# SDR CALA2025101710231

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 15, 2025
- Submitted: October 17, 2025
- Operation: Air carrier
- Aircraft: [N2639U](https://openairdocs.org/aircraft/N2639U), registered now
- Make and model: Boeing 777-300ER
- Registry model: [Boeing 777-300ER](https://openairdocs.org/model/boeing-777-300er) (OpenAirDocs)
- Aircraft serial: 62650
- Aircraft time: 36,497 hours, 4,001 cycles
- System (JASC): [2300 · Communications System](https://openairdocs.org/jasc/2300)
- Part: Control Panel
- Part number: 570111
- Part serial: 1361
- Condition: Inoperative
- Location: Audio
- Part time: 798,061 hours, 712,084 cycles
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2025101710231

## Discrepancy

OBSERVER ACP INOPERATIVE. CANT CHANGE SELECTED TRANSMIT SWITCH.  ACP FROZEN UNABLE TO SELECT ANY MIC ON OBSERVERS AUDIO CONTROL PANEL.   REMOVED AND REPLACED OBSERVER ACP PER AMM 23-51-01. OPS CHECK GOOD. NO DEFECTS NOTED.  ACFT OKAY TO CONTINUE.

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