Poll

Do you believe Cooper lived or died. the option are below to cast a vote...

0% Cooper lived
6 (9.7%)
25% Cooper lived
4 (6.5%)
35% Cooper lived.
2 (3.2%)
50% Cooper lived
13 (21%)
75% Cooper lived
14 (22.6%)
100 Cooper lived
23 (37.1%)

Total Members Voted: 57

Author Topic: Clues, Documents And Evidence About The Case  (Read 787698 times)

Offline Chaucer

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Re: Clues, Documents And Evidence About The Case
« Reply #8010 on: August 10, 2022, 12:04:56 AM »
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Persistent pesky questions about them stairs and the oscillations and bump...

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...going down a couple of steps past that hinge point is going to lower the stairs enough to create pressure changes in the cabin that would be noticeable in the cockpit cabin altitude instrument...     ...this time, he goes way down the steps as far as he can, perhaps to the very end of the stairs, and jumps.  Cooper's weight on the stairs will not lower them to the same degree as they are lowered on the ground.  But when Cooper steps off those stairs they slam up into their closed position but don't lock there...     

In that clip from the Treat Williams movie, when the stunt guy jumps off the stairs, they retract very slightly and slowly. They certainly don't 'slam' shut, even momentarily. I would imagine the pilot could feel a bit of change on the pitch influence, but I don't see it re-sealing the cabin momentarily and causing a pressure event. For the stairs to behave in the way described, I would guess that Cooper would have to have pulled the emergency release, which should disconnect them from the hydraulic system and allow them to free-float. But I'm told that did not happen, that he did not pull the emergency release. So would there be that much variable from plane to plane, how much the stair door would be able to move while still connected to (dampened by) the hydraulic system?  ...??
I don't have a good answer for that either. I have heard different things - the stairs hydraulics were not deployed and the stairs were freefloating and vice versa. Regardless, it seems that the pressure bump was simulated during the drop test in January 1972.

Here is what I do know:  the cabin rate of climb and descent gauge uses a sensor in the cabin to measure cabin pressure altitude. During an unpressurized flight - like the Cooper hijacking for example - it will read approximately the altitude that the aircraft is at. It will respond just like the flight altimeter - going up and down with the aircraft.

I propose that the 727 was experiencing what's known as a phugoid.

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If the plane was experiencing a phugoid, that would be reflected as oscillations in the cabin rate of climb indicator. I think the slow extension of the airstairs by Cooper caused phugoid oscillations in the aircraft that the crew noticed on the gauges. When Cooper jumped, the crew experienced a pressure bump - a rather well-known phenomenon in aviation when the pressure of the cabin increases dramatically - that usually causes your ears to "pop". When that happened, the airstairs were no longer descending and the aircraft stabilized from its phugoid.

Thus, while both phenomena - the phugoid oscillations and the pressure bump - were caused by Cooper's behavior on the airstairs, they were distinct things. Whether the crew, the airline flight ops, or the FBI understood the difference when it happened or immediately after is the question.

Chaucer, as an aeronautical engineer my main time was in flight dynamics which included aircraft performance and stability and control.  Longitudinal aircraft stability involves a short period mode and a longer mode called the phugoid.

The short period mode is typically completely damped out within a couple of seconds and is not generally noticeable to the pilot.  I have never noticed anything that I could identify as the short period mode in flying powered general aviation aircraft and unpowered sailplanes.

I have more than 1000 hours of flying time in unpowered sailplanes which spend about 90 percent or more of their time in maneuvering flight.  Consequently, for sailplanes, it is desired that the longitudinal stability be essentially zero.  This means that when the pilot takes his hand off the stick the sailplane will diverge longitudinal as well as about the other two axes.  Longitudinally, this divergence is the phugoid and it will never dampen itself out.  Without corrections by the pilot the sailplane will end up in a spiral and if it stalls it will spin.  Long flights in sailplanes can be very tiring.  My longest flight sailplane flight was about 7 hours and 20 minutes.  After landing, it took me at least 5 minutes to get out of the cockpit and stand up and I felt lousy the next day.

Powered aircraft, even fighter aircraft, generally spend about 90 percent or more of their time in straight and level flight.  Again, the short period mode dampens out in only a few seconds.  But the phugoid mode may take 4, 5, 6, or more minutes, repeat minutes, to dampen out naturally if it ever does so.  Hand flying early jet airliners at high altitudes was particularly tiring for the pilots due to the phugoid.  Consequently, the autopilots were typically activated as soon as possible after takeoff and stayed on until the descent for landing.
Flying a sailplane sounds like fun. Too bad I'm a nervous flyer. Go figure.

