Narrative:

The aircraft was cleared to 10000' by phl departure. The PNF acknowledged and set the altitude preselect to 10000'. As the aircraft climbed through 9700' the PNF stated, 'leveling at 10000'.' the PF initiated a level off, leveled at 10350' then made an immediate descent to 10000'. Phl departure called the aircraft, stating, '...maintain 10000 altimeter 30.01.' PNF responded ' ...leveling 10000'.' at no time was the aircraft in conflict with any other aircraft. A new altitude selector/warning system was installed in this aircraft in 12/90. This system operates as follows. As the aircraft climbs or descends through 1000' before set altitude, the altitude preselect light on the glareshield illuminates. 300' before set altitude the warning tone sounds and the light extinguishes. There is no 'on altitude' indication unless the autoplt is engaged at which time a small annunciator on the glareshield illuminates signaling altitude capture. Both pilots had previous experience with altitude warning systems that sounded and illuminated a warning at 1000' before assigned altitude and extinguihed the warning light 300' prior to assigned altitude. This type of system aurally alerts the crew farther in advance that the aircraft is reaching an assigned altitude. This is imperative with the performance of today's aircraft. Standardization of these systems may help reduce this type of occurrence. Supplemental information from acn 168261. As we climbed through 9000' my eyes and attention were outside the cockpit searching for traffic. At 9700' my copilot, also a type-rated cpr medium large transport captain, called 'leveling 10000'.' I heard the tone and began our level off. I know that with our old system I would not have overshot our assigned altitude. At no time were we in conflict with another aircraft, nor did we endanger our passengers.

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Original NASA ASRS Text

Title: CPR MLG FLC OVERSHOOTS ASSIGNED ALT IN CLIMB.

Narrative: THE ACFT WAS CLRED TO 10000' BY PHL DEP. THE PNF ACKNOWLEDGED AND SET THE ALT PRESELECT TO 10000'. AS THE ACFT CLBED THROUGH 9700' THE PNF STATED, 'LEVELING AT 10000'.' THE PF INITIATED A LEVEL OFF, LEVELED AT 10350' THEN MADE AN IMMEDIATE DSNT TO 10000'. PHL DEP CALLED THE ACFT, STATING, '...MAINTAIN 10000 ALTIMETER 30.01.' PNF RESPONDED ' ...LEVELING 10000'.' AT NO TIME WAS THE ACFT IN CONFLICT WITH ANY OTHER ACFT. A NEW ALT SELECTOR/WARNING SYS WAS INSTALLED IN THIS ACFT IN 12/90. THIS SYS OPERATES AS FOLLOWS. AS THE ACFT CLBS OR DSNDS THROUGH 1000' BEFORE SET ALT, THE ALT PRESELECT LIGHT ON THE GLARESHIELD ILLUMINATES. 300' BEFORE SET ALT THE WARNING TONE SOUNDS AND THE LIGHT EXTINGUISHES. THERE IS NO 'ON ALT' INDICATION UNLESS THE AUTOPLT IS ENGAGED AT WHICH TIME A SMALL ANNUNCIATOR ON THE GLARESHIELD ILLUMINATES SIGNALING ALT CAPTURE. BOTH PLTS HAD PREVIOUS EXPERIENCE WITH ALT WARNING SYSTEMS THAT SOUNDED AND ILLUMINATED A WARNING AT 1000' BEFORE ASSIGNED ALT AND EXTINGUIHED THE WARNING LIGHT 300' PRIOR TO ASSIGNED ALT. THIS TYPE OF SYS AURALLY ALERTS THE CREW FARTHER IN ADVANCE THAT THE ACFT IS REACHING AN ASSIGNED ALT. THIS IS IMPERATIVE WITH THE PERFORMANCE OF TODAY'S ACFT. STANDARDIZATION OF THESE SYSTEMS MAY HELP REDUCE THIS TYPE OF OCCURRENCE. SUPPLEMENTAL INFO FROM ACN 168261. AS WE CLBED THROUGH 9000' MY EYES AND ATTN WERE OUTSIDE THE COCKPIT SEARCHING FOR TFC. AT 9700' MY COPLT, ALSO A TYPE-RATED CPR MLG CAPT, CALLED 'LEVELING 10000'.' I HEARD THE TONE AND BEGAN OUR LEVEL OFF. I KNOW THAT WITH OUR OLD SYS I WOULD NOT HAVE OVERSHOT OUR ASSIGNED ALT. AT NO TIME WERE WE IN CONFLICT WITH ANOTHER ACFT, NOR DID WE ENDANGER OUR PAXS.

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.