N4412X

On October 15, 1997, approximately 1416 mountain daylight time, a Sego Tool Hawk H2X gyroplane, N4412X, was substantially damaged when it impacted the ground during initial climb following takeoff near Tooele, Utah. The airline transport rated pilot, the sole occupant in the gyroplane, was not injured. The gyroplane was being operated by Geoen Brothers Aviation, Inc., under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local test flight that was originating at the time of the accident. No flight plan had been filed.

According to the pilot, he was taking off for one of a series of flight tests. He reported that shortly after liftoff, the gyroplane made an uncommanded roll to the right. The pilot said that he applied full left cyclic and full left rudder, but the main rotor system struck the ground. The main rotor blades separated from the gyroplane and the aircraft came to rest with the fuselage twisted.

Postcrash examination of the gyroplane by the design/manufacturing team revealed that the control system design of this aircraft had an inherent lag in time between control input and aircraft response. They found the runway that the gyroplane was taking off from slopped 1.7 to 1.8 degrees to the left. They said that "the moment the aircraft left the ground, gravity moved the fuselage to the left and the rotor disk to the right." Subsequently, a right turn was initiated and ground contact was made by the main rotor disk before the pilot's correction inputs could take effect.