Pilots reported a HF radio fail and diverted instead of continuing an oceanic flight.
Synopsis
Pilots reported a HF radio fail and diverted instead of continuing an oceanic flight.
Narrative
Loss of enroute communication ability. Aircraft X from ZZZ to ZZZZ - Returned to ZZZ after loss of communication capability. Aircraft X had previous history of SATCOM issues and each time was released after system resets and ground checks. Our flight was normal through takeoff and coast out; and we were able to get a SELCAL check. Initial CPDLC logon and position report sent ZZZ1 without problem. About 12 minutes after passing ZZZZZ; we got a SELCAL from ARINC (Commercial Radio) asking for a position report for ZZZZZ. After several tries due to poor quality of transmission and reception on HF; we were able to provide a standard verbal position report. We tried to send a second manual CPDLC position report; but that message hung up on the 'sending' prompt. Soon after that we got another SELCAL asking us if we were receiving the CPDLC messages from ATC to which we responded no. We then tried to reset CPDLC by manually logging off ZZZ1 then logging on again. That failed with EICAS (Engine Indicating and Crew Alerting System) caution 'SATCOM' and 'DATALINK LOST' messages. There are no checklists to restore functions for these systems. Our next effort was to attempt to contact ATC and/or Dispatch via SAT phone; but both left and right systems showed 'Not Ready' and there were no prompts to initiate calls; it was useless to us. We then tried to contact ARINC on HF again to have them advise ATC that we were unable CPDLC and were planning to continue using voice procedures. Our plan was to also get a phone patch with dispatch to advise and coordinate further action be it continuing or divert. This attempt to establish HF communication with ARINC was unsuccessful on the primary and the secondary frequencies. We could hear them talking but not able to understand. We also tried the previously given 150W frequencies but had no response on either frequency. I think our HF system was probably working OK; it seemed to just be a really bad day for HF communication; I assume to be caused by ionospheric or space weather conditions. Due to SAT failure; ACARS had reverted to HF Datalink and had no useful connectivity either. It would come and go and sometimes deliver messages but usually not. About this time I remembered that we still had IFE (Inflight Entertainment) internet connectivity; and I realized that I might be able to do a WIFI call to dispatch. Airline Wi-fi restricts video streaming and internet calls but I figured I might be able to bypass that restriction like the great Firewall of China using VPN service on my iPhone. I successfully got my VPN to tunnel out and pop up on a ZZZ2 internet node; dialed phone number and dispatch answered! Thankfully this scheme worked great; we ended up having a 1 hour and 37 minute call that was essential to our safe and fully Dispatch/ ATC coordinated return to ZZZ. Throughout the call I was worried that the internet would fail at any time and terminate the call but it worked perfectly the whole time. Dispatcher Name was awesome and set up our first conference with Maintenance who advised us that due to policy; he was unable to provide circuit breaker resets for possibly regaining SAT capability. Upon hearing this; and taking into consideration that my FO (First Officer) was still unable to establish HF communications with ZZZ radio; I was not comfortable continuing across the ocean. We woke up the Relief Pilot; filled him in on the situation and along with Dispatch all of agreed a return to ZZZ was prudent and to not risk further flight with such degraded communication capability. While Dispatch was setting up another conference call; with ZZZ3 Oceanic ATC; I got the Purser on the interphone; advised him of our situation and asked him to come up to the cockpit. Before he could make it up there Dispatch had our conference set up with the ATC supervisor. He was able to coordinate with us in realtime and based upon our verbally given LAT/LONG position; gave us a descent to FL310; then a right 180turn and further clearance back to ZZZ. All three of us pilots were very careful to ensure correct FMC programming during the maneuver. My flying FO did a great job keeping track of the airplane while I was essentially isolated by being the only one able to talk on my cell phone. I tried using speakerphone but it just wasn't loud enough so we were forced into a split cockpit situation. We adapted and things went well. The 180 turn was accomplished in HDG mode at reduced bank angle out of concerns of steeper bank angle upsetting the satellite antenna connection. We were able to complete the turn; engage LNAV; then give the ATC supervisor accurate time estimates for the two intermediate fixes back to ZZZ. All without dropping the call.Once established on the track back home; I passed the phone to my Relief Pilot to maintain communication with dispatch while I briefed the purser. I advised him that we would be having a normal landing in about 2 ½ hours; no evac needed. I then made a PA announcement to the people. Returning to the dispatch call we discussed and decided to NOT declare an emergency with ATC unless we actually did lose the call. In that case dispatch would advise ATC of our emergency status and we would use standard procedures to advise other aircraft and regain ATC communication through all available means including other aircraft relay. We also looked at and discussed the ZZZ landing data with Dispatch and decided that an overweight landing (466k lbs.) using my Captain emergency authority had good safety margins on the runways; especially with the headwinds in ZZZ; and would be the best option compared to dumping fuel. Before terminating the call to Dispatch; I accomplished the applicable items remaining on the diversion guide; and exchanged iMessage texts to ensure continued direct message capability with our dispatcher. The rest of the flight went normally; as we got closer to mainland; we were able to make an HF verbal position report at the first fix going home; and then we were able to establish normal VHF communication with ZZZ3 Center when we reached ZZZZZ1 intersection. The overweight landing was smoothly hand flown and not much braking was needed; the hottest brake afterward was only 1.5. We wrote up the failed equipment and gave Maintenance a print out of our overweight landing conditions page to aid their inspection requirements.
