NTSB Factual Report

On February 03, 2001, at 1400 eastern standard time, a Robert Wood, Velocity XLFG, N658SE, an experimental airplane, collided with the ground during an emergency landing near Sebastian, Florida. The personal flight was operated by the pilot under the provisions of Title 14 CFR part 91 with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The experimental airplane received substantial damage, and the commercial pilot received minor injuries. The flight originated from Sebastian, Florida, at about 1330.

According to the pilot, this was the first test flight of this experimental airplane. The pilot stated that after climbing to approximately 2000 feet and accelerating to approximately 135 knots, the left winglet began to flutter. The pilot reduced power to slow down, and applied left rudder pressure. The left rudder stopped fluttering, but then the right rudder began a severe flutter. The pilot applied right rudder pressure, but obtained no response. The aircraft then began an uncommanded right turn. The pilot began a descent and attempted an emergency landing in a field near the departure airport. Upon touchdown, the aircraft nosed over and came to rest inverted.

Examination of the airplane revealed that winglets, and attached rudders, had been installed. Reportedly, winglet rudders operate independent of each other and only moves outward to create drag, which yaws the airplane. The trailing edge of the left and right rudder is designed with a slight out ward bend, thus allowing the relative wind to apply pressure in the opposite direction of the normal movement of the rudder. Such pressure forces the rudder against its stop, or maintains pressure against the rudder cable during application of rudder control input, and, therefore prevents flutter. The trailing edge of the left and right rudders installed on the accident airplane were manufactured with a slightly inward bend, which allowed the relative wind to apply pressure in the direction of the normal movement of the rudder. The examination also disclosed that the right rudder cable attachment arm was ripped out of the right rudder attach point during flight due to excessive loads imposed by flutter. The examination also revealed that the composite material construction in the left and right wings, and bonding techniques for metal to fiber structures, were not completed in accordance with normal procedures.

NTSB Probable Cause

The manufacturer's inadequate design of the winglet/rudder assembly, and inadequate bonding techniques for metal to fiber structures, which resulted in control surface flutter.