There’s no evidence he was successful that I’m aware of though I have not followed it closely.
His reserve chute was sewn shut, it was a demo model. An experienced chutist would have checked that. For that matter, maybe they gave him a sabotaged main chute? He jumped at night, in a rainstorm.
None of the cash has ever been spent. Somebody found about 5k along a river in 1980, that was part of the money given to him. Theory is he landed in water and drowned. Dredging operations blew some of the money onto the bank where it was later found.
What’s weird is nobody noticed this guy disappearing in his immediate family.
That is why I said apparently successful.
I remember reading about a sum of money being found awhile back. I went looking and here is what I found:
In 1980, $5800 of the ransom money (290 bills) was found buried on a sandy shore of the Columbia River near Vancouver, Washington over twenty miles from Lake Merwin. The money was deteriorated and water logged but was still bundled in the original packing. Over $194,000 or 9700 bills from the ransom have never been recovered.
In 2008 a piece of parachute found near Amboy, Washington, six miles from Lake Merwin, is believed to be one of the two parachutes that Dan Cooper used in his escape from the hijacked airplane. These items, the money, placard and parachute are the only evidence that has ever been located in connection with the crime.
Since they have never found a corpse, it remains unclear of he perished during his escape attempt, or if he was successful. The fact that none of the remaining 194,000 has ever turned up is perplexing to say the least and would suggest that something happened to him. But there is certainly no evidence to prove that is the case.
Then, in 2011, an Oklahoma City woman, Marla Cooper, came forward to claim that her uncle, Lynn Doyle Cooper, generally known as L.D., was D.B. Cooper of the 1971 hijacking. Lynn Doyle Cooper was known to be a huge fan of the French comic book character Dan Cooper who was a skydiving hero. L.D. was an avid outdoorsman and a logger who was raised in the small town of Sisters, Oregon. He was very familiar with the northwest woods and possessed the survival skills that would be needed to get out of the area following a parachute landing. Marla Cooper believes that he lost control of the money after jumping from Flight 305 explaining why the money has never made it back into circulation.
Marla states that L.D. and another of her uncle’s left her grandmother's house on the morning of November 24th, 1971 on a turkey hunting trip but returned on the 25th bruised and bloody claiming to have been in a car crash. Shortly after that L.D. Cooper disappeared and was not seen by the family again.