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Case · C-004

Kenneth Arnold and the nine objects between Mount Rainier and Mount Adams

Mount Rainier – Mount Adams, Washington · United States · Jun 24, 1947

In flight Pilots

Disputed explanation

What happened
Shortly before 3 p.m. the private pilot Kenneth Arnold, who had set out from Chehalis and was flying near Mineral at about 2,800 meters, saw nine shining objects in a line pass Mount Rainier and then Mount Adams, and estimated their speed at over 1,200 miles per hour. His account, collected by a Pendleton (Oregon) newspaper and picked up by the wire services, gave rise to the expression “flying saucers.” The case was examined by the Army Air Forces and ended up in the Project Blue Book case files held at the National Archives; an essay by Blue Book chief Hector Quintanilla, distributed by the CIA, reports its mirage conclusion.
Proposed explanation
The public conclusion of the Army Air Forces was a mirage. Other explanations have since been proposed, none shared by all: clouds or wind-blown snow on the ridges (the astronomer Donald Menzel), mirages due to temperature inversions (Steuart Campbell), meteors (Philip Klass), flocks of pelicans (James Easton) and jet aircraft (some officers and analysts of Project Sign).
Official investigation
Army Air Forces (intelligence), then U.S. Air Force (Project Sign and Project Blue Book)
Words of the document
Scientists who reviewed Arnold's sighting concluded that the objects were a mirage.

Official documents

  1. Page from the June 24, 1947, Kenneth Arnold sighting report (NAID 28929152) · National Archives – Project Blue Book case files (U.S. Air Force) · 1947
  2. The Investigation of UFO's (Hector Quintanilla Jr.), approvato per il rilascio il 22 settembre 1993 · CIA – CIA Historical Review Program (author: the head of Project Blue Book) · Sep 22, 1993

Sources

  1. Wikipedia – Kenneth Arnold UFO sighting (other)
  2. HistoryLink, Walt Crowley – Kenneth Arnold's sighting (2003) (analysis)
  3. National Archives – the Project Blue Book documents 50 years after its closure (other)

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