The Case Of The Three Baffled Engineers
 Blue Book Unidentified
 Oct. 15, 1953, 10:10 A. M.
 Minneapolis, Minn.

Dr. J. Allen Hynek:
Three witnesses, all research engineers employed by General Mills Aeronautical Laboratories.  A report of the Air Intelligence Service Squadron, Flight 2A, follows: 

The sighting described below took place during the theodolite tracking of a 79-ft. balloon floating at approximately 80,000 feet, on Project 85021-Grab Bag.  No sound was detected at any time during the observation. 

The object was first observed as it passed below the sun at an elevation (solar elevation) of approximately 25 degs, heading southward in horizontal flight.  It was detected by a smoke or vapor trail which extended some distance behind it, but which did not persist or form a cloud.  The object itself was not visible even through the theodolite during the first part of the sighting.  During the horizontal part of its trajectory, the object moved across the sky at a rate of 10 degrees in 9 seconds.  With an estimated altitude of 40,000 ft. this represents 15 miles per minute or 900 miles per hour.   (All three men agreed that object could have been as high as 60,000 feet, which would give a speed of 1,200 miles per hour.) 

After about 10 seconds of horizontal flight, the object appeared to go into a vertical dive.  The possibility that the appearance of a dive was produced by the object merely receding into the distance seems unlikely since the speed normal to the line of sight was undiminished in the dive.  The dive lasted for from 10 to 15 seconds,  at the end of which time the object was visible two or three times as it appeared to glow or reflect the light of the sun for perhaps a second at a time.  Just at this time the vapor trail ceased, and for a second or two thereafter the object, its outlines still unrecognizable, was seen through the theodolite not as a glare (reflected?) light, but as a gray mass in the act of leveling off.  Its size in the theodolite field was of the same magnitude as the 79-foot balloon, which means that, since it was nearer,, it would not be as large [linearly). 

The observers believe that the object was most likely a jet aircraft, but several features were unusual: 
   1. The speed was higher than normally observed; 
   2. The vertical dive was a highly dangerous if not suicidal maneuver; 
   3. A jet aircraft in such a dive would be heard for miles and would certainly cause a noticeable shock wave detectable in the area beneath it; 
   4. Vapor trails do not ordinarily occur during vertical motion though smoke trails could, of course. 

It was thought that the Air Defense Command would be interested in what was seen if. 
   a. They had no aircraft in the vicinity which could account for it; 
   b. They had no aircraft accident which might be partly explained by this report. 

Well, even Blue Book evaluated this as “unidentified.”  Perhaps the suicidal dive was too much for them. 

Dr. J. Allen Hynek
The Hynek UFO Report, page 113

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