Narrative:

Event arose on climb out to VFR on top to commercial maneuvers. Ceiling was reported lower than it actually was. Student in a commercial/instrument part 141 program, and I was attempting to show him some actual IFR en route to commercial maneuvers training. Filed IFR to pohll intersection to reach VFR on top -- a common local occurrence. There were several layers and they were not solid. Controller cleared us to lan 360/15 climb to 6000 ft if not on top at 6000 ft advise. Clearance was read back. A few mins later controller asked if we wanted our clearance limit to be pohll. We answered we could go further north to cutty intersection if it would help. Controller said ok, well turn to heading 360 degrees for a vector and climb to VFR on top. I took this to mean our 6000 ft level off was gone. We continued climb to approximately 6500-6800 ft. Controller asked if we were VFR. I replied in and out of clouds but not on top. A few seconds later we broke out on top approximately 6800 ft and cancelled IFR. Climbed to VFR altitude for cloud clearance. Upon returning I had a note to call departure control supervisor. He informed me that my clearance prior to cancel was 6000 ft and that I should have leveled off. He said the area was clear of aircraft so there was not a critical problem. I explained how I understood the clearance to read and that I thought I had read back 'roger, vectors to on top' which nullified the 6000 ft limit, and that at 6000 ft we were not VMC, so I continued the climb to VMC. He said 'ok, now I think I understand what happened, ok....' he said there was no problem, but for future reference he wanted to point it out. What I learned from this is if there is an altitude limit set, and a new set of instructions are received, verify the altitude limit. I believe the whole thing boiled down to a miscom between ATC and myself, where we both heard what we wanted to hear. I still an not sure, looking back, about what the actual wording of the clearance and my readback was. The conditions were no factor, it was smooth IMC and there were no distrs. The student (flying) was doing fine.

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Original NASA ASRS Text

Title: INSTRUCTOR WITH STUDENT MISINTERPRETS CLRNC, CLBS ABOVE ASSIGNED ALT.

Narrative: EVENT AROSE ON CLBOUT TO VFR ON TOP TO COMMERCIAL MANEUVERS. CEILING WAS RPTED LOWER THAN IT ACTUALLY WAS. STUDENT IN A COMMERCIAL/INST PART 141 PROGRAM, AND I WAS ATTEMPTING TO SHOW HIM SOME ACTUAL IFR ENRTE TO COMMERCIAL MANEUVERS TRAINING. FILED IFR TO POHLL INTXN TO REACH VFR ON TOP -- A COMMON LCL OCCURRENCE. THERE WERE SEVERAL LAYERS AND THEY WERE NOT SOLID. CTLR CLRED US TO LAN 360/15 CLB TO 6000 FT IF NOT ON TOP AT 6000 FT ADVISE. CLRNC WAS READ BACK. A FEW MINS LATER CTLR ASKED IF WE WANTED OUR CLRNC LIMIT TO BE POHLL. WE ANSWERED WE COULD GO FURTHER N TO CUTTY INTXN IF IT WOULD HELP. CTLR SAID OK, WELL TURN TO HDG 360 DEGS FOR A VECTOR AND CLB TO VFR ON TOP. I TOOK THIS TO MEAN OUR 6000 FT LEVEL OFF WAS GONE. WE CONTINUED CLB TO APPROX 6500-6800 FT. CTLR ASKED IF WE WERE VFR. I REPLIED IN AND OUT OF CLOUDS BUT NOT ON TOP. A FEW SECONDS LATER WE BROKE OUT ON TOP APPROX 6800 FT AND CANCELLED IFR. CLBED TO VFR ALT FOR CLOUD CLRNC. UPON RETURNING I HAD A NOTE TO CALL DEP CTL SUPVR. HE INFORMED ME THAT MY CLRNC PRIOR TO CANCEL WAS 6000 FT AND THAT I SHOULD HAVE LEVELED OFF. HE SAID THE AREA WAS CLR OF ACFT SO THERE WAS NOT A CRITICAL PROB. I EXPLAINED HOW I UNDERSTOOD THE CLRNC TO READ AND THAT I THOUGHT I HAD READ BACK 'ROGER, VECTORS TO ON TOP' WHICH NULLIFIED THE 6000 FT LIMIT, AND THAT AT 6000 FT WE WERE NOT VMC, SO I CONTINUED THE CLB TO VMC. HE SAID 'OK, NOW I THINK I UNDERSTAND WHAT HAPPENED, OK....' HE SAID THERE WAS NO PROB, BUT FOR FUTURE REF HE WANTED TO POINT IT OUT. WHAT I LEARNED FROM THIS IS IF THERE IS AN ALT LIMIT SET, AND A NEW SET OF INSTRUCTIONS ARE RECEIVED, VERIFY THE ALT LIMIT. I BELIEVE THE WHOLE THING BOILED DOWN TO A MISCOM BTWN ATC AND MYSELF, WHERE WE BOTH HEARD WHAT WE WANTED TO HEAR. I STILL AN NOT SURE, LOOKING BACK, ABOUT WHAT THE ACTUAL WORDING OF THE CLRNC AND MY READBACK WAS. THE CONDITIONS WERE NO FACTOR, IT WAS SMOOTH IMC AND THERE WERE NO DISTRS. THE STUDENT (FLYING) WAS DOING FINE.

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.