Date: 201909
Local time of day: 1801-2400
Location: RJAA.Airport, FO
Weather elements / visibility: Thunderstorm
Aircraft: B777 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
ATC / advisory: Center RJJJ
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: We were on arrival to Narita and were cleared the SWAMP G STAR and the ILS Z16L approach. We had descended to FL 150 and was about 50 nm from SWAMP when ATC gave us a clearance to cross SWAMP at 9;000 ft. The fix past SWAMP (VIXEN) has a crossing altitude of 11;000 ft. I read back the clearance to cross SWAMP at 9;000 ft. with no further response from ATC. I have been in Narita a lot; and a clearance below the STAR speeds and altitude restrictions is normal there. The FO (First Officer) was descending to reach 9;000 ft. by SWAMP. Then after a short time; ATC said to comply with the restrictions. I read back this clearance to ATC. The FO was doing the descent and quickly trying to make 9;000 ft. at SWAMP. We crossed SWAMP at 9;000 ft. and as we approached the next fix VIXEN; ATC asked us if we were complying with the restrictions. I replied yes we were. There was no further response from ATC after that. Then we continued the arrival without any further issues.


Second narrative: We had just returned from break and [we] were beginning our descent for landing. There were some TRWs (Thunderstorms) in the vicinity which required ATC clearance to deviate around. Shortly after returning back on course to a fix on the flight plan; ATC gave us a heading. Then another. Then they began issuing descent clearances. At one point they cleared us direct SWAMP. Then; they issued a descent clearance to 9;000 ft. at SWAMP. I took that to mean to descend to and cross SWAMP at 9;000 ft. We put 9;000 in the MCP (Mode Control Panel) window and I started down. In order to cross SWAMP at 9;000 ft.; I had to use FLCH and speed brake. I have only been to NRT about 5 or 6 times in the last year; but it seems common to me that they frequently issue headings; airspeeds and altitudes that do not comport with those on the STAR. So; down I went. Now SWAMP at 9;000 ft. is 2;000 ft. below the next fix altitude which is VIXEN at 11;000 ft. As we got to 9;000 ft. ATC inquired if we were meeting the restrictions and we replied yes; thinking that we were going to be at 9;000 ft. at SWAMP; as per his instruction. After SWAMP; one of the relief pilots questioned whether or not we were actually supposed to descend to 9;000 ft. or had done it prematurely. At this point; I am unclear if we busted our altitude or not. I recall being cleared to 9;000 ft. at SWAMP; but among the four of us there was disagreement.I awoke [very early] the day of the trip. We had two 3 hour breaks enroute but I didn't sleep well on either. At the time of the incident I had been up for the better part of 22 hours. So; my mind could have been less than sharp. As usual in NRT; communication is less than optimum due to both the language and level of communication that is occurring on the frequency. I felt secure enough to validate 9;000 ft. in the MCP window and start down.


Synopsis: Boeing 777 flight crew reported a communication breakdown between flight crew and ATC during initial approach resulting in missing an altitude restriction.