Narrative:

We were assigned to cross 30 NM southwest of vhp at 11000 ft and 250 KTS. I had previously inserted a pbd (place, bearing, distance) that corresponded to 30 mi southwest of vhp at 10000 ft and 250 KTS. I did this at the captain's suggestion, as recently I have been using a non-profile descent mode in which I exercise more control over the FMS descent. During the descent I made an input that increased the speed to 340 KTS in an effort to increase the rate of descent as we had a 130-150 KT tailwind. A mach .82/340 KT descent is normal for the A310 using our company procedures so that we integrate with other faster aircraft. Usually, when I do a mach .82/340 KT descent, I also insert a pbd 8 NM short of the altitude/airspeed restr so that the aircraft can decelerate to 250 KTS. I failed to do so this time as I initiated the descent at a slower speed. Somewhere during the descent I became concerned, that we weren't going to make the altitude restr. I mistakenly thought this as I was under the impression that the crossing restr was 10000 ft not 11000 ft and my mental calculations had us high at 30 mi southwest of vhp. Consequently, I disconnected the autoplt in effort to increase the rate of descent. Passing through 11150 ft, the captain stated 'there's your altitude (ie, 11000 ft).' I immediately initiated a leveloff but descend to approximately 10750-10725 ft during the leveloff maneuver and slowed to 250 KTS. I believe the fact that I had 250 KTS and 10000 ft inserted in the FMS for about 1 hour prior to the event caused my confusion over the altitude as I had a preconceived notion of what our altitude should be at 30 NM southwest of vhp. I also did not hear the captain state '12000 ft for 11000 ft' as per our company's procedures. He admitted that we were both busy at the time but didn't say whether or not he made the call. Additionally, this was the 4TH night of a 5 night trip and I was somewhat fatigued. I believe that had we confirmed 12000 ft to 11000 ft between us and communicated better all around that this would have been avoided. My doubts as to whether the FMS, autoplt was compensating for the excessive tailwind also contributed to this problem. I should have trusted the FMS.

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Original NASA ASRS Text

Title: FO OF AN A310, AIRBUS, OVERSHOT DSCNT ALT DUE TO DISCONNECTING THE AUTOPLT TO MANUALLY SLOW THE ACFT SPD FOR A XING ALT WHICH HE HAD CONFUSED FOR A LOWER ALT. HE IMMEDIATELY CORRECTED BACK WHEN THE CAPT CALLED OUT REACHING ASSIGNED ALT.

Narrative: WE WERE ASSIGNED TO CROSS 30 NM SW OF VHP AT 11000 FT AND 250 KTS. I HAD PREVIOUSLY INSERTED A PBD (PLACE, BEARING, DISTANCE) THAT CORRESPONDED TO 30 MI SW OF VHP AT 10000 FT AND 250 KTS. I DID THIS AT THE CAPT'S SUGGESTION, AS RECENTLY I HAVE BEEN USING A NON-PROFILE DSCNT MODE IN WHICH I EXERCISE MORE CTL OVER THE FMS DSCNT. DURING THE DSCNT I MADE AN INPUT THAT INCREASED THE SPD TO 340 KTS IN AN EFFORT TO INCREASE THE RATE OF DSCNT AS WE HAD A 130-150 KT TAILWIND. A MACH .82/340 KT DSCNT IS NORMAL FOR THE A310 USING OUR COMPANY PROCS SO THAT WE INTEGRATE WITH OTHER FASTER ACFT. USUALLY, WHEN I DO A MACH .82/340 KT DSCNT, I ALSO INSERT A PBD 8 NM SHORT OF THE ALT/AIRSPD RESTR SO THAT THE ACFT CAN DECELERATE TO 250 KTS. I FAILED TO DO SO THIS TIME AS I INITIATED THE DSCNT AT A SLOWER SPD. SOMEWHERE DURING THE DSCNT I BECAME CONCERNED, THAT WE WEREN'T GOING TO MAKE THE ALT RESTR. I MISTAKENLY THOUGHT THIS AS I WAS UNDER THE IMPRESSION THAT THE XING RESTR WAS 10000 FT NOT 11000 FT AND MY MENTAL CALCULATIONS HAD US HIGH AT 30 MI SW OF VHP. CONSEQUENTLY, I DISCONNECTED THE AUTOPLT IN EFFORT TO INCREASE THE RATE OF DSCNT. PASSING THROUGH 11150 FT, THE CAPT STATED 'THERE'S YOUR ALT (IE, 11000 FT).' I IMMEDIATELY INITIATED A LEVELOFF BUT DSND TO APPROX 10750-10725 FT DURING THE LEVELOFF MANEUVER AND SLOWED TO 250 KTS. I BELIEVE THE FACT THAT I HAD 250 KTS AND 10000 FT INSERTED IN THE FMS FOR ABOUT 1 HR PRIOR TO THE EVENT CAUSED MY CONFUSION OVER THE ALT AS I HAD A PRECONCEIVED NOTION OF WHAT OUR ALT SHOULD BE AT 30 NM SW OF VHP. I ALSO DID NOT HEAR THE CAPT STATE '12000 FT FOR 11000 FT' AS PER OUR COMPANY'S PROCS. HE ADMITTED THAT WE WERE BOTH BUSY AT THE TIME BUT DIDN'T SAY WHETHER OR NOT HE MADE THE CALL. ADDITIONALLY, THIS WAS THE 4TH NIGHT OF A 5 NIGHT TRIP AND I WAS SOMEWHAT FATIGUED. I BELIEVE THAT HAD WE CONFIRMED 12000 FT TO 11000 FT BTWN US AND COMMUNICATED BETTER ALL AROUND THAT THIS WOULD HAVE BEEN AVOIDED. MY DOUBTS AS TO WHETHER THE FMS, AUTOPLT WAS COMPENSATING FOR THE EXCESSIVE TAILWIND ALSO CONTRIBUTED TO THIS PROB. I SHOULD HAVE TRUSTED THE FMS.

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.