Narrative:

Takeoff and departure were normal. The WX was good, however, there were buildups in the area. At the time of the incident we were trying to navigation around a buildup using radar. Just prior to level off at 13000' the aircraft entered the top of a buildup experiencing moderate turbulence, heavy rain and st elmo's fire. The captain, who was flying at the time, was adjusting the rate of climb for an autocapture when the build up was entered. His attention was diverted to the automatic throttles and trying to slow to turbulence penetration speed. Since there was heavy rain, ignition was called for. Suddenly the altitude alerter called out 'altitude.' we were still climbing through 13000' and passing 13300'. Action was taken to reverse the climb, but the aircraft reached 13500' before a reversal was achieved. Center advised that mode C readout showed 13400', however by that time we'd reached our original level off altitude of 13000'. We reported level at 13000'. The cause of the incident was the selection of vertical speed during autocapture, thus cancelling the autocapture. Also the diversion of the captain's attention to speed reduction and the handoff from departure to center during level off caused the crew to not xchk the flight mode annunciator and monitor the level off. Contributing to the incident were the first officer's relative inexperience both in total time and in type of equipment. We were both taken by surprise when we entered the buildup, however he seemed frozen and mesmerized by what was happening outside. I don't think he'd ever seen st elmo's fire before. As I'd find out later, he didn't have much experience with the particular model we were operating. With the relatively complex instrumentation and autothrottles, it takes a good operational knowledge of how the equipment works. This model constitutes less than 20% of our fleet and it's not uncommon to not fly this particular model for 2 weeks or to fly 3 different models in 1 day. Finally, the perfect timing of all the events occurring at once multiplied all the factors leading up to the event. Better crew coordination and experience in the aircraft could have possibly prevented the incident. Also the need for the PF to do just that, ie, try not to do too much at once. The speed reduction could have waited until the level off was achieved and the radio call could have been postponed until the situation was under control.

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Original NASA ASRS Text

Title: ACR MLG ALT DEVIATION OVERSHOT CRUISE ALT.

Narrative: TKOF AND DEP WERE NORMAL. THE WX WAS GOOD, HOWEVER, THERE WERE BUILDUPS IN THE AREA. AT THE TIME OF THE INCIDENT WE WERE TRYING TO NAV AROUND A BUILDUP USING RADAR. JUST PRIOR TO LEVEL OFF AT 13000' THE ACFT ENTERED THE TOP OF A BUILDUP EXPERIENCING MODERATE TURB, HVY RAIN AND ST ELMO'S FIRE. THE CAPT, WHO WAS FLYING AT THE TIME, WAS ADJUSTING THE RATE OF CLB FOR AN AUTOCAPTURE WHEN THE BUILD UP WAS ENTERED. HIS ATTN WAS DIVERTED TO THE AUTO THROTTLES AND TRYING TO SLOW TO TURB PENETRATION SPD. SINCE THERE WAS HVY RAIN, IGNITION WAS CALLED FOR. SUDDENLY THE ALT ALERTER CALLED OUT 'ALT.' WE WERE STILL CLBING THROUGH 13000' AND PASSING 13300'. ACTION WAS TAKEN TO REVERSE THE CLB, BUT THE ACFT REACHED 13500' BEFORE A REVERSAL WAS ACHIEVED. CENTER ADVISED THAT MODE C READOUT SHOWED 13400', HOWEVER BY THAT TIME WE'D REACHED OUR ORIGINAL LEVEL OFF ALT OF 13000'. WE RPTED LEVEL AT 13000'. THE CAUSE OF THE INCIDENT WAS THE SELECTION OF VERT SPD DURING AUTOCAPTURE, THUS CANCELLING THE AUTOCAPTURE. ALSO THE DIVERSION OF THE CAPT'S ATTN TO SPD REDUCTION AND THE HDOF FROM DEP TO CENTER DURING LEVEL OFF CAUSED THE CREW TO NOT XCHK THE FLT MODE ANNUNCIATOR AND MONITOR THE LEVEL OFF. CONTRIBUTING TO THE INCIDENT WERE THE F/O'S RELATIVE INEXPERIENCE BOTH IN TOTAL TIME AND IN TYPE OF EQUIP. WE WERE BOTH TAKEN BY SURPRISE WHEN WE ENTERED THE BUILDUP, HOWEVER HE SEEMED FROZEN AND MESMERIZED BY WHAT WAS HAPPENING OUTSIDE. I DON'T THINK HE'D EVER SEEN ST ELMO'S FIRE BEFORE. AS I'D FIND OUT LATER, HE DIDN'T HAVE MUCH EXPERIENCE WITH THE PARTICULAR MODEL WE WERE OPERATING. WITH THE RELATIVELY COMPLEX INSTRUMENTATION AND AUTOTHROTTLES, IT TAKES A GOOD OPERATIONAL KNOWLEDGE OF HOW THE EQUIP WORKS. THIS MODEL CONSTITUTES LESS THAN 20% OF OUR FLEET AND IT'S NOT UNCOMMON TO NOT FLY THIS PARTICULAR MODEL FOR 2 WKS OR TO FLY 3 DIFFERENT MODELS IN 1 DAY. FINALLY, THE PERFECT TIMING OF ALL THE EVENTS OCCURRING AT ONCE MULTIPLIED ALL THE FACTORS LEADING UP TO THE EVENT. BETTER CREW COORD AND EXPERIENCE IN THE ACFT COULD HAVE POSSIBLY PREVENTED THE INCIDENT. ALSO THE NEED FOR THE PF TO DO JUST THAT, IE, TRY NOT TO DO TOO MUCH AT ONCE. THE SPD REDUCTION COULD HAVE WAITED UNTIL THE LEVEL OFF WAS ACHIEVED AND THE RADIO CALL COULD HAVE BEEN POSTPONED UNTIL THE SITUATION WAS UNDER CTL.

Data retrieved from NASA's ASRS site as of August 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.