Narrative:

I was alleged to have been given an altimeter setting of 30.41; however I only read back and wrote down 41 in my read back sequence. The number in the colesman window left over from the last flight that was closest to something ending in .41 was 29.41. So I entered 29.41Departing hao I said 'cincinnati baron n-----; off hao leaving 900 feet for 3;000.'there was no correction of my reported altitude by ATC at that point. I was assigned to level off at 3;000 during the climb. I did level off at 3;000 feet as indicated on my altimeter however with the altimeter setting off by an entire inch meant I was really at 4;000. There was another baron in the opposite direction that 5 minutes or so prior was at 4;000 and was assigned to climb to 8;000 and at that time the other baron was given a new ATC frequency. This other baron was now on another frequency and therefore I couldn't hear anything about the separation issue and the fact that the other baron was alleged to have been given course deviation instructions. After arriving at 3;000 feet (really 4;000) my ATC frequency was pretty quiet (because the deviation instructions and the separation issue was going on; on the newly assigned frequency given to the other baron) after being at 3;000 (really 4;000) for several minutes the controller came back onto my frequency and said you just caused a separation situation that required deviation instructions; call this phone number as soon as possible.

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Original NASA ASRS Text

Title: A BE55 pilot reported receiving an altimeter setting of 30.41 prior to departure but enters 29.41 in error. On departure he leveled off 1;000 feet above the assigned altitude of 3;000 feet causing a loss of separation.

Narrative: I was alleged to have been given an altimeter setting of 30.41; however I only read back and wrote down 41 in my read back sequence. The number in the colesman window left over from the last flight that was closest to something ending in .41 was 29.41. So I entered 29.41Departing HAO I said 'Cincinnati Baron N-----; off HAO leaving 900 feet for 3;000.'There was no correction of my reported altitude by ATC at that point. I was assigned to level off at 3;000 during the climb. I did level off at 3;000 feet as indicated on my altimeter however with the altimeter setting off by an entire inch meant I was really at 4;000. There was another Baron in the opposite direction that 5 minutes or so prior was at 4;000 and was assigned to climb to 8;000 and at that time the other Baron was given a new ATC frequency. This other Baron was now on another frequency and therefore I couldn't hear anything about the separation issue and the fact that the other Baron was alleged to have been given course deviation instructions. After arriving at 3;000 feet (really 4;000) my ATC frequency was pretty quiet (because the deviation instructions and the separation issue was going on; on the newly assigned frequency given to the other Baron) After being at 3;000 (really 4;000) for several minutes the controller came back onto my frequency and said you just caused a separation situation that required deviation instructions; call this phone number as soon as possible.

Data retrieved from NASA's ASRS site 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.