He jumped over Southwestern Washington, not Oregon.

The exact timing is unknown, but the area around Woodland, WA is widely held to be where he went for it. The placard that instructs one how to lower the rear stairs of the 727 Cooper hijacked was found in the vicinity.

It is known that he was no longer aboard when the plane approached PDX.

The case is open and the investigation is rich with crackpots and conspiracy theorists, but the salient facts are easy enough to find.

Come on, Mercury. This is a Northwest Legend. You can do better!