Quote
But the phugoid simply cannot explain the cabin pressure altitude oscillations or the bump when the stairs hit the fuselage when Cooper jumped.  It is just not possible.
First, in my post I said that the phugoid would explain the cabin pressure oscillations, but NOT the bump. The bump, I think as has been clearly shown, is caused by the door swinging back up after Cooper jumped.

Second, since this would appear to be your area of expertise, I would hope you could explain why a phugoid mode can't explain the oscillations in the cabin pressure rate of climb. I may be wrong about it, and I only offered it up as a possibility. At its face, it appears to make sense. Rather than simply tell me it's not possible, tell me why.

Simple.  The autopilot or the pilot hand flying the aircraft would cancel out the phugoid and it would not be a factor in the cabin pressure oscillations.

This is not an insult.
I certainly think if the autopilot was on, then a phugoid would be easily dampened. I don't think the autopilot was on.

With that said, would flying unpressurized at night through clouds with little frame of reference, impact the ability of the pilot to detect a phugoid and thereby react to it? Rataczak obviously had a lot of other things to be distracted about.

I'm not arguing strongly in favor of a phugoid. I'm sincerely asking. If it's not possible, then it's not possible.

It's not possible.  Again, the phugoid was never a factor.

Flying at night through clouds and unpressurized doesn't mean anything.  The gyroscopic instruments on their instrument panel was all they needed for reference.

In 1971, in addition to an FAA Pilot's Certificate, I also held an FAA Ground Instructor Certificate that permitted me to teach pilots Basic, Advanced, and Instrument Flying.  While I never had a pilot's certificate for instrument flying, I have quite a few hours of flying under a hood with a safety pilot on board and this included ILS and other instrument approaches.  Some of that flying was done in two-place sailplanes with the only gyroscopic instrument being a "needle and ball" which predates today's "turn coordinators".

The above is not an insult.   
What specific instruments on the Boeing 727 would the crew used to identify a phugoid?
“Completely unhinged”
 

Offline dudeman17

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Re: Clues, Documents And Evidence About The Case
« Reply #8011 on: August 10, 2022, 12:28:15 AM »
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I'll leave an explanation of the aft stairs hydraulic system to others, but the drop tests prove the point about the bump and cabin pressure oscillations.

I don't need an explanation of hydraulic systems, I know how they work. What I'm saying is that there is something in all this that doesn't make sense. Things attached to hydraulic systems don't move all that freely, as their movement is restricted and dampened by the systems, as evidenced in the footage of the Treat Williams movie jump. The pilots did note the pressure bump, both in Cooper's jump and in the subsequent test. Flyjack has posted evidence that Cooper did not pull the emergency release, I don't think I've heard one way or the other about the test. I just have a hard time seeing the door rebound to the point of momentarily slamming shut while it's connected to the hydraulics, again as evidenced by the movie footage.

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In 1971, in addition to an FAA Pilot's Certificate, I also held an FAA Ground Instructor Certificate that permitted me to teach pilots Basic, Advanced, and Instrument Flying.  While I never had a pilot's certificate for instrument flying...

You were not instrument rated as a pilot, yet you were rated to teach instrument flying as an instructor? How does that work?


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The pictures of that backpack (Hayden's parachute) indicate that it was put together from a collection of parts that came from different designs and did not itself have a formal designation.

Please detail that for me. Please.
 

Offline Olemisscub

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Re: Clues, Documents And Evidence About The Case
« Reply #8012 on: August 10, 2022, 02:24:11 AM »
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Hayden provided the two backpack parachutes that were given to Cooper and he said they were identical.  The surviving backpack is now on display at the WSHM in Tacoma, WA.  The pictures of that backpack indicate that it was put together from a collection of parts that came from different designs and did not itself have a formal designation.

So this is a Frankenstein's monster parachute?



 

Offline Robert99

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Re: Clues, Documents And Evidence About The Case
« Reply #8013 on: August 10, 2022, 02:33:05 AM »
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It's not possible.  Again, the phugoid was never a factor.

Flying at night through clouds and unpressurized doesn't mean anything.  The gyroscopic instruments on their instrument panel were all they needed for reference.

