Primary finding
Probable cause
failure to replace an old and abraded oil feedline hose which led to its rupture and the in-flight loss of engine oil pressure. A related factor was the pilot's misjudgment of distance-to-go versus altitude remaining during the subsequent forced landing.
Investigator assessment
Analysis narrative
The engine developed an oil leak resulting in smoke in the cockpit and decaying oil pressure. The private pilot shut off the engine and attempted to land on a local desert airstrip. The airplane landed approximately 50 feet short of the airstrip and contacted several large bushes during the landing rollout. The postaccident investigation disclosed that the oil supply hose from the oil cooler to the engine had ruptured. The hose appeared to be old and heat deteriorated, but was not replaced in conjunction with a recent engine change.
Source record
Factual narrative
On May 18, 1997, at 0640 hours mountain standard time, a Navion NA-1, N8551H, was substantially damaged during an attempted emergency landing near Morristown, Arizona. The solo private pilot was not injured. The flight departed Wickenburg, Arizona, airport, at 0600 on a local, personal flight. The engine suddenly lost oil pressure followed by smoke in the cockpit. The private pilot shut off the engine and attempted to land on a local desert airstrip. The airplane landed approximately 50 feet short of the airstrip and collided with several large bushes during the landing rollout. Visual meteorological conditions prevailed for the personal flight and no flight plan was filed. A subsequent investigation by the Scottsdale, Arizona, Flight Standards District Office revealed that the oil feedline hose from the oil cooler to the engine had failed resulting in loss of engine oil pressure and the deposit of oil spray on the exterior of the engine. The pilot stated to the Federal Aviation Administration inspector that a new engine had recently been installed, however, the old oil feedline hoses had not been replaced. -