Sundance Airpark Airport
Aircraft Accident/Incident Report

Yukon, Oklahoma 73099
Thursday, June 30, 2011 13:50 CDT

Before flight, the commercially-rated pilot reported to a line service technician that he had been a passenger in the airplane on a previous flight, but he was now going to fly the airplane for the first time. A witness at the departure airport reported hearing a rough running engine as the airplane took off. About 5 minutes later, the airplane entered the traffic pattern at another airport. Witnesses at the arrival airport reported hearing a rough running engine as the airplane entered the traffic pattern. They observed the airplane turn left from the base leg to final approach for the runway. As the airplane turned to align with the extended runway centerline, its bank angle increased to near 90 degrees. This steep turn was likely performed by the pilot to correct for overshooting the runway’s extended centerline. The nose of the airplane dropped, and the airplane rapidly descended and impacted terrain. Signatures at the accident site and statements from the witnesses were consistent with an aerodynamic stall. Although the pilot had about 9,500 hours of experience, this was his first flight piloting this airplane, thus he likely was not familiar with it's handling characteristics. Therefore, it is likely that the pilot overshot the centerline due to his lack of experience in the airplane and the distraction of the rough running engine. In a 2012 safety study on "The Safety of Experimental Amateur-Built Aircraft," the NTSB concluded that "purchasers of used [experimental amateur-built] (E-AB)aircraft face particular challenges in transitioning to the unfamiliar E-AB aircraft. Like builders of new E-AB aircraft, they must learn to manage the unique handling characteristics of their aircraft and learn the systems, structure, and equipment, but without the firsthand knowledge afforded to the builder." Thus, the NTSB recommended that the Federal Aviation Administration and the Experimental Aircraft Association "complete planned action to create a coalition of kit manufacturers, type clubs, and pilot and owner groups and (1) develop transition training resources and (2) identify and apply incentives to encourage both builders of experimental amateur-built aircraft and purchasers of used experimental amateur-built aircraft to complete the training that is developed." A postaccident examination of the airframe did not detect any anomalies. An examination of the engine revealed that the fuel servo exceeded all of the manufacturer’s recommended maximum flowmeter limits, which would have resulted in a rich mixture. However, it could not be determined whether the discrepancy with the fuel servo was significant enough to result in a rough running engine. No other anomalies were detected with the engine.

The pilot's use of an excessive bank angle while in the airport traffic pattern, which resulted in an accelerated stall. Contributing to the accident were the pilot’s lack of experience in the airplane and the pilot’s distracted attention to the rough running engine.