NTSB Identification: SEA99FA113.
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Accident occurred Saturday, July 10, 1999 in LAFAYETTE, OR
Probable Cause Approval Date: 11/30/2000
Aircraft: Alexander VAN'S RV-8, registration: N41VA
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
While en route during an unknown phase of operation, the O-360-A1A engine, which had been overhauled by a facility in Canada and converted with 'high compression' pistons/cylinders, developed a partial power loss after about 35 hours of total operation. Metallurgical examination revealed that the #2 connecting rod fractured in two places due to fatigue at the rod end resulting in release of the rod from the crankshaft. No evidence of engine disassembly or maintenance by the owner/builder was found. Post-crash examination revealed holes in the upper engine case and disintegration of the #1 piston. A witness reported observing the aircraft at low altitude over gently rolling terrain trailing black smoke during which the pilot was observed to exit the aircraft. The aircraft rolled into a descending right turn and impacted the terrain 600 feet from the pilot's ground impact, and a post-crash explosion and fired ensued. Reconstruction of portions of the aircraft revealed sooting and evidence of pre-impact fire forward of the firewall in the vicinity of the gascolator as well as pre-impact heat damage to the Plexiglas windscreen and canopy. The only evidence of heat/fire distress observed during post-mortem was the pilot's eyebrows and forward hairline. The aircraft's canopy is airfoil shaped and during flight conditions would tend to create an aerodynamic low pressure condition near the top of the canopy. If the canopy were opened in flight with fire conditions existing along its forward exterior surface, the entrainment of hot air and fire within the upper cockpit interior environment may have become intolerable for the pilot.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: Fatigue of the number two connecting rod end resulting in a fracture at the rod end and release from the crankshaft, an ensuing in-flight fuel fed fire, followed by the pilot's abandoning the aircraft in flight. A contributing factor was pressure on the pilot induced by the conditions/events (in-flight fire entering the upper cockpit). Full narrative available
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