT, TCAS SYSTEM OPS CHECKED GOOD. AS PRECAUTIONARY, REMOVED AND REPLACED TCAS COMPUTER REF. AMM 34-45-01. OPS CHECK GOOD.

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