Date: 201809
Local time of day: 1801-2400
Location: VHHH.Airport, FO
Aircraft: B777 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
ATC / advisory: Center VHHK
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Confusion; Situational Awareness; Communication Breakdown
Second reporter function: Pilot Not Flying; Relief Pilot; First Officer
Anomaly: ATC Issue All Types; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Flight Crew Returned To Clearance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: Departing Hong Kong we were climbing to an initial altitude assigned by ATC. The controller had us on radar vectors and we were told to 'expect' 6;900 meters. We confirmed that we would expect 6;900 meters. Shortly after the controller said what we believed was 'Quit Climb' so I pressed the altitude hold switch to stop our climb. The aircraft pitched the nose over slightly to capture the altitude we were at when the altitude hold switch was pushed. The controller once again stated what we thought was 'Quit climb; quit climb' so we responded saying that we have stopped our climb. The controller then responded in a slightly agitated tone 'Aircraft X; I show you descending; Quit Climb.' At this point we asked the controller for clarification and he responded with 'Quit Climb to 6;900 meters.' We then realized that what he actually was asking for was an expedited climb (he may have been saying 'Quick Climb') to 6;900 meters. The non-standard ATC phraseology coupled with the heavy accent of the controller had caused a large communication error resulting in a level off at an altitude that was not requested by ATC.At this time we believe that this was caused due to the use of Non-Standard ATC phraseology in combination with the strong accent of the controller. These two factors made the departure a very confusing situation. If we queried the controller even more than we did it is possible that we may have understood the ATC instructions more clearly. Even hours after the event us four flight crew members cannot say with certainty whether he was saying 'Quit Climb' or 'Quick Climb.'


Second narrative: We were cleared to depart VHHH via BEKO3A RNAV SID. So the pilots operating set the departure and during the preflight briefing we agreed that considering the high volume of workload and entering the China Airspace shortly after departure; it is better that the [relief pilot] ( myself) to contact Gouangzhou Control and give them the ETA to BEKOL waypoint and makes the initial contacts. So shortly after takeoff; I start to working on that radio contact as we were agreed to. Before I switch my radio from Com1; I heard KH departure told us expect 6900 meters. While I was trying to contact Gouangzhou (considering high radio congestion took few minutes to get hold of them) I saw that the PF (Pilot Flying) (FO [First Officer]) pressed the HOLD bottom on MCP which seemed unusual to me during departure. So I immediately switched the radio to Com1 to find out what is happening. I heard the controller was saying that 'My radar shows you descending; quit climb; quit climb'. At that point PM (Pilot Monitoring) (CAP [Captain]) asked him for clarification if he is asking for 'Quit' climb or 'Quick' climb. Which at that point we realized he meant Quick climb. This misunderstanding could be eliminated if the controller was using the official aviation terminology such as 'Expedite' climb. In my opinion language barrier and radio congestion caused it. No proper terminology usage from the controller.Confirming the instruction before read back is the best way to avoid this kinds of misunderstandings.


Synopsis: B777 flight crew reported experiencing an altitude deviation during departure from VHHH airport.  ATC phraseology and language barrier problems were cited as contributing factors.