Second reporter narrative
Aircraft X; ZZZ-ZZZZ. Aircraft had several log entities about SATCOM issues in past few day. System check and cleared by Maintenance. Maintenance Release reflected this cleared status. Logged into ZZZ4 GOT CLEARANCE as normal. Departed ZZZ; ZZZ4 didn't auto transfer to ZZZ1 so manually logged into ZZZ1. COMMS established with ZZZ1 near FIR boundary between ZZZZZ and ZZZZZ1 at approximately XA20z. POSITION REPORT SENT. HF SELCAL check was successfully completed with primary/secondary frequencies and 150w frequencies before FIR boundary. ETOPS weather received and EOK sent. Approx XA:58z received a SELCAL from ZZZ radio asking for position report over ZZZZZ. Gave voice position report. Told they had not received auto position report. At about XA:59 we attempted to send a CPDLC POS report. Stalled at sending never sent. A few mins later got a second SELCAL from ZZZ radio asking if we were receiving messages from them and that ATC was trying to contact us. It was at that point we told them we would try a CPDLC reset and try to re-establish CPDLC Logon. That failed. EICAS (Engine Indicating and Crew Alerting System) SATCOM caution message appeared. We tried several attempts at contacting HF with no luck. Very high interference and static (more then normal). Tried primarily and secondary frequencies. Made AIR TO AIR VHF call to relay better HF freq with an aircraft in area. The new HF FREQ was no better. Was able to finally get a position report via HF but extremely bad connection. We had SATCOM EICAS message. SATCOM SYS status message; NO SATCOM LINK; HF DATA MODE RADIO FAILURE; NO HF LINK; NO DATALINK MESSAGE; NO ACARS CONNECTION; LOST SELCAL ABILITY; LOST ATC DATALINK message. Only VHF working and we were out of range for VHF and lost COMMS with aircraft in area on XXX.XX. As a last ditch attempt; Captain decided to try a Wi-Fi call via Company Wi-Fi. Luckily we established a connection via cellphone with Dispatch/Maintenance. Hoping to troubleshoot the issue. We couldn't find a solution to the issue without circuit breakers resetting and that was not an option per Maintenance. Relief Pilot was called to return to flight deck. Due to concerns of total NO COMM and possible loss of Wi-Fi; Dispatch coordinated via conference call with ZZZ1 ATC SUPERVISOR to coordinate a return to ZZZ. ATC SUPERVISOR had us descend to FL310 to avoid traffic and cleared us via right turn to ZZZZZ2 direct ZZZ. He gave us VHF freq at ZZZZZ2. DATALINK was up and down...mostly down. A few ACARS MESSAGES RECEIVED none able to be sent out. Captain ran diversion guide and coordinated with FA's (Flight Attendants) and while back and forth on cell phone to Dispatch and ATC. Had purser up on flightdeck to brief. Relief Pilot assisted in updating FA's and maintaining cell call connection with Dispatch. I continued flying the airplane and monitoring. And running overweight landing data charts. Passengers were updated and safety was maintained at all times. Reaching ZZZZZ2 VHF COMMS re-established. Assigned new route. Accomplished an overweight landing on Runway XXL. Taxied to gate.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.