What was found
DURING FLIGHT, THE CREW NOTED THAT NR 1 HF RADIO WOULD NOT TUNE ON FREQUENCY 13.354. ALL OTHER FREQUENCIES OPERATED NORMALLY. AIRCRAFT LANDED IN OGG WITHOUT FURTHER INCIDENT. MAINTENANCE PERFORMED FIM TASK 23-11-00-810-801 WITH NO DEFECTS NOTED. NR 1 HF RADIO OPERATED NORMALLY ON GROUND. AIRCRAFT WAS RETURNED TO SERVICE. A FLIGHT VERIFICATION WAS PERFORMED FOR THE NR 1 HF SYSTEM. SYSTEM CHECK WAS FOUND NORMAL AND NOTED BY MAINTENANCE. DURING OVERNIGHT, MAINTENANCE REPLACED THE NR 1 HF COUPLER IAW AMM 23-11-61-4 FOR PRECAUTIONARY MEASURE. AIRCRAFT WAS RETURNED TO SERVICE. A FLIGHT VERIFICATION WAS PERFORMED AGAIN FOR THE NR 1 HF SYSTEM. SYSTEM CHECK WAS FOUND NORMAL AND NOTED BY MAINTENANCE.