Originally Posted by PCheng
To survive a jump from a plane travelling at up to 600 miles per hour at altitudes of 40,000 ft, you will need more than just a parachute. You will also need a military grade jump suit, oxygen mask and a ton of luck.
And that is assuming the plane is travelling straight and level. If the plane is spiraling out of control, the centrifugal force will pin you to your seat and you will black out before you can make it to the door.
And let's not forget the good men and women of TSA. I am sure they look forward to questioning you why you are trying to board the plane with parachutes on your back.
With a ton of luck you could get away without the oxygen, especially if you had an automatic activation device. There's been a military punchout at 35k where he lost his oxygen and he was only wearing a pilot's suit. He managed to keep himself conscious until he was low enough he could pull the cord. This guy had luck by the bucketfull--he was unable to blow the canopy and fired the seat through the canopy (which is how he lost his oxygen.)