Narrative:

Our flight departure lhr on sep/mon/97. Flight plan filed via stn direct 60n10w, entering reykjavik airspace near 61n14w, then random track to sfo. Per SOP, I called shanwick radio on 135.52 for oceanic clearance while cruising in scottish ATC domestic control. Shanwick issued the clearance: FL350, mach .84. After reading back the clearance, I gave an estimate of XA55Z for crossing 60n10w (oceanic entry), I then called scottish ATC to notify them of receipt of oceanic clearance, and request for FL350 before 60n10w. Nearing 60n10w, scottish sent us to shanwick radio. On VHF, we read to shanwick all 3 sections of the air rep, verbatim, as displayed on the 'position report' page of the FMC, standard company procedures. The same information is logged on the filed copy of our flight plan. Company dispatch confirms that they received the standard progress call from the shanwick radio operator at XA57Z of our position report. Nearing 61n14w both pilots noted a TCASII at FL350 about 30 NM ahead. Before we could question this, we received an HF radio SELCAL, with a message to immediately descend to FL340. No reason given, although several attempts were required to establish voice contact due to poor quality of HF reception. This message was acknowledged at XB05Z, and we reported FL340 reached at XB06Z. Shortly thereafter, reykjavik control established radar contact. When the ride became choppy, FL350 was approved. No comments were ever passed to us from shanwick radio, iceland radio, or reykjavik control regarding the descend message. On sep/wed/97, chief pilot fleet (B777) phoned me at home to advise that the british civil aviation authority/authorized (caa) had initiated an airprox report investigation. The report states that an occurrence took place between us and a foreign air carrier at approximately 60n12w, FL350, on sep/mon/97 at XB05Z. The airprox further states, 'that we reported passing 60N and 10W 1 hour earlier than expected which resulted in a conflict (airprox) with the foreign air carrier.' subsequent conversations with B777 fleet office and company dispatchers reveal that the radio operator at shanwick is the focus for where the miscom originated. From hearsay only, it seems the radio operator claims that we forwarded the 60n10w estimate as 1 hour earlier than planned (even though we were then only about 30 mins away from 60n10w) and that when he repeated it back, we confirmed his misconnection. While all things are possible, it is highly improbable this occurred due to our company procedures. At all times, we display at least one, and generally four, displays of an upcoming position and ETA. Both left and right FMC 'progress' page or 'legs' pages, and 'data' display on left and right navigation display screens. Additionally, the pilot delivering any report will have the flight plan in hand. Times reflecting ETA's are entered by the third pilot from our generated times on an ACARS 'howgozit' message from company dispatch. And in all cases, any FMC or flight plan entries made by one pilot are independently confirmed by another pilot before acceptance. Compliance is mandatory and whole-heartedly supported by company pilots, so the chance for mistakes is greatly reduced when SOP is strictly complied and enforced. Scuttlebutt has it that the caa feels that both clearance delivery (shanwick radio) and scottish ATC -- who are reported to be in the same room -- should have caught the initial discrepancy. Our position report at XA55, and estimate for the next position, 62n20w, should have triggered both shanwick and iceland radio's attention also. Of course, we are completely unaware of the miscom, even after the descent clearance. The closest approach between us and the foreign air carrier was approximately 20 NM on TCASII displays.

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Original NASA ASRS Text

Title: AN ACR B777 FLC WAS ACCUSED OF CAUSING A CONFLICT BY ARRIVING AT A NAV POINT 1 HR TOO SOON. THE FLC DISPUTES THIS ASSESSMENT AND STATES THAT THEY XMITTED THE TIME CORRECTLY.

