Narrative:

The last leg of the day (third day on a 4 day trip). Route miami-jacksonville. Initial climb off miami runway 9L to 5000'. With mia departure we were given a climb to 7000' and a return to 360 degree. We were deviating plus or minus 15 degrees to avoid WX buildups. Departure was very busy with other aircraft at 6000'. A standard '6 for 7' altitude callout was made. At the same time we were given a clearance for a turn to 320 degree to join J53. I was xchking the map and the navaids/radial set in when the altitude alerter went off (400' high). I looked at the captain and he asked me to set in our new altitude (or so he thought) of 10000'. I told him that I didn't remember that clearance and he slowed the climb. Meanwhile I queried the ctrl 3 times (over a period of approximately 30 seconds) before he would answer me. He in fact said we were cleared to 7000' but stated 'continue the climb to 16000' (we were at 8000' by this time). The remainder of the flight was uneventful. I believe the controller cleared another aircraft to 10000' immediately after my acknowledgement of our turn to 320 degree to join the arwy. I think the captain heard the 10000' combined with our heading clearance as all one statement due to the frequency congestion. When calls are made in such quick succession a 'break' call by the controller would help distinguish between them. I made a cockpit error by looking at the map during the last 1000' although the captain was so sure he heard the 10000' clearance that he continued to climb through 7000'. The controller's slow response to confirm our altitude clearance after being queried was a factor. Although he was very busy.

Google
 

Original NASA ASRS Text

Title: ALT OVERSHOT DEVIATING TSTMS.

Narrative: THE LAST LEG OF THE DAY (THIRD DAY ON A 4 DAY TRIP). RTE MIAMI-JACKSONVILLE. INITIAL CLB OFF MIAMI RWY 9L TO 5000'. WITH MIA DEP WE WERE GIVEN A CLB TO 7000' AND A RETURN TO 360 DEG. WE WERE DEVIATING PLUS OR MINUS 15 DEGS TO AVOID WX BUILDUPS. DEP WAS VERY BUSY WITH OTHER ACFT AT 6000'. A STANDARD '6 FOR 7' ALT CALLOUT WAS MADE. AT THE SAME TIME WE WERE GIVEN A CLRNC FOR A TURN TO 320 DEG TO JOIN J53. I WAS XCHKING THE MAP AND THE NAVAIDS/RADIAL SET IN WHEN THE ALT ALERTER WENT OFF (400' HIGH). I LOOKED AT THE CAPT AND HE ASKED ME TO SET IN OUR NEW ALT (OR SO HE THOUGHT) OF 10000'. I TOLD HIM THAT I DIDN'T REMEMBER THAT CLRNC AND HE SLOWED THE CLB. MEANWHILE I QUERIED THE CTRL 3 TIMES (OVER A PERIOD OF APPROX 30 SECS) BEFORE HE WOULD ANSWER ME. HE IN FACT SAID WE WERE CLRED TO 7000' BUT STATED 'CONTINUE THE CLB TO 16000' (WE WERE AT 8000' BY THIS TIME). THE REMAINDER OF THE FLT WAS UNEVENTFUL. I BELIEVE THE CTLR CLRED ANOTHER ACFT TO 10000' IMMEDIATELY AFTER MY ACKNOWLEDGEMENT OF OUR TURN TO 320 DEG TO JOIN THE ARWY. I THINK THE CAPT HEARD THE 10000' COMBINED WITH OUR HDG CLRNC AS ALL ONE STATEMENT DUE TO THE FREQ CONGESTION. WHEN CALLS ARE MADE IN SUCH QUICK SUCCESSION A 'BREAK' CALL BY THE CTLR WOULD HELP DISTINGUISH BTWN THEM. I MADE A COCKPIT ERROR BY LOOKING AT THE MAP DURING THE LAST 1000' ALTHOUGH THE CAPT WAS SO SURE HE HEARD THE 10000' CLRNC THAT HE CONTINUED TO CLB THROUGH 7000'. THE CTLR'S SLOW RESPONSE TO CONFIRM OUR ALT CLRNC AFTER BEING QUERIED WAS A FACTOR. ALTHOUGH HE WAS VERY BUSY.

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.