What do people think about this idea:
Cooper definitely went down the airstairs twice.
So any jump site predicted on detection of a single down/up transition of the airstairs, is wrong.
In fact, if the first transition was the detected one, than the jump would be some minimum amount of time after the first transition (due to up/down travel time on the stairs)
This assumes that the overall speed of the up transition didn't change that much, when comparing a jump off the stairs, versus walking back up the stairs. That assumption may not be true. In any case, even if it varied, the detectable oscillation/pressure bump that results, may not vary linearly with the airstair up transition velocity.
Why did Cooper have to go down the airstairs twice?
He had to use one hand to hold the rail. The overall situation would be too windy/crazy to walk down no hands.
And the stairs don't lower fully unless weighted when in flight. (air pressure) And the plane isn't going too fast (Didn't they slow down a bit when they thought Cooper was having trouble? Forget)
He had a back rig on, the money bag tied on. The reserve may have been clipped onto him somehow, but unlikely since no D rings and no easy place for the hooks on the reserve to clip onto. The closest thing would be clipping them on the webbing straps of the back rig, but that would have been difficult given the dimensions of the snap hooks on the reserve.
So assume the taken reserve was loose.
It's unlikely he threw the reserve out from the top of the stairs. The wind would have been too random to guarantee that the reserve woud go out cleanly. The stair tunnel is pretty long. And the stairs would be pushed up closed (mostly) until weighted. The post-hijack test flights show this..the stairs are pushed closed unless weighted.
Especially if Cooper had jump experience, he would want a clean exit for the stuff he's throwing out.
So he walks down the stairs (maybe not all the way) with briefcase in one hand, one hand on rail. Throws out briefcase. Goes up to top of stairs and gets reserve..goes down and throws that out.
At this point he may jump, or he may go back up and wait and go down a third time.
But I think it's most likely that airstairs transitioned down and up at least twice.
It doesn't make sense to me that the airstairs transitioned down and up just once, which is what all the DZ calculation and correlation to perceived oscillation/pressure bump depends on.
Now why didn't the pilots notice two oscillations? Well if they were just thinking of Cooper exiting, they would be attuned to a single event. Not two events.