Narrative:

On departure controller gave us a turn to a heading, then direct modena, and cleared to 11000'. I was hand flying aircraft, captain was talking to ATC, and setting mode control panel, including altitude select, and selected 'direct' on FMC. Captain read back clearance to 11000', set heading and FMC, and reset altitude select to 11000'. There was a broken deck between 5000 and 8000' that we had flown through on arrival that was bumpy and icey. We had discussed the WX on the ground and the captain had advised the attendants to remain seated until he called and we also wanted the anti ice on prior to entering the clouds. We climbed through the deck and completed the checklists. Through about 10000', but still climbing, departure control switched us to center frequency. As we leveled off at 11000', captain checked in at 11000'. Center asked for altitude confirmation which we gave as 11000'. There was a long pause. Center controller then said that he expected us to be at 10000', but to stay at 11000' and that there was no traffic conflict. Captain stated that he had understood clearance to be 11000' and had read back 11000' west/O any objection by departure controller who issued clearance. Center responded that it's 'always supposed to be 10000'.' naturally, we didn't have that information. I don't know if we misunderstood/misheard the altitude clearance, if approach control misstated the cleared altitude, or if approach control/center had a misunderstanding. The only thing that I can suggest is that level off not be assigned at either 10000' or 11000' so that the altitude readout on the ground would not be obscured by the reduced climb rate after 10000' as the aircraft is accelerated to climb speed.

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Original NASA ASRS Text

Title: MLG CLIMBED TO 11000' INSTEAD OF THE CLEARED ALT OF 10000'.

Narrative: ON DEP CTLR GAVE US A TURN TO A HDG, THEN DIRECT MODENA, AND CLRED TO 11000'. I WAS HAND FLYING ACFT, CAPT WAS TALKING TO ATC, AND SETTING MODE CTL PANEL, INCLUDING ALT SELECT, AND SELECTED 'DIRECT' ON FMC. CAPT READ BACK CLRNC TO 11000', SET HDG AND FMC, AND RESET ALT SELECT TO 11000'. THERE WAS A BROKEN DECK BTWN 5000 AND 8000' THAT WE HAD FLOWN THROUGH ON ARR THAT WAS BUMPY AND ICEY. WE HAD DISCUSSED THE WX ON THE GND AND THE CAPT HAD ADVISED THE ATTENDANTS TO REMAIN SEATED UNTIL HE CALLED AND WE ALSO WANTED THE ANTI ICE ON PRIOR TO ENTERING THE CLOUDS. WE CLBED THROUGH THE DECK AND COMPLETED THE CHKLISTS. THROUGH ABOUT 10000', BUT STILL CLBING, DEP CTL SWITCHED US TO CENTER FREQ. AS WE LEVELED OFF AT 11000', CAPT CHKED IN AT 11000'. CENTER ASKED FOR ALT CONFIRMATION WHICH WE GAVE AS 11000'. THERE WAS A LONG PAUSE. CENTER CTLR THEN SAID THAT HE EXPECTED US TO BE AT 10000', BUT TO STAY AT 11000' AND THAT THERE WAS NO TFC CONFLICT. CAPT STATED THAT HE HAD UNDERSTOOD CLRNC TO BE 11000' AND HAD READ BACK 11000' W/O ANY OBJECTION BY DEP CTLR WHO ISSUED CLRNC. CENTER RESPONDED THAT IT'S 'ALWAYS SUPPOSED TO BE 10000'.' NATURALLY, WE DIDN'T HAVE THAT INFO. I DON'T KNOW IF WE MISUNDERSTOOD/MISHEARD THE ALT CLRNC, IF APCH CTL MISSTATED THE CLRED ALT, OR IF APCH CTL/CENTER HAD A MISUNDERSTANDING. THE ONLY THING THAT I CAN SUGGEST IS THAT LEVEL OFF NOT BE ASSIGNED AT EITHER 10000' OR 11000' SO THAT THE ALT READOUT ON THE GND WOULD NOT BE OBSCURED BY THE REDUCED CLB RATE AFTER 10000' AS THE ACFT IS ACCELERATED TO CLB SPD.

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.