You must be misunderstanding. I never said they locked in flight. the stairs never locked while Cooper was on them.

To close the door either an electric hydraulic pump has to be turned on in the cockpit, or a hand pump beside the lower control operated while either handle is held to the close position. The door will free fall open without hydraulic pressure, but the support arms may have to be pushed to an overcenter position.

This is what I was talking about with the stairs not going all the way down and having to apply pressure to lock them.

Assuming that the air stairs were deployed, it may be that the force of the airflow passing by would have been sufficient to spare the stairs from a tailstrike. The stairs have a large surface area and moving at perhaps around 100 knots when the nosewheel touches down would still generate a considerable force to push them into the fuselage.

Shutter, the nose wheel touching down means that the aft fuselage was rising and that would not generate a force to push the stairs into the fuselage.  Such an action would cause the stairs to rotate downward rather than upward.

When landing at Reno, the tower was asked to carefully watch the stairs and let the flight crew know when they struck the runway.  The stairs didn't contact the runway until the aircraft was actually turning off the runway at a very low speed.  The damage to the stairs was minor scrapes.

23:03, NW305: SEE ANY SPARKS COMING OFF THE TAIL AT ANY TIME ON AH TOUCHDOWN

23:03, RENO: NEGATIVE NONE AT ALL THE ONLY THING THAT'S VISIBLE ON THE TAIL IS LIGHT AH APPARENTLY ON YOUR RAMP

23:03, NW305: ROGER UNDERSTAND STAIR LAMPS AH STAIR LIGHTS

23:03, RENO: I DO SEE SOME AH SPARKS NOW JUST A FEW AH TRAILING YOU AH AS YOU'RE TAXIING IN

23:03, NW305: OUR AH PASSENGER TRIED TO DISEMBARK

23:03, RENO: I STILL DON'T AH GETTING A FEW SPARKS NOT VERY MANY AT ALL

23:03, NW305: OKAY WE'LL TRY TO SLOW OUR TAXIING HERE AS MUCH AH IT PROBABLY IS DRAGGIN AH

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Shutter, the nose wheel touching down means that the aft fuselage was rising and that would not generate a force to push the stairs into the fuselage.  Such an action would cause the stairs to rotate downward rather than upward.

Where did I mention anything about the nose gear? that should of been a quote..wasn't my writing..

You mentioned it in post #3839 above which is what I quoted in its entirety.

Another portion from the Aviation page..

As it turns out, the stair could not be opened much if at all at 170 knots during a climb, and the captain had to "have 'er about down to a hundred and sixty knots" and level off at 7,000 feet to get the resistance low enough. It makes sense that a higher angle of attack would cause a greater air load on the door due to the increased frontal area. It also makes sense that the airflow alone would be insufficient at any speed to completely re-close the door due to the geometry of the empennage and the continued downward hydraulic pressure. Once the door was open, the crew were able to climb again to 10,000 feet and keep the airspeed "in the vicinity of one seventy, one eighty [knots]".

Although the aforementioned hydraulic actuators would have provided damping, the swirling wakes from the landing gear and flaps—not to mention the aircraft turbulence inherent when flying low and slow over mountains in a storm—undoubtedly wrenched the stairs up and down considerably. Cooper's exit has been romanticized as a high-dive into the unknown, but it was more like trying to exit a springboard during an earthquake, with his own weight just exacerbating the problem. We know as much from Richard McCoy, Jr., a copycat hijacker who survived his jump (at the same airspeed) and was later captured and interviewed:

Unless one of you knows differently for a fact, I'm not sure there would be a 'locked down' position. If they operated hydraulically in both directions, then there would be. But according to Flyjack, they drop down by gravity, and the hydraulics are just used to pull them back up. If that is the case, then in their normal usage on the ground, they would just drop either to full extension or till they come to rest on the ground. There would not need to be a 'locked' down position.

Yes, there is a locked down position and yes, they are hydraulically lowered as well as free-falling (together). system A & B has 3,000 psi running through them. the only way they will not lock down is the failure of system B. the hydraulics also get the actuators/struts past center to lock. once they start to show wear (seals) they might need help getting the actuators past center by applying weight on the bottom step. pressure will remain in the system for 30 minutes after shutting down. if system B fails, you need to utilize the hand pump found under the fuselage to open and close the stairs.

We have storm shutters that act in a similar way. they crank up and down manually. while cranking down they sort of free-fall while loading the spring to assist cranking it back up due to the weight of the blades. the more popular and easier version is motorized.

At least Cooper didn't try to jump on the wing like this guy 


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