The flaps in any position wouldn't have any affect on the stairs. the slower the plane, the lower the stairs could go. they would have less stress (wind load). once they started slowing down on approach the stairs began to drop until finally in taxi they were dragging.

The stuntman in the movie appears to be crouched at the bottom of the stairs at 150 knots. in the down and locked position, the stairs measure just shy of 7 feet for clearance. odds are that all of those who jumped were probably in a slight crouched position'

The railing stops before the last step. Cooper was probably on the second or third step up from the bottom..

Also, if the code was the same in 1971, the railing would be at 42" in height. when you go below that, it's hard to grab onto while go up or down. that's 3 1/2 feet.

McNally went down on his ass, feet first rolling over and allowing his body to merge off the stairs.

A total of 11 steps (treads) from the hinge point to the ground. the steps above that are fixed to the aircraft.

But, the stairs during the Cooper jump and the sled test were UNLOCKED - free to move. As the attached shows.

Unlocked stairs apparently ride in the slipstream where the sled test photo shows them riding.

When stairs are unlocked and free to move they are free to mechanically vibrate. As they move acoustic effects in the cabin changes - like a musical instrument! It is important to distinguish the two effects: mechanical vibrations of the stairs vs. Bernoulli effects in cabin pressure due to the fuselage hole changing as the stairs move. Its like a wind instrument, say a trumpet or trombone.

FJ is saying all vibrations and bumps can only happen when the stairs are at their fullest extent, due to weight being on them. That is the same as saying: a trombone can produce all of its notes ONLY when the slider bar is at its fullest extent! FJ does not understand the principle of how and why simple resonating systems work! In fact I am rather sure FJ will contradict everything I am saying because he does not know what he's saying, or the implications of what he is saying.

When the airstairs are in the unlocked position they are like a large tuning fork that vibrates in the air stream. Since the stair assembly opens and closes a hole there are also acoustic Bernoulli effects in cabin air, like pressure notes/frequencies! Mechanical Oscillations vs pressure bumps/notes! Both types of effects were noted by the crew during the sled test and during the hijacking once the airstairs were unlocked.

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The flaps in any position wouldn't have any affect on the stairs. the slower the plane, the lower the stairs could go. they would have less stress (wind load). once they started slowing down on approach the stairs began to drop until finally in taxi they were dragging.

The stuntman in the movie appears to be crouched at the bottom of the stairs at 150 knots. in the down and locked position, the stairs measure just shy of 7 feet for clearance. odds are that all of those who jumped were probably in a slight crouched position'

The railing stops before the last step. Cooper was probably on the second or third step up from the bottom..

Also, if the code was the same in 1971, the railing would be at 42" in height. when you go below that, it's hard to grab onto while go up or down. that's 3 1/2 feet.

McNally went down on his ass, feet first rolling over and allowing his body to merge off the stairs.

A total of 11 steps (treads) from the hinge point to the ground. the steps above that are fixed to the aircraft.

But, the stairs during the Cooper jump and the sled test were UNLOCKED - free to move. As the attached shows.

Unlocked stairs apparently ride in the slipstream where the sled test photo shows them riding.

When stairs are unlocked and free to move they are free to mechanically vibrate. As they move acoustic effects in the cabin changes - like a musical instrument! It is important to distinguish the two effects: mechanical vibrations of the stairs vs. Bernoulli effects in cabin pressure due to the fuselage hole changing as the stairs move. Its like a wind instrument, say a trumpet or trombone.

FJ is saying all vibrations and bumps can only happen when the stairs are at their fullest extent, due to weight being on them. That is the same as saying: a trombone can produce all of its notes ONLY when the slider bar is at its fullest extent! FJ does not understand the principle of how and why simple resonating systems work! In fact I am rather sure FJ will contradict everything I am saying because he does not know what he's saying, or the implications of what he is saying.

When the airstairs are in the unlocked position they are like a large tuning fork that vibrates in the air stream. Since the stair assembly opens and closes a hole there are also acoustic Bernoulli effects in cabin air, like pressure notes/frequencies! Mechanical Oscillations vs pressure bumps/notes! Both types of effects were noted by the crew during the sled test and during the hijacking once the airstairs were unlocked.

FlyJack has also come up with a new version of how the winds aloft are determined.  According to FJ, the winds aloft are actually "time-averaged" values, whatever that means in relation to the forecasts that the National Weather Service provides for the aviation community.

In reality, the winds aloft forecasts provided to pilots is an estimate of the winds that they can expect to encounter at specified areas and altitudes during the forecast period.

Further, the actual winds aloft measurements obtained by the NWS by means of radiosondes is the instantaneous values and has nothing to do with "time-averaged" values either.

