Narrative:

On approach into memphis, tn, we were given a choice of heading directly for the field and descending to 2000 MSL, in order to beat an approaching line of thunderstorms to the field (under visual conditions) or holding and waiting until the large line of storms passed. I elected to descend and go directly to the field in visual conditions. While trying to sight the field visually and stay clear of the approaching storms, I allowed the aircraft to descend to through 2000' to 1760' before I noticed and corrected the deviation from the assigned altitude of 2000'. A number of things contributed to this deviation. This was my first trip as captain on this type aircraft in over 6 months (having been called upon to fly temporarily as captain on it for 2 months). Due to a merger of my own company and another company, this was my first trip in an large transport that had a different flight director, different type altitude alerting system, different type autoplt and different engines than the aircraft I normally flew. (It had been 1 1/2 years since my differences training). I was dividing my attention between outside visual reference and inside cockpit cues. I did not make good use of my other crew members (I could have stayed inside the cockpit using only instrument references while the first officer attempted to visually acquire the field or vise versa).

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Original NASA ASRS Text

Title: ACR LGT OVERSHOOTS ASSIGNED ALT IN DESCENT.

Narrative: ON APCH INTO MEMPHIS, TN, WE WERE GIVEN A CHOICE OF HDG DIRECTLY FOR THE FIELD AND DSNDING TO 2000 MSL, IN ORDER TO BEAT AN APCHING LINE OF TSTMS TO THE FIELD (UNDER VISUAL CONDITIONS) OR HOLDING AND WAITING UNTIL THE LARGE LINE OF STORMS PASSED. I ELECTED TO DSND AND GO DIRECTLY TO THE FIELD IN VISUAL CONDITIONS. WHILE TRYING TO SIGHT THE FIELD VISUALLY AND STAY CLR OF THE APCHING STORMS, I ALLOWED THE ACFT TO DSND TO THROUGH 2000' TO 1760' BEFORE I NOTICED AND CORRECTED THE DEVIATION FROM THE ASSIGNED ALTITUDE OF 2000'. A NUMBER OF THINGS CONTRIBUTED TO THIS DEVIATION. THIS WAS MY FIRST TRIP AS CAPT ON THIS TYPE ACFT IN OVER 6 MONTHS (HAVING BEEN CALLED UPON TO FLY TEMPORARILY AS CAPT ON IT FOR 2 MONTHS). DUE TO A MERGER OF MY OWN COMPANY AND ANOTHER COMPANY, THIS WAS MY FIRST TRIP IN AN LGT THAT HAD A DIFFERENT FLT DIRECTOR, DIFFERENT TYPE ALT ALERTING SYS, DIFFERENT TYPE AUTOPLT AND DIFFERENT ENGS THAN THE ACFT I NORMALLY FLEW. (IT HAD BEEN 1 1/2 YEARS SINCE MY DIFFERENCES TRAINING). I WAS DIVIDING MY ATTN BTWN OUTSIDE VISUAL REFERENCE AND INSIDE COCKPIT CUES. I DID NOT MAKE GOOD USE OF MY OTHER CREW MEMBERS (I COULD HAVE STAYED INSIDE THE COCKPIT USING ONLY INSTRUMENT REFERENCES WHILE THE F/O ATTEMPTED TO VISUALLY ACQUIRE THE FIELD OR VISE VERSA).

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.