# SDR ASAA2019080973341

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 7, 2019
- Submitted: August 9, 2019
- Operation: Air carrier
- Aircraft: [N459AS](https://openairdocs.org/aircraft/N459AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 36352
- Aircraft time: 21,644 hours, 7,035 cycles
- System (JASC): [2310 · HF Communications System](https://openairdocs.org/jasc/2310)
- Part: Radio
- Condition: Unknown
- Location: Nr 1 Hf Comms
- Stage of operation: CR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2019080973341

## Discrepancy

HF 1 ACTIVE FREQUENCY SWITCHES ON ITS OWN INTERMITTENTLY WENT FROM TUNED FREQ OF 10057 AND CHANGED TO 20054 5 TIMES DURING THE ETOPS PORTION OF FLIGHT. GROUNDED - YES. UNBALE TO DUPLICATE, ACCOMPISHED HF OPERATIONAL TEST REF B737-900 AMM 23-11-00-710-801 TEST PASSED. ACCOMPLISHED RTP OPERATIONAL TEST REF AMM 23-12-41-400-801.

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