Mark EM: Actually 727s never did operational airdrops during the war in SE Asia. The 727 airdrops over Korat Thailand were experimental ops to test the concept. There was no need to masquerade as a civilian airliner in Vietnam War ops. There were military aircraft far better suited for airdrops such as C 130, C 123 and Caribous.

Marks comment earlier today over that the DBC research Facebook group had me sleuthing to try and confirm our speculation that unmodified 727’s weren’t used operationally for covert ops during the war. Mark mentioned this to me a couple years back at cooper con and it made sense but I wanted to see if I can get confirmation. I just spoke with a former president of Souther Air Transport William “Bill” Langton and he gave me some great info that I’d like to share with the group. He informed me that Souther Air Transport did in fact have one single 727 that they used for covert opps. SAT actually took delivery of the first ever combi 727 off the line. He told me the covert part was flying over china and dropping agents who would then walk out. He told me there were no controls in the cockpit to lower and retract the stairs. All the controls were in the aft stair well. I know there were some files/reports albeit conflicting with others...saying that cooper thought the stairs could be controlled from the cockpit and many have speculated that maybe the Air America/SAT combi versions had cockpit controls and that’s maybe why he said it. I think we can dispel that now. The most interesting and key piece of information I gathered speaking with Bill was during the covert opps they were able to retract the stairs in flight before they landed. I’ve theorized that cooper could of retracted the stairs in flight and with the slipstream it would of slammed the the stairs back into the fusel creating a similar action as the stairs springing back up from jumping on them. Most experts on the case have told me that would be inpossible but now we its been done! This puts  the fbi dropzone into bigger question for me now. If cooper okie doked them and retracted the stairs in flight to simulate a pressure bump then he could pick a more ideal dz on the flight path such as the Williamette Valley in OR or Reno as some has speculated. It also gives more credence to cooper having a cia/government affiliation.

Nicky's source of this information is pretty impressive. I'll allow him to elaborate.

According to your theory there would be a second bump or disruption that the crew stated never happened beyond the time they all agreed where they believe Cooper Jumped. going into Oregon and jumping unnoticed seems to be pretty hard to pull off.

When he states "retract" that means to raise and lock them. as mentioned above this could be done but would show on the panel. apparently, they dropped a few men and raised and locked the stairs prior to getting back to normal flight and speed.

Not necessarily, although I agree it would of been hard but come on the whole opp was hard, but it’s not impossible especially now that we know the hydraulics we’re strong enough to raise the stairs up in flight... We can’t put it past cooper to have found away to exit delicately also after the big oscillation/bump whatever we calling it these days the crew felt he was gone so it’s natural for them to not be as attentive. If cooper was familiar with the hydraulic controls maybe he had a way to manipulate them by raising them but not letting them lock then dropping them again. Nothing has turned up in the fbi DZ in almost 50 years not to mention the challenge of jumping over that terrain. I think it’s time we consider alternative possibilities. Also of note talking to Bill the SAT combi 727 didn’t have any difficulties with lowering the stairs in flight so why was flight 305 having so much trouble? I think because Cooper wanted them down as much as possible so the effect was stronger when he raised the stairs maybe hitting the down lever again as soon as the stairs were getting close the slip stream would of bounced it back into the fusel lodge some you’d think.

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According to your theory there would be a second bump or disruption that the crew stated never happened beyond the time they all agreed where they believe Cooper Jumped. going into Oregon and jumping unnoticed seems to be pretty hard to pull off.

When he states "retract" that means to raise and lock them. as mentioned above this could be done but would show on the panel. apparently, they dropped a few men and raised and locked the stairs prior to getting back to normal flight and speed.

Not necessarily, although I agree it would of been hard but come on the whole opp was hard, but it’s not impossible especially now that we know the hydraulics we’re strong enough to raise the stairs up in flight... We can’t put it past cooper to have found away to exit delicately also after the big oscillation/bump whatever we calling it these days the crew felt he was gone so it’s natural for them to not be as attentive. If cooper was familiar with the hydraulic controls maybe he had a way to manipulate them by raising them but not letting them lock then dropping them again. Shut I believe you were one of the ones that told me it was impossible to raise the stairs back up while in flight. Bills testimony proves other wise. Nothing has turned up in the fbi DZ in almost 50 years not to mention the challenge of jumping over that terrain. I think it’s time we consider alternative possibilities.

It would be easier to raise the stairs in flight than while parked on the ground.  As shown in the FBI sled tests, the stairs would be almost shut due to the airstream and the stairs hydraulic system could easily finish closing them.

And there is nothing to indicate that the stairs were down when the FBI test aircraft landed.

Yeah I’m not saying the stairs couldn’t fully close and lock in flight but I didn’t think to check the sled tests to see if they were able to good to know R99.

The other problem is Cooper not knowing how to lower the stairs. This presents a problem believing he would know pressure could fool the crew.