Date: 202101
Local time of day: 1801-2400
Location: UAAA.ARTCC, FO
Flight conditions: VMC
Weather elements / visibility: 2400
Light: Night
Aircraft: Boeing Company Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight phase: Cruise
Airspace: Class A UAAA
Aircraft component: Communication Systems
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Second reporter function: Other / Unknown
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Landed As Precaution
Contributing factors: ATC Equipment / Nav Facility / Buildings; Aircraft; Airspace Structure; Software and Automation
Primary problem: ATC Equipment / Nav Facility / Buildings

Narrative: While enroute on a flight plan including an ZZZZ segment; we had a complete data link failure; to include ACARS; CPDLC (Controller Pilot Data Link Communications); SATCOM; VHF DATA; HF DATA; and SATCOM voice. We received multiple EICAS messages along with status messages including CMU (Communications Management Unit). We attempted communication with the company via JETCOM; but we were out of range of available facilities. The [Relief Officer] attempted to connect to ARINC for a phone patch to company; but was unsuccessful. We were unable RNP-XX (Required Navigation Performance); a requirement for the upcoming airspace on our filed route. Another consideration was a SIGMET for severe turbulence along our route. We attempted to get an update through ATC; but were unable to. We attempted communication with ZZZ via HF; but could not contact them. I made the recommendation to continue until VHF communication with ZZZ was established giving us an opportunity to coordinate an RNP-XY route. The PIC (Pilot In Command) was not comfortable continuing and felt the most conservative course of action was a divert into Almaty. Almaty is an approved airport for our aircraft; however it was not on our flight plan and we had no communication with company to obtain an ARTR. The PIC and [Relief Pilot]; both with XX+ years each with the company; felt this was the prudent course of action. We continued as a crew and landed at Almaty without an amended flight release. Flight Operations Manual contains a note (for the [Aircraft] fleet) advising if no DATALINK; to attempt to continue and coordinate via VHF voice. It also says to reference fleet specific ORCA (Oceanic Route Clearance Communications) requirements. There was no guidance in the ORCA guide for this circumstance [for our aircraft]. Given the general difficulty of communication in that region; even with all systems operating normally; this would present an additional challenge. Further clarification in the fleet ORCA guide would be greatly beneficial. While likely not feasible; additional JETCOM coverage would have greatly helped as well.


Second narrative: Lost the following equipment: HF data L & R Satcom voice Satcom data Datalink system / lost CMU (Communications Management Unit). We lost datalink prior to the ZZZZ remote continental route. We were unable to obtain communications with any applicable air control facilities to update information on the reported severe turbulence in our paperwork or coordinate alternate RNPXY (Required Navigation Performance) routing north of the XXXX route so we diverted into ZZZZ1 prior to reaching the remote continental RNP-XX airspace.


Synopsis: Air Carrier Flight Crew reported loss of communications inflight causing a diversion.