Narrative:

My aircraft was in the #1 position for the departure runway at waterloo, ia, on nov/thu/91, mid afternoon, on an IFR flight plan for osu airport at columbus, oh. I had requested FL190. The primary radar for approach/departure control at waterloo was OTS and chicago center was handling all their inbound/outbound load. Upon contacting departure control on 118.9 MHZ, I was immediately cleared to FL190. There was much radio traffic, with interruptions and 'walkovers.' as I was passing about 8000 ft, center told us to maintain 11000 ft. I reported level at 11000, and center called out our traffic at 11 O'clock, 3 mi, swbound at 12000 ft. I said that I had the traffic and heard some partially blocked exchange that told me that the other aircraft, which was a large corporate type, had me in sight too. Then center told me that after passing the traffic, I could continue my climb to FL190. I did hear the word 'climb' and words 'after passing.' I did not hear the word 'expect.' after passing, with the other aircraft at 3 O'clock high, I called out of 11000 for FL190. By this time, the other aircraft was out of my right view and about 2 mi west. Center immediately questioned my altitude, and I responded out of 11000. Center again questioned my altitude, and said I was to maintain 11000. I was able to stop the climb at 11600 and told center I had understood I was cleared to continue to climb to 190 after passing traffic.

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Original NASA ASRS Text

Title: GA SMT ALTDEV EXCURSION FROM CLRNC ALT.

Narrative: MY ACFT WAS IN THE #1 POS FOR THE DEP RWY AT WATERLOO, IA, ON NOV/THU/91, MID AFTERNOON, ON AN IFR FLT PLAN FOR OSU ARPT AT COLUMBUS, OH. I HAD REQUESTED FL190. THE PRIMARY RADAR FOR APCH/DEP CTL AT WATERLOO WAS OTS AND CHICAGO CENTER WAS HANDLING ALL THEIR INBOUND/OUTBOUND LOAD. UPON CONTACTING DEP CTL ON 118.9 MHZ, I WAS IMMEDIATELY CLRED TO FL190. THERE WAS MUCH RADIO TFC, WITH INTERRUPTIONS AND 'WALKOVERS.' AS I WAS PASSING ABOUT 8000 FT, CENTER TOLD US TO MAINTAIN 11000 FT. I RPTED LEVEL AT 11000, AND CENTER CALLED OUT OUR TFC AT 11 O'CLOCK, 3 MI, SWBOUND AT 12000 FT. I SAID THAT I HAD THE TFC AND HEARD SOME PARTIALLY BLOCKED EXCHANGE THAT TOLD ME THAT THE OTHER ACFT, WHICH WAS A LARGE CORPORATE TYPE, HAD ME IN SIGHT TOO. THEN CENTER TOLD ME THAT AFTER PASSING THE TFC, I COULD CONTINUE MY CLB TO FL190. I DID HEAR THE WORD 'CLB' AND WORDS 'AFTER PASSING.' I DID NOT HEAR THE WORD 'EXPECT.' AFTER PASSING, WITH THE OTHER ACFT AT 3 O'CLOCK HIGH, I CALLED OUT OF 11000 FOR FL190. BY THIS TIME, THE OTHER ACFT WAS OUT OF MY R VIEW AND ABOUT 2 MI W. CENTER IMMEDIATELY QUESTIONED MY ALT, AND I RESPONDED OUT OF 11000. CENTER AGAIN QUESTIONED MY ALT, AND SAID I WAS TO MAINTAIN 11000. I WAS ABLE TO STOP THE CLB AT 11600 AND TOLD CENTER I HAD UNDERSTOOD I WAS CLRED TO CONTINUE TO CLB TO 190 AFTER PASSING TFC.

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.