In 1971, in addition to an FAA Pilot's Certificate, I also held an FAA Ground Instructor Certificate that permitted me to teach pilots Basic, Advanced, and Instrument Flying.  While I never had a pilot's certificate for instrument flying, I have quite a few hours of flying under a hood with a safety pilot on board and this included ILS and other instrument approaches.  Some of that flying was done in two-place sailplanes with the only gyroscopic instrument being a "needle and ball" which predates today's "turn coordinators".

The above is not an insult.   
What specific instruments on the Boeing 727 would the crew used to identify a phugoid?

No instruments exist for identifying a phugoid except the pilot's posterior.  And again, the phugoid was not a factor in the Cooper hijacking.
 

Offline Robert99

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Re: Clues, Documents And Evidence About The Case
« Reply #8014 on: August 10, 2022, 03:05:40 AM »
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I'll leave an explanation of the aft stairs hydraulic system to others, but the drop tests prove the point about the bump and cabin pressure oscillations.

I don't need an explanation of hydraulic systems, I know how they work. What I'm saying is that there is something in all this that doesn't make sense. Things attached to hydraulic systems don't move all that freely, as their movement is restricted and dampened by the systems, as evidenced in the footage of the Treat Williams movie jump. The pilots did note the pressure bump, both in Cooper's jump and in the subsequent test. Flyjack has posted evidence that Cooper did not pull the emergency release, I don't think I've heard one way or the other about the test. I just have a hard time seeing the door rebound to the point of momentarily slamming shut while it's connected to the hydraulics, again as evidenced by the movie footage.

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In 1971, in addition to an FAA Pilot's Certificate, I also held an FAA Ground Instructor Certificate that permitted me to teach pilots Basic, Advanced, and Instrument Flying.  While I never had a pilot's certificate for instrument flying...

You were not instrument rated as a pilot, yet you were rated to teach instrument flying as an instructor? How does that work?


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The pictures of that backpack (Hayden's parachute) indicate that it was put together from a collection of parts that came from different designs and did not itself have a formal designation.

Please detail that for me. Please.

I'll go with the FBI's sled tests that show the aft stairs back up to the fuselage within a couple of seconds of the sled separating from the stairs.  I would refer you to FlyJack on DropZone if you want to discuss the aft stairs hydraulic system further.

In the 1971 time frame, in order to get an FAA Instrument Ground Instructor Certificate, it was necessary to pass an appropriate FAA written examination for that certificate.  There were additional requirements for each endorsement (Basic, Advanced, Instrument) including teaching experience of one kind or another.

In order to get an FAA Instrument endorsement on a pilot's certificate, it was necessary to pass an appropriate FAA written examination for that endorsement.  There were additional requirements including having a certain number of total flight hours logged and a certain number of instrument flight hours (under a hood or in actual weather) with an FAA Flight Instructor - Instruments.  Plus a recommendation from that instructor and passing a flight test administered by an FAA Flight Test Examiner for Instruments.

On the parachute, take a look at the picture Olemisscub has posted above and that explains it all.
 

Offline JAG

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Re: Clues, Documents And Evidence About The Case
« Reply #8015 on: August 10, 2022, 08:17:06 AM »
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I'll leave an explanation of the aft stairs hydraulic system to others, but the drop tests prove the point about the bump and cabin pressure oscillations.

I don't need an explanation of hydraulic systems, I know how they work. What I'm saying is that there is something in all this that doesn't make sense. Things attached to hydraulic systems don't move all that freely, as their movement is restricted and dampened by the systems, as evidenced in the footage of the Treat Williams movie jump. The pilots did note the pressure bump, both in Cooper's jump and in the subsequent test. Flyjack has posted evidence that Cooper did not pull the emergency release, I don't think I've heard one way or the other about the test. I just have a hard time seeing the door rebound to the point of momentarily slamming shut while it's connected to the hydraulics, again as evidenced by the movie footage.

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In 1971, in addition to an FAA Pilot's Certificate, I also held an FAA Ground Instructor Certificate that permitted me to teach pilots Basic, Advanced, and Instrument Flying.  While I never had a pilot's certificate for instrument flying...

You were not instrument rated as a pilot, yet you were rated to teach instrument flying as an instructor? How does that work?


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The pictures of that backpack (Hayden's parachute) indicate that it was put together from a collection of parts that came from different designs and did not itself have a formal designation.

Please detail that for me. Please.

