EQUIP PROBLEM PLUS A COMS MIXUP CAUSE WDB TO APCH A RPTING POINT A HR EARLY.

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I WAS FLYING WDB CLBING OUT OF HEATHROW; BOUND FOR NYC. CAPT (PNF) WAS CALLING SHANWICK OCEANIC CLRNC FOR OUR CLRNC ACROSS THE N ATLANTIC. I WAS FLYING AND TALKING TO THE LCL HIGH SECTOR CTLR. WHILE THE CAPT WAS GETTING HIS CLRNC; THE OCEANIC CTLR ASKED HIM TO ESTIMATE OUR OCEANIC ENTRY POINT (ACKIL); (54N 10W). BECAUSE THE ACFT CLOCK WAS A DRUM/DIGITAL TYPE; THE HOURS SET OF NUMBERS HAD ROTATED; AT ABOUT 55 MINS PAST INSTEAD OF 59 PAST (OR 00). THE CAPT MISTAKENLY GAVE OCEANIC; A WRONG ESTIMATE OF TIME. OCEANIC ACCEPTED THIS TIME ESTIMATE. THE CAPT CHANGED FREQ BACK TO THE LCL HIGH SECTOR RADAR CTLR. SHORTLY THEREAFTER; THE RADAR CTLR QUIZZED US ABOUT OUR ESTIMATION OF ACKIL. RECHKING THIS; THE CAPT CORRECTED HIS MISTAKE; TO THE RADAR CTLR; WHO SAID HE WOULD PASS IT ON TO OCEANIC. FOR SOME REASON HE DID NOT DO THIS; SO WHEN WE SHOWED UP; ON THE OCEANIC CTLRS FREQ HE WAS SURPRISED; AND HAD TO ISSUE US A CLB CLRNC FROM FL350 TO FL390 BECAUSE OF CONFLICTING TFC (WE WERE VFR CONDITIONS ON TOP). CONTRIBUTING TO THIS INCIDENT WAS THE FACT THAT WE HAD TRANSVERSED SO MANY TIME ZONES IN 24 HRS; IT WAS A TIME CHANGE FROM DAYLIGHT TO STANDARD IN US; WE WERE USING UTC NOT LCL; ETC. I ALSO THINK THE MECHANICAL TIME CLOCK IN THE COCKPIT IS AN ADDITIONAL FACTOR; SINCE THE HOUR DRUM OF NUMBERS ROTATED TO THE NEXT HOUR; BEFORE THE LAST HOUR WAS FINISHED.