As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 AND 2 HF RADIO NO COMM APPROACHING GATEWAY FIX. SEEMED TO BE TUNING, HAD SIDETONE. COULDNT HEAR MUCH STATIC IN AUDIO, SEEMED ABNORMAL. ACFT GROUNDED. PERFORMED FIM 23-11 TASK 801, NR 1 AND 2 HF BITE PASSED. PERFORMED HF COMM SYSTEM TEST IAW FIM 23-11 TASK 806. WHILE SWITCH FREQUENCY HF 1 FAILED. REMOVED AND REPLACED THE NR 1 HF COUPLER IAW AMM 23-11-61. NR 1 AND 2 HF OPS CHECKED NORMAL.