A valve in the auxiliary power unit had suffered a complete failure, spreading fire to the tailplane, causing a loss of pitch control.

Nine minutes after that, several eyewitnesses saw large pieces of the tailplane break away from the aircraft with flames and smoke coming out from the fuselage, as the flight proceeded south from Mansfield, Pennsylvania.

[2] The aircraft subsequently lost control and plunged into a heavily wooded area served only by dirt roads.

Thereafter, the air traffic controller at New York Center vectored a Piper Aztec over the area of Flight 40's target disappearance.

Some of the witnesses were workmen at a coal strip mine who immediately took a bulldozer and plowed two roads through to the site a mile and a half away.

In a telegram to J. Edgar Hoover, director of the F.B.I., Mr. Peach wrote: "Evidence has developed in the course of notification of next of kin of crash victims which leads to strong suggestion of sabotage.