Accident Overview
On May 24, 2016, at approximately 1010 central daylight time, a Piper PA-18-150, registration N4234Z, was substantially damaged when it impacted terrain near Cozad, Nebraska. The pilot, who was the registered owner and operator of the aircraft, sustained minor injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 137 as an agricultural application operation. Visual meteorological conditions prevailed, and no flight plan had been filed.
Flight History
The flight originated from Fiese Airstrip (2NE5) in Gothenburg, Nebraska, about 1000. According to the pilot, he had just finished purging the spray booms of air and rinsate and was flying approximately 25 feet above the ground when the airplane suddenly made an uncommanded descent. The right wing struck the flat wheat field, and the airplane skidded to a stop, coming to rest inverted about 120 feet from the initial point of impact.
Aircraft Damage
The accident resulted in substantial damage to both wings, wing struts, fuselage, and tail surfaces.
Post-Accident Examination
The airplane had recently been rebuilt, and the pilot noted multiple discrepancies following delivery. One specific discrepancy was that the jackscrew and drive pulley assembly for the horizontal stabilizer were not replaced as the pilot had requested. The pilot observed that the jackscrew assembly was worn and that there was excessive slack in the drive cable, requiring constant pitch trim adjustments. The builder had informed the pilot that the assembly had been "tightened up," but the pilot stated this was not possible because the screw was made of steel and the housing was made of aluminum.
The Federal Aviation Administration (FAA) conducted an examination of the airplane after the accident. They noted play in the jackscrew assembly but determined that the slack was insufficient to cause the screw to slip. No other mechanical issues were found.