AS-III N157AP accident near Poipu, Hawaii

Probable cause

The pilot's lack of compliance with manufacturer's guidance for care and handling of the aircraft combined with incomplete preflight inspections, which resulted in an undetected material failure of the nose cone.

NTSB analysis

The special light sport weight-shift control aircraft, commonly referred to as a "trike," took off from its base on the island of Kauai, Hawaii, on a "discovery" flight. On board were the instructor-rated pilot and the passenger-student. According to the pilot, while in cruise flight about 45 minutes after takeoff, the aircraft became "extremely difficult" to control, and the fabric wing skin was "fluttering intensely" along its trailing edge. The pilot opted for a precautionary landing on a nearby golf course. During the landing roll, the aircraft tipped onto one wing.

Postlanding examination of the aircraft revealed that the fabric nose cone that was installed over the centerline juncture of the two wing leading edge tubes was damaged. The purpose of the nose cone was to prevent ram air from entering and inflating the wings during flight, which would change the wing profiles and result in controllability problems. The aircraft manufacturer indicated that the nose cone damage was primarily due to the nose cone being left in place when the wings were folded for transport or storage, a practice which was strongly discouraged by the manufacturer. In addition, although the manufacturer recommended against unprotected storage of the aircraft to preclude fabric deterioration from the elements, the pilot was known to store the aircraft outside on a regular basis. In combination, those practices by the pilot, which were contrary to the manufacturer's guidance, resulted in the degradation and eventual failure of the nose cone. With the aircraft on its wheels, the nose cone and upper surface of the wing were at least 8 feet above the ground, but there was no evidence that the operator or the accident pilot had or utilized a stepladder or other means to access and inspect the nose cone and wing upper surface before flight. The lack of equipment to conduct a thorough preflight inspection prevented timely detection of the deterioration of the nose cone.

Text from the NTSB. Open the NTSB docket for WPR11LA081 for the full record.