Date: 201907
Location: ZZZZ.ARTCC, FO
Aircraft: B747-400
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
ATC / advisory: Center ZZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Second reporter function: First Officer; Pilot Flying; Relief Pilot
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: I was in the bunk for rest at the time of the event. What I was told [was that] they got an altitude and route clearance CPDLC message but only did the altitude change ; they did not see the route change part in the message and the load prompt did not populate. They received an HF message that ATC intervention to prevent gross navigational era. Not sure if they got new route via HF before or after ATC intervention message. I did view the CPDLC message the load message took quite a while to populate ; one had to stay on that page for a while and wait; very easy to miss or move to another page before it pops up. I would suggest a single clearance at a time via CPDLC not an altitude and change at the same time.


Second narrative: We were delayed 4+ hours at the hotel and another 2+ hours at the aircraft. I was in the jump seat for takeoff and noted that we seemed to achieve V1 slightly later than usual. We had a 3 pilot crew for the 6+45 flight. I took the 1st rest. Shortly after relieving the Captain I became the Pilot Flying. [Pilot Monitoring] had noted that he wanted to do the plotting and radios since he hadn't done that very much so far in his career. We had instructions to contact Oceanic; which [Pilot Monitoring] had made about 6 or more attempts without success. Either shortly before or after successful voice communications we received a CPDLC climb from FL330 to FL350 to be completed by XA:30Z. This message was received at XX:53Z and I confirmed on the VNAV page that FL350 was achievable (max was over FL380) and executed immediately. The message included report maintaining FL350. It also had the verbiage 'ROUTE AND ALTITUDE CHANGE DUE TRAFFIC.' Page 2 of the message had the ARM feature for the altitude for reporting; which I armed. I accepted the instruction; but noted there was no 'routing.' We confirmed each step and confirmed the proper level off and reporting executed.Shortly after this we received a cabin call from our Flight Attendant that the [Planning] had a correction to the weight and balance. We had it slid under the door since we were busy with ATC communications (planning and executing our switch to ZZZZ Oceanic) and oceanic plotting. We were actually about 8 tons heavier than the original weight and balance. I corrected zero fuel weight in the performance in the CDU. [Pilot Monitoring] and I agreed that we could brief the Captain later since this was not urgent. Were 4 tons of fuel ahead and improving and I had only just relieved the Captain approximately 15-20 minutes ago. I did note that this could have affected our ability to climb to FL350 had the difference been greater and it explained the late achievement of V1 on takeoff.We then received a CPDLC inquiry to confirm point after [waypoint]. As we were replying we received SELCAL on HF and replied by voice also that our point after [waypoint] was ZZZZZ. ATC instructed us to change our routing to ZZZZZ1 ZZZZZ2; we made the correction in the LEGS page of the CDU; confirmed the courses and distances correlated to the oceanic chart and executed.Soon thereafter; ATC called and stated they were filing an 'ATC Intervention to prevent a gross navigational error.' ZZZZ further stated that we had acknowledged a route change with ZZZ Oceanic. Further clarification revealed this corresponded to the climb to FL350 message. We searched the CPDLC log; found that received message and confirmed there was no routing included. We noted at this point that the message stated 'ROUTE AND ALTITUDE CHANGE;' but still saw no routing. [Pilot Monitoring] noted that on page 2 of the message we saw the 'ARM' for the altitude reporting and that no 'LOAD' prompt appeared. We exited out and re-entered the received messages and noted that after about a minute; a 'LOAD' prompt appeared. There was still no routing; just a LOAD prompt. We clarified with ATC that we received the altitude change but had no routing attached and inquired regarding clearance after ZZZZZ2. ATC repeated that we acknowledge the message at 1054z and that we could expect further routing from ZZZZ1.I want to emphasize that the message we received at XX:53Z that had us climb to FL350 by XA:30Z and report maintaining showed no routing. When we called up that message later; the 'LOAD' prompt did not appear for over a minute.Page 2 of that CPDLC message should have had better verbiage; such as 'NEW ROUTING ZZZZZ1 ZZZZZ2 ...' Additionally; the LOAD prompt's failure to appear in a timely manner was a significant factor in this failure. Finally; I must acknowledge that I failed to fully contemplate the implications of 'ROUTE AND ALTITUDE CHANGE DUE TRAFFIC' at the time of executing the climb to FL350. I may have been distracted by the weight and balance issue; but I do recall confirming no routing was in the message.I am intrigued to know if ATC has the ability to 'see' via CPDLC that we had complied with the climb; but had not executed the route change. If so; I am further intrigued to know what the implications of 'ATC Intervention' are (I have never heard that phraseology before). If the crew is in jeopardy from an 'ATC Intervention;' I am further intrigued to know why; if ATC did know that we had not complied with the route change; why proceed down the path of 'ATC intervention' rather than simply clarifying/confirming the route with us.


Synopsis: B747-400 flight crew report ATC intervention to prevent gross navigation error due to missing the second portion of revised CPDLC while enroute.