Narrative:

Upon entering IMC on climb out from boeing field at approximately 300' MSL I made a series of heading changes caused by momentary vertigo. I was flying an small aircraft, which is not a stable IFR platform. It was the first time I'd flown this aircraft and suspected the heading indicator was precessing a lot. I must have reset the high to compass while compass was still in oscillation as later hi was 20-30 degrees off compass heading. I was then behind the aircraft and chasing the compass. I was given a course of 230 degrees to fly by approach, direct olm VOR. Sea approach must have noticed my oscillations as he commented, 'you must have a navigation problem, set hi to magnetic compass and fly 230 degree magnetic.' I settled down after that and continued to olm VOR and en route VMC over the cloud deck. The main factor was my not trusting the hi when it was working properly and my heading control was defective. There was no turbulence to speak of. I as a relatively inexperienced IFR pilot in a squirrely aircraft. I am now more familiar with that particular aircraft and would file IFR with reservation and only if I had to in order to land safely.

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Original NASA ASRS Text

Title: PLT OF SMA HOLDING ERRATIC HEADING ON IFR. CTLR COUNSEL ASSISTED IN HOLDING MORE STEADY HEADING.

Narrative: UPON ENTERING IMC ON CLBOUT FROM BOEING FIELD AT APPROX 300' MSL I MADE A SERIES OF HDG CHANGES CAUSED BY MOMENTARY VERTIGO. I WAS FLYING AN SMA, WHICH IS NOT A STABLE IFR PLATFORM. IT WAS THE FIRST TIME I'D FLOWN THIS ACFT AND SUSPECTED THE HDG INDICATOR WAS PRECESSING A LOT. I MUST HAVE RESET THE HIGH TO COMPASS WHILE COMPASS WAS STILL IN OSCILLATION AS LATER HI WAS 20-30 DEGS OFF COMPASS HDG. I WAS THEN BEHIND THE ACFT AND CHASING THE COMPASS. I WAS GIVEN A COURSE OF 230 DEGS TO FLY BY APCH, DIRECT OLM VOR. SEA APCH MUST HAVE NOTICED MY OSCILLATIONS AS HE COMMENTED, 'YOU MUST HAVE A NAV PROB, SET HI TO MAG COMPASS AND FLY 230 DEG MAG.' I SETTLED DOWN AFTER THAT AND CONTINUED TO OLM VOR AND ENRTE VMC OVER THE CLOUD DECK. THE MAIN FACTOR WAS MY NOT TRUSTING THE HI WHEN IT WAS WORKING PROPERLY AND MY HDG CTL WAS DEFECTIVE. THERE WAS NO TURB TO SPEAK OF. I AS A RELATIVELY INEXPERIENCED IFR PLT IN A SQUIRRELY ACFT. I AM NOW MORE FAMILIAR WITH THAT PARTICULAR ACFT AND WOULD FILE IFR WITH RESERVATION AND ONLY IF I HAD TO IN ORDER TO LAND SAFELY.

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.