Photo from check-six.com
Dan Cooper is the name used by the man who hijacked a flight from Portland, Oregon to Seattle, Washington in November, 1971 (the press erroneously reported his name as DB Cooper and this is how the culture now knows him). It is the only unsolved hijacking in U.S. history. 1971 was a time when you could walk right up to the jetway to greet arriving friends and relatives, could skip a flight without monetary penalty, get a free meal in coach, and sit in a decently sized airline seat. You also weren't required to present identification to purchase said seat, which means that given the nefarious events that followed, Cooper was almost certainly not the hijacker's real name.
Once airborne, Cooper quietly communicating his intent to a flight attendant, backed by a brief visual inspection of his briefcase's contents, road flares wired to look like dynamite. He demanded that once the aircraft landed in Seattle he be given $200,000 (a not insignificant amount in 1971) and four parachutes. When authorities presented these after landing, Cooper allowed the passengers to deplane, leaving only the flight crew. Taking off again, he instructed that he be flown to Mexico.
He didn't plan to reach his destination. As the aircraft approached Portland's airspace to the south, he commanded the pilots to descend the aircraft to 10,000 feet and reduce its speed to just above stall. Dismissing the attendants to the front of the cabin, Cooper lowered the Boeing 727's unique rear airstair door and jumped into the night with the money strapped to him by way of two lengths of parachute cord (a completely insufficient arrangement given what he was to encounter). It was 8:14 P.M. on November 24, 1971.
Dan Cooper did not survive the jump. For one, he was an inexperienced skydiver. The four parachutes given to him consisted of two "main" chutes worn like a backpack and two "reserve" chutes designed to clip to the main's harness at the wearer's belly. The main chute he chose had a uniquely placed rip cord that was not only difficult to find on the harness but also to manipulate (the chute was the property of an experienced jumpmaster concerned with premature deployment inside the confines of an aircraft). Second, one of the two reserve chutes was marked prominently as a training chute, which meant it was used solely in the classroom. As a parachute needs to be exercised regularly to ensure its reliable operation, only a rank novice would have placed his life in the hands of such a device. This is the one he chose to use.
Cooper's survival probability was further reduced by the environment into which he jumped. While the recorded air temperature at the time was -7C/19F, the aircraft was flying through the air at 165 knots, significantly higher than the stall speed Cooper had instructed. The resulting wind chill meant that the air Cooper actually encountered was -26C/-15F in temperature. Also, the violent slipstream almost certainly separated him from his loot, evidenced by the discovery of some of his marked bills in a river bank in 1980.
The frigid temperature wasn't fatal by itself, as shown by the thousands of successful winter night jumps made by Royal Air Force aircrews during WW2. Unlike those fighting men however, Cooper jumped wearing decidedly non-winter attire. He left his aircraft wearing loafers, a suit, and a trench coat (some accounts say a windbreaker). He was not seen with gloves so that cold air combined with the slipstream likely robbed him of the fine motor skills and limb controllability required to manipulate the funky ripcord of his main chute or that of his reserve, which was filled with stiff nylon. If he somehow did deploy one of his chutes, further risk came if he landed in one of the many bodies of water dotting that part of the country. Even the most experienced parachutist would find a water landing near lethal, especially at night and if he or she were already hypothermic.
Dan Cooper didn't survive. Evidence of this is still out there (though his mortal remains have by now been scattered by wildlife and natural events). Given his choice of egress from criminal pursuit, combined with his lack of training and suitable attire, there can be little doubt that he died that November night. Only our desire to chase mysteries and, for some, prop up an underdog keeps the mystery of DB Cooper alive.