I'll go with the FBI's sled tests that show the aft stairs back up to the fuselage within a couple of seconds of the sled separating from the stairs.  I would refer you to FlyJack on DropZone if you want to discuss the aft stairs hydraulic system further.

In the 1971 time frame, in order to get an FAA Instrument Ground Instructor Certificate, it was necessary to pass an appropriate FAA written examination for that certificate.  There were additional requirements for each endorsement (Basic, Advanced, Instrument) including teaching experience of one kind or another.

In order to get an FAA Instrument endorsement on a pilot's certificate, it was necessary to pass an appropriate FAA written examination for that endorsement.  There were additional requirements including having a certain number of total flight hours logged and a certain number of instrument flight hours (under a hood or in actual weather) with an FAA Flight Instructor - Instruments.  Plus a recommendation from that instructor and passing a flight test administered by an FAA Flight Test Examiner for Instruments.

On the parachute, take a look at the picture Olemisscub has posted above and that explains it all.

Another variable at play between the Treat Williams movie observation and the NW305 SLED test may be the speed and altitude of the air planes.  While I am not 100% certain, I seem to remember that the speed and altitude of NW305 were not the same as that of the plane and stunt in the movie.  So perhaps these different conditions may have had some impact on the action of the stairs when actor jumped.  For example, maybe the movie 727 was going slower and therefore the slip stream wasn't quite as strong where it would help push it back up as dramatically during the hijacking ?  Anyway, just throwing this into the discussion.
 

Offline Chaucer

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Re: Clues, Documents And Evidence About The Case
« Reply #8016 on: August 10, 2022, 11:06:37 AM »
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It's not possible.  Again, the phugoid was never a factor.

Flying at night through clouds and unpressurized doesn't mean anything.  The gyroscopic instruments on their instrument panel were all they needed for reference.

In 1971, in addition to an FAA Pilot's Certificate, I also held an FAA Ground Instructor Certificate that permitted me to teach pilots Basic, Advanced, and Instrument Flying.  While I never had a pilot's certificate for instrument flying, I have quite a few hours of flying under a hood with a safety pilot on board and this included ILS and other instrument approaches.  Some of that flying was done in two-place sailplanes with the only gyroscopic instrument being a "needle and ball" which predates today's "turn coordinators".

The above is not an insult.   
What specific instruments on the Boeing 727 would the crew used to identify a phugoid?

No instruments exist for identifying a phugoid except the pilot's posterior.  And again, the phugoid was not a factor in the Cooper hijacking.
Oh, you were referring to the gyroscopic instruments relating to the plane’s location, not the phugoid. Got the wires crossed.

I can certainly understand how the stairs swinging back up after the HJ jumped would caused a large change in pressure (the “bump’). I have a hard time believing that the slow, downward deployment of the stairs caused by Cooper’s weight moving down them would cause changes in cabin pressure in an unpressurized aircraft strong enough to be detected by instruments.

And the word “oscillations” is odd too. Oscillations indicate variations or changes at regular intervals over a period of time. What, in terms of physics, about the airstairs would cause “oscillations”?

Maybe I’m just being pedantic.
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Offline Robert99

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Re: Clues, Documents And Evidence About The Case
« Reply #8017 on: August 10, 2022, 01:57:41 PM »
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It's not possible.  Again, the phugoid was never a factor.

Flying at night through clouds and unpressurized doesn't mean anything.  The gyroscopic instruments on their instrument panel were all they needed for reference.

In 1971, in addition to an FAA Pilot's Certificate, I also held an FAA Ground Instructor Certificate that permitted me to teach pilots Basic, Advanced, and Instrument Flying.  While I never had a pilot's certificate for instrument flying, I have quite a few hours of flying under a hood with a safety pilot on board and this included ILS and other instrument approaches.  Some of that flying was done in two-place sailplanes with the only gyroscopic instrument being a "needle and ball" which predates today's "turn coordinators".

The above is not an insult.   
What specific instruments on the Boeing 727 would the crew used to identify a phugoid?

No instruments exist for identifying a phugoid except the pilot's posterior.  And again, the phugoid was not a factor in the Cooper hijacking.
Oh, you were referring to the gyroscopic instruments relating to the plane’s location, not the phugoid. Got the wires crossed.

I can certainly understand how the stairs swinging back up after the HJ jumped would caused a large change in pressure (the “bump’). I have a hard time believing that the slow, downward deployment of the stairs caused by Cooper’s weight moving down them would cause changes in cabin pressure in an unpressurized aircraft strong enough to be detected by instruments.