Narrative: OUR FLT DEP LHR ON SEP/MON/97. FLT PLAN FILED VIA STN DIRECT 60N10W, ENTERING REYKJAVIK AIRSPACE NEAR 61N14W, THEN RANDOM TRACK TO SFO. PER SOP, I CALLED SHANWICK RADIO ON 135.52 FOR OCEANIC CLRNC WHILE CRUISING IN SCOTTISH ATC DOMESTIC CTL. SHANWICK ISSUED THE CLRNC: FL350, MACH .84. AFTER READING BACK THE CLRNC, I GAVE AN ESTIMATE OF XA55Z FOR XING 60N10W (OCEANIC ENTRY), I THEN CALLED SCOTTISH ATC TO NOTIFY THEM OF RECEIPT OF OCEANIC CLRNC, AND REQUEST FOR FL350 BEFORE 60N10W. NEARING 60N10W, SCOTTISH SENT US TO SHANWICK RADIO. ON VHF, WE READ TO SHANWICK ALL 3 SECTIONS OF THE AIR REP, VERBATIM, AS DISPLAYED ON THE 'POS RPT' PAGE OF THE FMC, STANDARD COMPANY PROCS. THE SAME INFO IS LOGGED ON THE FILED COPY OF OUR FLT PLAN. COMPANY DISPATCH CONFIRMS THAT THEY RECEIVED THE STANDARD PROGRESS CALL FROM THE SHANWICK RADIO OPERATOR AT XA57Z OF OUR POS RPT. NEARING 61N14W BOTH PLTS NOTED A TCASII AT FL350 ABOUT 30 NM AHEAD. BEFORE WE COULD QUESTION THIS, WE RECEIVED AN HF RADIO SELCAL, WITH A MESSAGE TO IMMEDIATELY DSND TO FL340. NO REASON GIVEN, ALTHOUGH SEVERAL ATTEMPTS WERE REQUIRED TO ESTABLISH VOICE CONTACT DUE TO POOR QUALITY OF HF RECEPTION. THIS MESSAGE WAS ACKNOWLEDGED AT XB05Z, AND WE RPTED FL340 REACHED AT XB06Z. SHORTLY THEREAFTER, REYKJAVIK CTL ESTABLISHED RADAR CONTACT. WHEN THE RIDE BECAME CHOPPY, FL350 WAS APPROVED. NO COMMENTS WERE EVER PASSED TO US FROM SHANWICK RADIO, ICELAND RADIO, OR REYKJAVIK CTL REGARDING THE DSND MESSAGE. ON SEP/WED/97, CHIEF PLT FLEET (B777) PHONED ME AT HOME TO ADVISE THAT THE BRITISH CIVIL AVIATION AUTH (CAA) HAD INITIATED AN AIRPROX RPT INVESTIGATION. THE RPT STATES THAT AN OCCURRENCE TOOK PLACE BTWN US AND A FOREIGN ACR AT APPROX 60N12W, FL350, ON SEP/MON/97 AT XB05Z. THE AIRPROX FURTHER STATES, 'THAT WE RPTED PASSING 60N AND 10W 1 HR EARLIER THAN EXPECTED WHICH RESULTED IN A CONFLICT (AIRPROX) WITH THE FOREIGN ACR.' SUBSEQUENT CONVERSATIONS WITH B777 FLEET OFFICE AND COMPANY DISPATCHERS REVEAL THAT THE RADIO OPERATOR AT SHANWICK IS THE FOCUS FOR WHERE THE MISCOM ORIGINATED. FROM HEARSAY ONLY, IT SEEMS THE RADIO OPERATOR CLAIMS THAT WE FORWARDED THE 60N10W ESTIMATE AS 1 HR EARLIER THAN PLANNED (EVEN THOUGH WE WERE THEN ONLY ABOUT 30 MINS AWAY FROM 60N10W) AND THAT WHEN HE REPEATED IT BACK, WE CONFIRMED HIS MISCONNECTION. WHILE ALL THINGS ARE POSSIBLE, IT IS HIGHLY IMPROBABLE THIS OCCURRED DUE TO OUR COMPANY PROCS. AT ALL TIMES, WE DISPLAY AT LEAST ONE, AND GENERALLY FOUR, DISPLAYS OF AN UPCOMING POS AND ETA. BOTH L AND R FMC 'PROGRESS' PAGE OR 'LEGS' PAGES, AND 'DATA' DISPLAY ON L AND R NAV DISPLAY SCREENS. ADDITIONALLY, THE PLT DELIVERING ANY RPT WILL HAVE THE FLT PLAN IN HAND. TIMES REFLECTING ETA'S ARE ENTERED BY THE THIRD PLT FROM OUR GENERATED TIMES ON AN ACARS 'HOWGOZIT' MESSAGE FROM COMPANY DISPATCH. AND IN ALL CASES, ANY FMC OR FLT PLAN ENTRIES MADE BY ONE PLT ARE INDEPENDENTLY CONFIRMED BY ANOTHER PLT BEFORE ACCEPTANCE. COMPLIANCE IS MANDATORY AND WHOLE-HEARTEDLY SUPPORTED BY COMPANY PLTS, SO THE CHANCE FOR MISTAKES IS GREATLY REDUCED WHEN SOP IS STRICTLY COMPLIED AND ENFORCED. SCUTTLEBUTT HAS IT THAT THE CAA FEELS THAT BOTH CLRNC DELIVERY (SHANWICK RADIO) AND SCOTTISH ATC -- WHO ARE RPTED TO BE IN THE SAME ROOM -- SHOULD HAVE CAUGHT THE INITIAL DISCREPANCY. OUR POS RPT AT XA55, AND ESTIMATE FOR THE NEXT POS, 62N20W, SHOULD HAVE TRIGGERED BOTH SHANWICK AND ICELAND RADIO'S ATTN ALSO. OF COURSE, WE ARE COMPLETELY UNAWARE OF THE MISCOM, EVEN AFTER THE DSCNT CLRNC. THE CLOSEST APCH BTWN US AND THE FOREIGN ACR WAS APPROX 20 NM ON TCASII DISPLAYS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.