At about 3:15 Mantell radioed that the object was “directly ahead of me and slightly above, and is now moving at about my speed or better. I am trying to close in for a better look.” He did not call again. Less than an hour later searchers found the crashed plane. Mantell was dead. His shattered watch had stopped at 3:18.
During the period of search, ground observers at Godman Field had been able to watch the UFO, gradually diminishing in size, and about 3:50 it disappeared from view. Within a few minutes, however, observers farther south in Kentucky and Tennessee were reporting an unknown object in the sky.
A hundred rumors sprang up immediately after the tragedy: that the UFO was a Russian missile; was a weird machine from outer space that had deliberately or accidentally knocked the plane out of the air when it got too close; that Captain Mantell’s body was riddled with bullets; that the plane had completely disintegrated before striking the ground; that the wreckage was radioactive.
Investigators rushed in to find the cause of the fatal crash and brought confusion with them. Some facts could be quickly established. There were no bullet wounds. The plane had not burned on impact and was not radioactive. The left wing had come off while in the air and landed 100 feet from the main crash area. Parts of the plane were scattered on a line north to south within six tenths of a mile of the central wreckage. The emergency canopy lock was in place and apparently no attempt had been made to release it. The throttle was set at one fourth open, mixture control at “Idle cut-off,” and prop control at “Full increase r.p.m.”
From this evidence investigators concluded that because of lack of oxygen Mantell had lost consciousness at about 25,000 feet, while his plane continued to climb to about 30,000 feet; leveling off, it then began a gradual turn to the left because of engine torque, and went into a spiraling dive that produced a speed and a structural stress greater than the plane could stand—the plane was “red-lined” (Air Force jargon for the limit of safety) at 525 mph. Pilots who have flown the P-51 in combat conditions have agreed with this conclusion and have suggested that, as the plane fell, Mantell may have regained consciousness, realized what was happening, pulled the throttle back and tried to pull back on the control, thus producing a stress so great that the wing was torn off and the plane then fell vertically.
As an immediate result of this tragic accident, Air Force officials recommended that all pilots be briefed again on the use of oxygen and the effects of lack of oxygen. New orders were issued; that no pilot go above 12,000 feet without oxygen under any circumstances; that no aircraft be cleared for cross-country flight unless it had been serviced with oxygen; that classes in the use of oxygen start immediately for all pilots and crew members; that all aircraft be equipped with oxygen; and that all pilots carry mask, helmet, goggles, and gloves on all flights.
The cause of the crash was known. But investigators had still to solve the problem: what was the unknown object that Mantell had been chasing?
Figure 5. UFO sightings in the Mantell case. The broken line indicates the path a balloon would have followed.
An Air Force official had announced to the press that the unknown had been the planet Venus. This explanation, while not impossible, was not very probable. The position of Venus that afternoon had indeed been very close to that of the unknown object. But with a stellar magnitude of -3.4, less than half its maximum brilliance, in the daylight sky the planet would have been visible, if at all, only as an exceedingly small, bright point of light. Furthermore this answer did not fit the pattern of sightings. The accompanying map (see [Figure 5]) of the Ohio-Kentucky-Tennessee region illustrates the succession of events: