CHI02FA292 · Piper PA-24-260

The airplane was destroyed when it impacted the terrain during takeoff climb from runway 18. Witnesses reported seeing the airplane bank left after raising its landing gear about 100-150 feet agl. One witness reported hearing the engine overspeed after the landing gear were raised, but that the overspeed was momentary. Another witness observed the airplane in a very steep bank, approximately 80 degrees. He reported the angle of bank was reduced to about 30 degrees prior to ground impact. The passenger who was in the right rear seat of the accident airplane reported that during take-off the engine started "missing." He reported the pilot stated, "This isn't right," and reached to adjust something and soon after the engine smoothed out. The pilot made a radio call (which the witness could not hear) and banked the airplane to the left. He reported the nose and left wing dropped and the airplane's left wing impacted the ground with about a 30 degree angle of bank. The nose of the airplane hit the ground and the airplane spun around, but did not cartwheel, before it came to a stop. The witness reported that he thought the airplane's engine was no longer missing, but was operating normally when the airplane impacted the ground. The airplane wreckage was located in a harvested cornfield about 600 feet east of runway 18. The approximately 65 foot wreckage path was on a heading of about 030 degrees magnetic. A propeller slash was unearthed about 30 feet from the initial point of impact along the wreckage path. The propeller slash was about 51 inches in length measured at ground level, and it measured about 18 inches deep from ground level to the bottom of the slash mark. The north side of the ground slash had been polished smooth and exhibited a gray color on the slash's surface similar to the paint found on the propeller blades. Inspection of the flight controls revealed continuity between all flight controls and their respective control surfaces. Inspection of the engine revealed it rotated and had thumb compression and suction on all cylinders. The propeller blades had rotational scoring of the paint on camber side of the blades, but no twisting or deformation of the tips. The propeller governor's pressure relief valve spring was found broken as a result of a fatigue fracture. A functional test of the propeller governor revealed that the pressure relief setting and the pump capacity were well below specified minimums. Hartzell Propellers reported, "Such deficiency might cause a propeller to operate at reduced blade angle and higher than normal RPM after take-off." Replacement of the pressure relief valve spring at overhaul was required by Service Bulletin 176 dated November 15, 1991, was not performed. The terrain south of runway 18 at IKV was an open field with few obstacles.

Verbatim NTSB analysis and probable cause from the NTSB dataset