**The case that Cooper did not survive:**
The jump conditions were extremely hazardous. He jumped at night, in early winter, into mountainous Pacific Northwest terrain. He was wearing a business suit and loafers—not cold-weather gear, not boots. The temperature at altitude was well below freezing. He had no navigation equipment, no survival gear, and was presumably carrying a heavy bag of money.
The parachute situation introduced another risk factor. He did not open and examine his chutes before jumping; the evidence suggests he sorted through them and took one, but under time pressure and in a moving aircraft. Professional parachutists emphasize the importance of knowing your equipment and conducting proper pre-jump checks; Cooper’s circumstances made this impractical.
The terrain into which he was most likely jumping—dense forest, river valleys, steep ridges—is not friendly to parachute landings even in daylight with full equipment. At night, with no knowledge of what was below him, the chance of a seriously injurious landing was substantial.
The extensive 1971 search produced nothing, which is consistent with Cooper having died in an area that was searched but yielded no traces—which is plausible given the terrain and the passage of weeks before the search was complete.
The money has not appeared in any circulation in fifty-plus years. If Cooper survived and needed to live, eventually he would likely have spent some of the money in contexts where it would have been detected.
FBI investigators, at various points in the case’s history, have expressed the view that survival was unlikely given the conditions. This is not an official finding, but it reflects the professional assessment of people who have studied the case in depth.