Lewiston, ID, USA
UNREG
SKYRAIDER SKYRAIDER
The private pilot, who also owned the airplane, was conducting a personal local flight. A witness at the airport observed the airplane taxi by to the east, turn west, rev up the engine as it turned around, sit for a while, and then depart. The witness reported that it was a windy, gusty day and that she did not observe anything unusual as the airplane turned to the east in a climb. She lost sight of the airplane as it went around the traffic pattern and could no longer hear the engine, and then she heard a thud. She did not hear the engine noise change, just the sudden thud. The airplane came to rest inverted in a wheat field with the tail elevated. The forward part of the airplane and the wings sustained aft crush damage and the tail was undamaged. The wreckage and ground scars were confined to the impact area. Initial examination of the engine revealed no mechanical malfunctions or failures that would have resulted in the a loss of engine power. Although an elevator control rod was found fractured, it exhibited features consistent with overstress. The wreckage was disposed of before a more thorough examination could be conducted. It is likely that the pilot did not maintain adequate airspeed and exceeded the critical angle-of-attack, which resulted in an aerodynamic stall at too low an altitude to recover.
HISTORY OF FLIGHTOn June 28, 2014, about 0922 mountain daylight time, an unregistered experimental amateur-built SkyRaider, collided with terrain near Lewiston, Idaho. The pilot/owner was operating the airplane under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. The private pilot sustained fatal injuries. The airplane sustained substantial damage during the accident sequence. The local personal flight departed Williams Airpark near Lewiston about 0900. Visual meteorological conditions prevailed, and no flight plan had been filed. A witness observed the airplane taxi by to the east; as it turned to the west, the witness heard the engine rev up. The airplane sat for a bit, and then took off. It was a windy, gusty day, and the witness didn't observe anything unusual as the airplane turned to the east in a climb. She lost sight of the airplane as it went around the traffic pattern, but could no longer hear the engine, and then she heard a thud. She didn't hear the engine sputter; she just stopped hearing anything. PERSONNEL INFORMATIONA review of Federal Aviation Administration (FAA) airman records revealed that the 29-year-old pilot held a private pilot certificate with a rating for airplane single-engine land. The pilot held a third-class medical certificate issued in April 8, 2014, with no limitations or waivers. No personal flight records were located for the pilot. The National Transportation Safety Board (NTSB) investigator-in-charge (IIC) obtained the aeronautical experience listed in this report from a review of the FAA airmen medical records on file in the Airman and Medical Records Center located in Oklahoma City, Oklahoma. The pilot reported on his medical application that he had a total time of 50 hours with 5 hours logged in the previous 6 months. AIRCRAFT INFORMATIONThe single-seat, high-wing airplane had fixed conventional (tailwheel) landing gear. It was not registered, and did not have a serial number. Maintenance logbooks were not located for the airframe, engine, or propeller. According to a former SkyRaider dealer who helped recover the wreckage, early SkyRaiders had serial numbers, and the only engine installed was a Rotax 277 model. He did not see a serial number on this airframe, and observed that the engine on this airplane was a 503 Rotax. He also thought that the tubing on the accident airframe appeared to be much lighter than the typical SkyRaider tubing. AIRPORT INFORMATIONThe single-seat, high-wing airplane had fixed conventional (tailwheel) landing gear. It was not registered, and did not have a serial number. Maintenance logbooks were not located for the airframe, engine, or propeller. According to a former SkyRaider dealer who helped recover the wreckage, early SkyRaiders had serial numbers, and the only engine installed was a Rotax 277 model. He did not see a serial number on this airframe, and observed that the engine on this airplane was a 503 Rotax. He also thought that the tubing on the accident airframe appeared to be much lighter than the typical SkyRaider tubing. WRECKAGE AND IMPACT INFORMATIONNeither the NTSB nor the FAA traveled to the site. The Nez Perce County Coroner's report noted that the airplane came to rest inverted in a wheat field, but with the tail elevated. Pictures that were provided noted no damaged crops or ground scars leading to the wreckage. The forward part of the airplane and the wings sustained aft crush damage; the tail did not contact the ground, and therefore was not damaged. ADDITIONAL INFORMATIONThe FAA inspector provided pictures to and interviewed a person familiar with SkyRaiders. The contact identified the make and model as an early Model 1 SkyRaider with a straight tail and a small, square elevator. He had observed several accidents before, and opined that since only one propeller blade sheared off, the engine may have been at a slow idle or stopped. MEDICAL AND PATHOLOGICAL INFORMATIONThe Nez Perce County Coroner determined that the cause of death was severe head trauma. An autopsy and toxicological testing was not performed. TESTS AND RESEARCHAn inspector from the FAA examined the wreckage. The engine crankshaft turned, and he observed fuel in the airplane. The propeller was a Powerfin model. One propeller blade separated near the hub; the splintered fracture surface was jagged and angular. The other blade remained attached, and split along the inboard portion of its trailing edge. The flight controls were connected at the control surfaces. The FAA inspector observed a separated elevator control rod end. The NTSB Office of Research and Engineering Materials Laboratory examined the fractured rod end and its associated tubing, and a factual report is in the public docket for this accident. The docket is accessible via a link on the ntsb.gov home page. The fracture occurred in the threaded section, which was welded into the end of the tube. The portions of the threaded section that remained attached to the rod end and the tube end both exhibited plastic deformation and fracture features consistent with overstress. No other features of a pre-existing crack or corrosion were observed. The wreckage was disposed of before further examination of the engine could occur.
The pilot's failure to maintain an adequate airspeed and his exceedance of the airplane's critical angle-of-attack, which resulted in an aerodynamic stall at too low an altitude to recover.
Source: NTSB Aviation Accident Database
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