Following John Denver's fatal airplane crash of Oct. 12, 1997, investigators with the National Transportation Safety Board concluded that low fuel, modifications to the aircraft and compromised access to fuel switches likely contributed to the tragedy. No drugs, alcohol or otherwise foreign substances were found in the singer's system upon autopsy.
Investigators concluded that the chief complication leading to the crash was the location of the switch allowing Denver to change fuel tanks during flight, a switch they believed he was unable to reach properly. They discovered that Denver had actually discussed the problem with an aviation technician earlier that day, and that fuel reserves in his aircraft had been significantly depleted during a test flight to Monterey.
The plane itself was an experimental model called a Rutan, the designer of which had moved the fuel selector valve from the customary location between the pilot's legs to a position behind his left shoulder. Denver reputedly attempted to bypass the problem by accessing the switch with vise-grip pliers, but this proved impossible due to the constraint of his safety straps. Investigators then determined that any pilot trying to access the switch would be required to perform a 90-degree turn with his body, a movement promoting improper rudder action and an ultimate yawing or pitching of the plane.