# SDR CALA2013081390406

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 11, 2013
- Submitted: August 14, 2013
- Operation: Air carrier
- Aircraft: [N221UA](https://openairdocs.org/aircraft/N221UA), registered now
- Make and model: Boeing 777222
- Aircraft serial: 30552
- Aircraft time: 51,388 hours, 6,366 cycles
- Engine: Pwa PW40903
- System (JASC): [2310 · HF Communications System](https://openairdocs.org/jasc/2310)
- Part: Coupler
- Part number: 490S1
- Part serial: 27873
- Condition: Faulty
- Location: Hf Radio
- Stage of operation: NR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2013081390406

## Discrepancy

HF RADIO - TRANSMISSION PROBLEM.  LT HF INTERMITTENT TRANSMIT ON VARIOUS SELECTED FREQENCIES CANNOT HEAR SIDE TONE.  REPLACED LT HF COUPLER AND VOICE CALL FROM LT HF TO SF.

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