What was found
(CAN) FLT EXPERIENCED AN HF SYS FAILURE IN FLIGHT. DUE TO ROUTING INTO NON-WATER THE ACFT HAD TO DIVERT FOR MORE FUEL. FLIGHT CREW APPLIED MEL TO HF SYS. SYSTEM WAS REPAIRED THAT NIGHT, HF TRANSCEIVER, PN 964-0452-011, SN 03975,TSI 378.5, CSI 173 WAS REPLACED IAW AMM 23-11-21 & OPS CHECK C/O IAW AMM 23-11-00.