Been reading this thread and your comments about pulling the ripcord early if an inexperienced diver make complete sense. So Let me ask two questions here? I personally believe he was ABSOLUTELY EXPERIENCED based on his knowledge of the planes and chutes. His complete calmness right until his departure. So if he knew what he was doing and most of us believe he did, in 1971, with clouds below, and lets say he can trust the 10,000 feet altitude he ordered the pilots to maintain? Could he have lets say counted, like 1,2,3,4 etc to guess his altitude when he pulls? IE, would he know how many feet per second he would drop? Second question, is the movie Point Break. I assume you have seen it. The one with the late great Patrick Swayze and Keano Reeves. Not the newer remake. (which I have not seen). The parachute scene is crazy as you know. So Swayze pulls his chute very very late. Maybe hundreds of feet from the water? How far fetched is that? And the control they had before they pulled the chutes? Can we believe that DB Cooper could have had more control than people have been told? Perhaps he could have maneuvered before he pulled the cord or if he pulled on one rope would it not steer him to some degree?
DBfan - Sorry, I didn't mean to blow off your questions, sometimes I miss a few days and your post got past me. So if you're still interested, better late than never. (Although on a 50 year old case, how late can I be?) There are a lot of variables for the answers.
Was Cooper experienced? I guess no one really knows, but as you say, the fact that he seemed familiar with the parachutes would seem to indicate that he was. But what kind of experience and how much? If his experience was military, he likely had a handful of static line jumps. He would be familiar with the harness, somewhat familiar with the canopy control, but not familiar with freefall. If he was a civilian sport jumper, he would likely have many more jumps. He would be familiar with the harness and the canopy control. How familiar he would be with freefall would depend on how many jumps he had and how good he was at it. Freefall control is kind of like learning to ride a bicycle, in that there is a subtle balance point to it. It can be wobbly to learn, but once it 'clicks' it's pretty intuitive and not very hard. And like anything, some people take to it better than others.
Altitude - Yeah, I think he could count on the pilots' flying at the requested 10k'. But, pilots use altitude at MSL, which is above sea level. The useful altitude a jumper has is AGL, above ground level. The difference would be the elevation of the terrain below him. I've heard varying reports of how high the mountains were below him, some people say 2k to 3k, I think R99 said some as high as 4k to 5k. If he's smart, he would consider the highest possible terrain and use that as his workable altitude. So if the highest mountains below him might be at 5k, he would subtract that from the 10k and figure he had 5k below him to work with. Yes he could count that out in seconds. There are standard freefall tables that tell how far you would fall in how many seconds. Remember that it takes several seconds to achieve terminal velocity, so in your first seconds you don't fall as far as you would in the same time at terminal. Smart experienced jumpers also develop a decent sense of visual altitude awareness. But that would depend on several factors. How solid was the cloud cover, were there holes where he could see to the ground? What was the moon, how much ambient light? How close was he to a city or other ground based light sources. Another thing a smart jumper does when jumping in clouds is to take note of what the lowest cloud base is, whether he could count on coming out of the bottom of the clouds and have altitude left.
Point Break - All the skydiving scenes in the movie are real (except the low pull) so all the freefall control you see is real. The 'Hollywood' parts are that they edited several jumps together so that their scene lasts longer than actual jumps do, and Keanu's character, you're not going to be that good at it on your first jump.
Pulling low - It varies, but typically a sport jumper opens the parachute at around 2500'. This allows time to deal with a malfunctioned main and get under a reserve if needed, and also time to maneuver into the desired landing area. But it's not necessary. In Cooper's day it wasn't uncommon for people to pull low on purpose for 'sport'. ('Ground rush is a gas, but it sure ain't practical.') And Cooper was jumping with one parachute, and those bailout rigs ARE reserves. His kind of chute would typically open in a few hundred feet. Once it's open and flying, it neither knows nor cares whether there's 2000, 200, or even 20 feet below. It's doing what it does. I wrote a piece at dropzone a while back speculating the possibility that Cooper could have maneuvered in freefall over an open field and pulled so low so as not to drift into trees. A lot of unlikely suppositions to that, though.
Canopy control - It's generally regarded that the chute he had was an unmodified, non steerable one. Pretty much no control. Yeah, he could pull on the lines and get a bit of drift or turn out of it, but not much. However, and this is speculative, but if Cooper knew enough about chutes to be familiar with a certain modification on some reserves known as a 'four line release', and if he had access to his knife when he got under canopy, he could potentially do some in-air rigging. Once he was under the open parachute, he could cut the four rear-most lines. This would allow the bottom of the back of the chute to rise up in kind of a 'bubble' shape. This would allow some air to escape out the back, giving the chute some forward drive. Then, by pulling either the next outside lines, or just the risers, he could steer it. That would give him some control and sort of allow him to choose his landing site.
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