Narrative:

Departed day on runway 36 and assigned 10,000' on runway heading. ATC requested turn to 270 degree. We were unable due to thunderstorm line left of us extending 20 NM north. We had to turn right to 010 degree to evade storms visually. ATC kept asking us to turn west as soon as possible for traffic. We responded on several occasions that we were unable. While both pilots' attention was fixed on visually avoiding the storms, our altitude increased to 10,500. Our medium large transport (2) has an altitude alerter unlike the ones installed on other X airline aircraft. The medium large transport (2) gives only a single chime if altitude is deviated by 300' or more. The yellow altitude alert light flashes until the selected altitude is regained, +/-300'. Our other aircraft have a far superior system in that the alerter chimes continuously until the selected altitude is regained, +/-300'. With the volume of conversation we had with approach, combined with our eyes fixed outside, it was easy to miss the single chime, and it took too much time to notice the flashing alert lights. I suggest modifying medium large transport (2 and 3) altitude alerters to mirror those on medium large transport 1 modes.

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Original NASA ASRS Text

Title: MLG MISSES ALT ASSIGNMENT ON CLIMB. WX AND ACFT EQUIPMENT DIFFERENCES LAY A ROLE.

Narrative: DEPARTED DAY ON RWY 36 AND ASSIGNED 10,000' ON RWY HDG. ATC REQUESTED TURN TO 270 DEG. WE WERE UNABLE DUE TO TSTM LINE LEFT OF US EXTENDING 20 NM N. WE HAD TO TURN RIGHT TO 010 DEG TO EVADE STORMS VISUALLY. ATC KEPT ASKING US TO TURN W ASAP FOR TFC. WE RESPONDED ON SEVERAL OCCASIONS THAT WE WERE UNABLE. WHILE BOTH PLTS' ATTN WAS FIXED ON VISUALLY AVOIDING THE STORMS, OUR ALT INCREASED TO 10,500. OUR MLG (2) HAS AN ALT ALERTER UNLIKE THE ONES INSTALLED ON OTHER X AIRLINE ACFT. THE MLG (2) GIVES ONLY A SINGLE CHIME IF ALT IS DEVIATED BY 300' OR MORE. THE YELLOW ALT ALERT LIGHT FLASHES UNTIL THE SELECTED ALT IS REGAINED, +/-300'. OUR OTHER ACFT HAVE A FAR SUPERIOR SYSTEM IN THAT THE ALERTER CHIMES CONTINUOUSLY UNTIL THE SELECTED ALT IS REGAINED, +/-300'. WITH THE VOLUME OF CONVERSATION WE HAD WITH APCH, COMBINED WITH OUR EYES FIXED OUTSIDE, IT WAS EASY TO MISS THE SINGLE CHIME, AND IT TOOK TOO MUCH TIME TO NOTICE THE FLASHING ALERT LIGHTS. I SUGGEST MODIFYING MLG (2 AND 3) ALT ALERTERS TO MIRROR THOSE ON MLG 1 MODES.

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.