Narrative:

This aircraft, RV4-200, with lycoming I0-360a1b6, was being test flown after engine rebuild and new propeller and propeller governor installation. This engine is experimental in nature as it utilizes higher compression pistons, cold air induction, and 4 into 1 exhaust, to name a few. Also installed was a new whirlwind 150 series propeller with matching jihostroj propeller governor. All ground runs were satisfactory, and initially the test flight was uneventful. After the 3RD or 4TH racetrack pattern was flown around my home airport (M01), I decided to continue the flight northeast of the field. However, just after making the radio call on CTAF that I was departing the pattern, the propeller governor apparently failed, and a subsequent propeller overspd immediately followed. I had been flying at 1500 ft AGL to have altitude to make it back to the airport and to stay below mem class B airspace, and was flying with wide open throttle, and the propeller lever full forward (maximum RPM). With no warning, the RPM rose rapidly, and throttle movements had little or no effect. The only option was to load the airplane up (while slowing down) by pulling into a climbing turn. As I came through 1800 ft AGL (into mem class B), I was able to control the overspd at 3200 RPM and slowly descended back to the airport uneventfully. I never spoke with ZME on the radio, or when on the ground. My thoughts were only of returning the aircraft back to the ground safely. And once on the ground, it was discovered that one of the propeller blades had loosened itself from the hub as a result of the overspd.

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Original NASA ASRS Text

Title: RV4 PLT CLBS INTO MEM CLASS B AIRSPACE WHILE ATTEMPTING TO CTL A PROP OVERSPD.

Narrative: THIS ACFT, RV4-200, WITH LYCOMING I0-360A1B6, WAS BEING TEST FLOWN AFTER ENG REBUILD AND NEW PROP AND PROP GOVERNOR INSTALLATION. THIS ENG IS EXPERIMENTAL IN NATURE AS IT UTILIZES HIGHER COMPRESSION PISTONS, COLD AIR INDUCTION, AND 4 INTO 1 EXHAUST, TO NAME A FEW. ALSO INSTALLED WAS A NEW WHIRLWIND 150 SERIES PROP WITH MATCHING JIHOSTROJ PROP GOVERNOR. ALL GND RUNS WERE SATISFACTORY, AND INITIALLY THE TEST FLT WAS UNEVENTFUL. AFTER THE 3RD OR 4TH RACETRACK PATTERN WAS FLOWN AROUND MY HOME ARPT (M01), I DECIDED TO CONTINUE THE FLT NE OF THE FIELD. HOWEVER, JUST AFTER MAKING THE RADIO CALL ON CTAF THAT I WAS DEPARTING THE PATTERN, THE PROP GOVERNOR APPARENTLY FAILED, AND A SUBSEQUENT PROP OVERSPD IMMEDIATELY FOLLOWED. I HAD BEEN FLYING AT 1500 FT AGL TO HAVE ALT TO MAKE IT BACK TO THE ARPT AND TO STAY BELOW MEM CLASS B AIRSPACE, AND WAS FLYING WITH WIDE OPEN THROTTLE, AND THE PROP LEVER FULL FORWARD (MAX RPM). WITH NO WARNING, THE RPM ROSE RAPIDLY, AND THROTTLE MOVEMENTS HAD LITTLE OR NO EFFECT. THE ONLY OPTION WAS TO LOAD THE AIRPLANE UP (WHILE SLOWING DOWN) BY PULLING INTO A CLBING TURN. AS I CAME THROUGH 1800 FT AGL (INTO MEM CLASS B), I WAS ABLE TO CTL THE OVERSPD AT 3200 RPM AND SLOWLY DSNDED BACK TO THE ARPT UNEVENTFULLY. I NEVER SPOKE WITH ZME ON THE RADIO, OR WHEN ON THE GND. MY THOUGHTS WERE ONLY OF RETURNING THE ACFT BACK TO THE GND SAFELY. AND ONCE ON THE GND, IT WAS DISCOVERED THAT ONE OF THE PROP BLADES HAD LOOSENED ITSELF FROM THE HUB AS A RESULT OF THE OVERSPD.

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.