N20GT - Accident Report

NTSB Identification: ANC05LA033.
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Accident occurred Saturday, February 12, 2005 in Marion, MS
Probable Cause Approval Date: 3/28/2006
Aircraft: Twente Pitts Model 12, registration: N20GT
Injuries: 2 Fatal.

The commercial certificated pilot/owner was conducting a low altitude aerobatic flight maneuver in an experimental, amateur-built airplane under Title 14, CFR Part 91 when the accident occurred. An FAA inspector who traveled to the site said a witness told him that the airplane had just completed a loop when it rolled abruptly to the left and dove into the ground. The inspector said the airplane impacted the ground in a near vertical attitude. Additional witnesses told the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), that the pilot/owner typically performed single aerobatic maneuvers at 800-1,000 feet above the ground. One witness told the IIC that she saw the airplane descending in a spiral, as she had seen before, but the spiral was tighter and faster than before. She said the pilot did not pull out at the usual height, and descended below the trees. The first person to the accident site was a student pilot and friend of the accident pilot. He said he and his wife watched the accident airplane perform a loop and then enter a counter-clockwise spin at the bottom of the loop. A postcrash fire consumed most of the airplane. During the on-site examination, the FAA inspector found the right cable attachment point to the rudder horn had fractured, and the cable was disconnected. The rudder horn assembly was sent to the NTSB Materials Laboratory for analysis. The analysis disclosed that prior to the fracture, the outboard portion of the horn, where the cable was attached, was bent downward almost perpendicular to its normal plane of rotation. Information received from the rudder horn manufacturer indicated that under normal flight control inputs, there are no mechanical loads that would account for the deformation of the rudder horn prior to the fracture. The airplane was kit-built, and maintained by the pilot under the "condition inspection" criteria. No pilot, airframe, or engine logbooks, were discovered for examination. No evidence of any preimpact mechanical anomaly was found.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

The pilot's failure to maintain control of the airplane while performing a low altitude, aerobatic maneuver, which resulted in an uncontrolled descent, and an in-flight collision with terrain. A factor associated with the accident was the initiation of a low altitude aerobatic maneuver.