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File / coyne-1973

The Coyne Helicopter Incident

An Army Reserve UH-1 crew and an unexplained climb

UnresolvedMilitaryVisualMultiple witnessesInstrumented
Date18 October 1973
LocationNear Mansfield, Ohio
CountryUnited States
WitnessesFour-man helicopter crew; ground witnesses in a car
Durationabout 5 minutes
Coordinates40.76° N · 82.52° W

The crew of a military UH-1 reported an approaching object, against which the captain executed a sharp descent. Afterwards the altimeter indicated a climb of several hundred metres, although the collective remained set to descend.

Official position

Blue Book had already been terminated; the case had no federal resolution.

Alternative hypotheses

  • An Orionid bolide combined with an altimeter misreading.
  • An updraft plus spatial disorientation after a violent manoeuvre.
  • A genuine object interacting with the helicopter.

What sets this case apart

Not the sighting, but an instrument reading inconsistent with control input. It is one of very few cases in the corpus reporting a conflict between what the pilot did and what the instrument showed.

At the same time: no recorder data survives. We have a reading remembered and reported by the crew, not a machine record. Four independent accounts is a great deal — but they remain accounts.


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