# SDR CALA2026070517556

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 4, 2026
- Submitted: July 6, 2026
- Operation: Air carrier
- Aircraft: [N37554](https://openairdocs.org/aircraft/N37554), registered now
- Make and model: Boeing 737-9
- Registry model: [Boeing 737-9](https://openairdocs.org/model/boeing-737-9) (OpenAirDocs)
- Aircraft serial: 67578
- Aircraft time: 12,177 hours, 4,010 cycles
- System (JASC): [2310 · HF Communications System](https://openairdocs.org/jasc/2310)
- Part: Transceiver
- Part number: 9640452012
- Condition: Faulted
- Location: Nr 2 Hf
- Stage of operation: CL
- How discovered: O
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2026070517556

## Discrepancy

ACFT RETURNED TO FIELD DUE BOTH HF RADIO ISSUES. CAPT NOTED ON D EBRIEF THAT ON CLIMBOUT, THEY BEGAN TO CHECK BOTH HF ON DIFFEREN T FREQUENCIES AND ALL THEY HEARD WAS STATIC. THEY TRIED MULTIPLE TIMES AT LEAST 10X. ON THE RETURN SEGMENT, THEY TRIED HF1 AGAIN AND IT WORKED FINE. THERE WAS CONVERSATION BETWEEN CREWS AND TO MC THAT A POSSIBLE SOLAR FLAIR MAY HAVE CONTRIBUTED TO THE ANOMA LY.  BITE BOTH HF TRANSCIEVERS - #1 AND #2 HF BITE TEST PASSED. REF AMM TASK 23-11-21-400-801. AS PRECAUTION PERFORM AC TO AC HF RADIO CK - (6000) FREQ. TO VERIFY HF'S COM CK OK. (UNABLE TO CK AT TERM AC MOVED TO MOC). OPS CHECK GOOD ON HF1 AND HF2, AC TO AC COMMUNICATION WAS CLEAR. COULD NOT RECREATE ISSUE.  HF2 TRANCEIVER WAS REPLACED AS A PRECAUTION. REPLACEMENT OF HF1 TRANSCEIVER STILL NEEDED. COUPLER ALSO NIS AT SFO. REF AMM 23-11-21/401, AMM 23-11-00-710-801 AMM 23-11-00-730-801.  PERFORMED OPS.CK.  OF HF1, TEST PASSED. NO NEED OF REPLACING #1 TRANSCEIVER AT THIS  TIME.  REF AMM-23-11-21-400-801

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