CHI04LA060 · Piper PA-46-500TP

The airplane was substantially damaged during a gear up forced landing after takeoff. The pilot reported that everything was normal during the preflight and engine run-up. The pilot reported that after being cleared for takeoff, he advanced the throttle to 1,270 pounds of torque before releasing the brakes and everything was normal. He stated that upon reaching 85 knots he rotated, achieved a positive rate of climb, and retracted the landing gear. The pilot continued, "Just after the wheels were up the engine shuddered with a very substantial loss of power. It felt like a car that was hitting on half its cylinders." He stated he brought the power back to idle and focused on getting the airplane back on the runway. The pilot reported that after the airplane touched down he "pulled the emergency fuel cutoff." The airplane traveled straight ahead, crossed a taxiway, and came to rest about 100 yards past the taxiway. The pilot then shut off the battery and exited the airplane via the rear door. The airplane had a total of 183 hours since new. The pilot reported having a propeller overspeed warning during the flight previous of the accident flight. The tach generator was replaced after this incident. The tach generator that was removed was tested and no discrepancies were found. A tear down inspection on the engine failed to reveal any malfunctions/failures which would have resulted in the loss of power. Both the primary and overspeed propeller governors were removed from the engine and tested. A visual inspection of the primary governor revealed lockwire found on the airbleed system reset-eccentric screw was non-standard for Woodward and the torque sealant had been removed. A visual inspection of the overspeed governor revealed the inside of the speed setting hex screw did not contain any torque sealant. The sealant on the outside threads of the screw was cracked near the base of the screw and the housing. Bench testing of both the primary and overspeed governors revealed the overspeed governor was set to a lower rpm than the primary governor. Therefore, the overspeed governor would have been controlling the system. Manufacturing flight test documents indicate four occasions when the maximum reverse rpm was adjusted. Flight tests conducted with the governors calibrated to the settings at the time of the accident were conducted. Data from the flight tests indicate the propeller rpm was limited between 96-97% and that changes in the rpm stabilized within seconds.

Verbatim NTSB analysis and probable cause from the NTSB dataset