WPR19LA171

The pilot reported that he was practicing touch-and-go takeoffs and landings when, shortly after departure while climbing through about 400 ft above ground level in a right turn, he heard a loud bang and felt a vibration. The vibration ceased, and the pilot continued to his intended destination with no other anomalies noted. Substantial damage to the aft right fuselage was discovered during postflight inspection. Examination of the aft fuselage revealed that the fuselage skin exhibited diagonal buckling, several stringers were bent or deformed, and several bulkheads were damaged. Opposing diagonal buckles or skin fractures in an “X” pattern were noted at several locations on the fuselage skin, coincident with a stringer or bulkhead location. No obvious damage was noted to the left side of the fuselage. The damage to the airplane was consistent with an empennage flutter event; however, in the absence of additional information, the cause of the flutter event could not be determined.

On May 3, 2019, about 1130 Pacific daylight time, a Beech 35 airplane, N2839V, was substantially damaged when it was involved in an accident near Deer Park, Washington. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he was practicing touch-and-go takeoffs and landings. Shortly after departure, climbing through about 400 ft above ground level and while in a right turn, he heard a loud bang and felt a vibration. The vibration ceased and the pilot continued to his intended destination with no other anomalies noted. Federal Aviation Administration inspectors examined the airplane and confirmed there was no evidence a bird or object struck the airplane. Substantial damage was noted to the aft right fuselage between about fuselage station (FS) 200 and FS 256. The fuselage skin exhibited diagonal buckling, several stringers were bent or deformed, and at least three fuselage bulkheads were fractured or deformed. Opposing diagonal buckles or skin fractures in an “X” pattern were noted at several locations on the fuselage skin, coincident with a stringer or bulkhead location. There was no obvious damage noted to the left side of the fuselage. An NTSB structures engineer examined photos of the airplane damage and determined that it was consistent with an empennage flutter event. The airplane was not available for further examination, and maintenance records were not available for review. The accident airplane was involved in two previous empennage flutter events, which occurred in August 1996 and April 1997.