Narrative:

We were climbing out of london's heathrow airport in a widebody transport. I was the PF. My position is first officer. There was a captain and relief pilot aboard in the cockpit at the time. After takeoff numerous heading and altitude changes were given. Turn right to 285 degree (after takeoff 9R). Climb to 6000 ft. Then additional step type climbs at the same time additional heading changes. (Our altimeters were set to hectopascal millibars). Through 6000 ft, on our way to 8000 ft the autothrottle system proved inoperative right then a new heading change and climb was given to 10000 ft along with speed our discretion. The glass cockpit workload was high since the captain was manually turning altitude, heading and speed knobs and I, the first officer, was manually controling the throttles and flying. Upon leveling at 10000 london ATC commanded us to turn left and descend to 10000. We told them we were level. At the same time we remembered that 6000 ft was the transition altitude to 1013 hp/29.92 wa. We set our altimeters and found we were 450 ft higher than we thought. No near miss occurred. We apologized to london and they said they would take action. Our airline flys domestic international and the transition altitude is a memory item not included on any of our checklists.

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Original NASA ASRS Text

Title: ACR WDB ALT DEV OVERSHOT DURING CLB OUT AT LHR. FLC FORGOT TO SET ALTIMETERS TO QNH AT 6000 FT.

Narrative: WE WERE CLBING OUT OF LONDON'S HEATHROW ARPT IN A WDB. I WAS THE PF. MY POS IS FO. THERE WAS A CAPT AND RELIEF PLT ABOARD IN THE COCKPIT AT THE TIME. AFTER TKOF NUMEROUS HDG AND ALT CHANGES WERE GIVEN. TURN R TO 285 DEG (AFTER TKOF 9R). CLB TO 6000 FT. THEN ADDITIONAL STEP TYPE CLBS AT THE SAME TIME ADDITIONAL HDG CHANGES. (OUR ALTIMETERS WERE SET TO HECTOPASCAL MILLIBARS). THROUGH 6000 FT, ON OUR WAY TO 8000 FT THE AUTOTHROTTLE SYS PROVED INOPERATIVE RIGHT THEN A NEW HDG CHANGE AND CLB WAS GIVEN TO 10000 FT ALONG WITH SPD OUR DISCRETION. THE GLASS COCKPIT WORKLOAD WAS HIGH SINCE THE CAPT WAS MANUALLY TURNING ALT, HDG AND SPD KNOBS AND I, THE FO, WAS MANUALLY CTLING THE THROTTLES AND FLYING. UPON LEVELING AT 10000 LONDON ATC COMMANDED US TO TURN L AND DSND TO 10000. WE TOLD THEM WE WERE LEVEL. AT THE SAME TIME WE REMEMBERED THAT 6000 FT WAS THE TRANSITION ALT TO 1013 HP/29.92 WA. WE SET OUR ALTIMETERS AND FOUND WE WERE 450 FT HIGHER THAN WE THOUGHT. NO NEAR MISS OCCURRED. WE APOLOGIZED TO LONDON AND THEY SAID THEY WOULD TAKE ACTION. OUR AIRLINE FLYS DOMESTIC INTL AND THE TRANSITION ALT IS A MEMORY ITEM NOT INCLUDED ON ANY OF OUR CHKLISTS.

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.