Kenneth Arnold was a private pilot who, on June 24th 1947, was on his way to Yakima, Washington when he decided to make a detour. There was a $5,000 reward for anyone who could find the wreckage of a U.S. Marine Corps C-46 transport airplane that had gone down close to Mt. Rainier. He didn’t find anything and decided to continue on his business trip. He was heading east when he saw a bright flash of light. Thinking that it might have been the reflection of sunlight off a mirrored surface, he scanned the skies for any other aircraft, but could only see a DC-4 some distance behind him.

He put it out of his mind but only 30 seconds later he observed a series of bright flashes off to his left. He initially believed that it might have been reflections on the windows of his airplane, but quickly ruled that out. They came instead from a number of flying objects. Arnold rejected the idea of a flock of geese given the altitude and the speed at which they were travelling. They approached Mt. Rainier, moving erratically and giving off occasional bright flashes. Arnold estimated that they were slightly larger than a DC-4 and had a motion similar to a saucer skipping on water. Even though he hadn’t stated they were shaped as thus, the media nevertheless referred to them as ‘flying saucers’. Being a pilot himself, Arnold was more than capable of doing the necessary calculation and he estimated that they were moving at a speed of 1700 miles per hour, roughly three times faster than any known manned aircraft at the time. This led Arnold to suspect that they were some sort of new jet being tested by the Air Force.

Arnold landed in Yakima around 4:00 p.m. and proceeded to share his story with the airport’s General Manager Al Baxter, who reportedly didn’t believe him. A number of other pilots did, but they too believed that he had seen either guided missiles or a new, experimental craft. Reporters finally caught up with him the next day and were impressed by his witness statements. Arnold was a careful observer and a businessman. His description of events was filled with minute details and lacked the hysterical embellishments of other accounts. However, Arnold wasn’t very happy about his new found fame.

Thus far, Arnold had maintained that the objects were of earthly origins but a story broke on July 7th 1947 which stated that he was beginning to consider the possibility of extra-terrestrials. According to him, the speed at which they were making turns in the mountains would have been near impossible for any human pilot. Arnold bought a video camera to take with him on flights, in the hopes of capturing footage should he see the objects again. His evidence was partially corroborated by Fred Johnson, a prospector on Mt. Adams, who wrote AAF Intelligence with an account of six objects he had seen through his telescope around the same time as Arnold’s sighting. In fact, it turned out that a number of other witnesses existed.

The best corroborative sighting though came some ten days later when the crew of a United Airlines flight en route to Seattle saw between 5 to 9 disc-like objects that kept up with their plane for about 15 minutes before disappearing. Photos were also taken by Enlo Gilmore on July 12th 1947 and William Rhodes on July 7th. In the latter case, the FBI and military confiscated Rhodes’ photos, although they showed up later in Air Force intelligence reports.

The military denied having any aircraft in the area at the time although, as it was subsequently pointed out, they were hardly likely to admit they had been testing top secret aircraft. Other investigators pointed out that Arnold’s sketch of one of the objects, which he claimed looked different from the rest, bore a striking resemblance to the German Horton Ho 229. Although the military published a report stating that Arnold clearly believed what he saw was real, and that he was a man of integrity, they nonetheless determined that he had been the victim of a mirage. Other possible explanations included meteors, pelicans and even snow clouds.

In spite of this, AAF intelligence and the FBI began a secret investigation of the most reliable sightings from pilots and military personnel. After three weeks they concluded the reports were not the result of overactive imaginations nor could they be adequately explained by natural phenomena. This ultimately led to the formation of Project Sign at the end of 1947, the first publicly acknowledged UFO investigation by the Air Force. Project Sign eventually became Project Grudge, and then evolved into Project Blue Book.