20130428010029A

Aircraft departed chapin field airport, NY (1B2) for local flight to the south. On return leg at approximately 1000 to 1500 feet AGL the pilot (sole occupant) stated that the aircraft entered a slow shallow, uncommanded left turn which he could not stop. He reduced power and looked for a place to land. Non pilot witness statements are concurrent with the pilots statement which described the aircraft in a ?flat turn? And in ?a large circular motion? ?appeared to be flying sideways?. Pilot stated engine was operating normal and witnesses did not hear any abnormal engine sounds.

Just prior to touch down at an unknown altitude the aircraft appeared to stall and impacted in a nose down near vertical attitude. The pilot has no recollection of this part of the accident. The impact was in brushy area next to a several homes and a golf course.

The aircraft position was slightly yawed to the left if viewed in relation to level ground in a nose down near vertical position with the right wing exhibited impact damage on the outboard half of the leading edge. The left wing showed no impact damage.

The engine and propeller were displaced slightly upward and to the left of centerline.

Engine and prop could not be accessed at the site.

The pilot was taken to a local hospital and released two days later, his injures considered minor. The pilot was secured with full shoulder harness and seat belts installed in this aircraft.

The left wing was detached from the fuselage at the rear spar attach point and bent forward, the main spar attach fitting was intact. The main spar (wooden) was damaged at the attach point due to the forward twisting of the wing at impact due to the aft attach point allowing the wing to pivot forward at the, main attach point during impact.

One aileron cable turnbuckle was found detached at the left wing with the clevis bolt, nut and safety intact. It had pulled out of it?s attach point in the overhead carry through area which appears to have failed on impact due to the wing movement described above.

This was the only flight control continuity issue found during the on-site investigation.

During the inspection of the left rear wing attach fittings, no attaching hardware could be found at the crash site. The rear attach fitting on the rear spar showed no evidence of failure around the bolt hole with slight deformation of the side plates and cracking of the welds in this area. This fitting is a fork shape and the damage is consistant with a

Forward /aft movement if not secure. The fuselage attach point did not show evidence of bolt hole failure, this fitting is part of the welded steel tube airframe and is a square steel tube reinforced inside with a round tube all welded construction. Both of these fittings showed rust inside the bolt hole area. Further inspection of the fuselage area above the left rear attach point showed significant fabric and wooden stringer damage which because of its location not believed to be impact damage. It is suspect that this damaged was caused by the left wing aft spar attach fitting hitting the fuselage after becoming detached in flight and this appears to be concurrent with the pilots and witness observations.

The aircraft was removed to a secure storage facility for further evaluation at a later date.

A review of the aircraft maintenance records indicated the last maintenance documented was an annual inspection on September 5, 2012.

The aircraft accumulated 18 hours since the annual inspection. A statement within the annual inspection maintenance inspection entry indicted that all attach fittings were inspected.