And the word “oscillations” is odd too. Oscillations indicate variations or changes at regular intervals over a period of time. What, in terms of physics, about the airstairs would cause “oscillations”?

Maybe I’m just being pedantic.

The gyroscopic instruments do not have anything to do with the plane's location or the phugoid.

The oscillations referred to the fluctuations in the cabin pressure.  They were caused by Cooper having to get below the hinge point on the stairs so that he could create enough space to jettison the items that were not tied to his body and/or parachute.

The bump was caused by the aft stairs hitting the fuselage immediately after Cooper jumped.

Again, I would strongly recommend that anyone interested in aircraft navigation, performance, the air traffic control system, or anything aeronautical go to the FAA's web page, work your way to their publications page and download the free publications related to your interests.  And read them.  In my always humble opinion, the FAA publications are extremely good.

The above is not an insult.
 

Offline Shutter

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Re: Clues, Documents And Evidence About The Case
« Reply #8018 on: August 10, 2022, 02:19:00 PM »
Again, we have an aircraft that is sealed with the exception of the open stairs..any disruption will be noticed. now, if they opened the cockpit window prior to anything else, it would be a different story but hardly plausible..
 

Offline Chaucer

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Re: Clues, Documents And Evidence About The Case
« Reply #8019 on: August 10, 2022, 03:46:04 PM »
So, now you’re thoroughly confusing me, Robert. Why did you mention gyroscopic instruments being “all they needed” if they don’t have anything to do with anything?

Also, Rataczak’s initial report stated: “oscillations in the cabin rate of climb” and his statement to the FBI simply said “oscillations”.

There’s no reference to “pressure oscillations” until May 30, 1973 (FBI 41, p. 30). In that instance, the author of the 302 is referring to the transcript I have attached below. Note that while the person doing the transcribing inserts something about “pressure”, Rataczak doesn’t actually mention it.

There is a reference for “pressure fluctuation” on January 9th, 1972 (FBI 18, p. 414) after the drop test, but “fluctuation” is singular not plural. This is obviously in reference to the bump, and not oscillations.

“Fluctuation” in regards to pressure isn’t mentioned again until February 12th, 1980 after the money was found on Tena Bar. (FBI 9, p. 195)

There are a few conclusions that could be drawn here, but to me it indicates that the oscillations were not considered to be pressure-related until much later on and likely incorrectly due to the insertion of “pressure” into Rataczak’s quotes when he doesn’t actually say that. Instead, it’s possible that the oscillations were not pressure related at all - at least not directly.

The prevailing theory is that the movement of the stairs caused by Cooper walking down them caused the pressure in the cabin to “oscillate” or “fluctuate”. What evidence to we have that the oscillations were directly related to pressure at all?

In aviation, the term “oscillations” are usually used to refer to changes in longitudinal stability such as phugoid oscillations, short mode oscillations, or pilot-induced oscillations (porpoising).

Again, considering the plane was unpressurized, it’s possible the oscillations were not at all related to pressure, but to altitude. Or to say it another way “the changes in pressure were a reflection in changes in altitude rather than changes in pressure by another means (the airstairs moving)”.

What I mean is that the lowering of the airstairs by Cooper slowly walking down them created drag causing a disruption to the pitch of the aircraft and inducing minor long mode oscillations that the crew detected on the rate of climb indicator for an unknown amount of time and ceased when Cooper jumped.

This is something good ole hominid theorized over a decade ago.

I’m no expert, but it’s food for thought. I’ll have to dig a little deeper into it. I want to talk to some more people who are a lot smarter than me and know a lot more about this crap than I do and who can tell me if I’m full of it or not.


« Last Edit: August 10, 2022, 04:31:34 PM by Chaucer »
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Offline Chaucer

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Re: Clues, Documents And Evidence About The Case
« Reply #8020 on: August 10, 2022, 04:11:01 PM »
Re: Anderson’s statements in 2014:

“Very minor disruption of the slipstream [drag not pressure]”

“We all agreed the gauges were detecting a disruption of airflow [drag not pressure]”

“…the gauges never detected any further major airflow disruptions after that ‘thud’ [drag not pressure]”

Almost exclusively through the interview, Anderson refers to the oscillations as changes related to drag and not pressure. Only once at the very end of the interview does Anderson combine the two terms when he refers to “oscillations/pressure changes”. He’s not wrong, the oscillations WERE related to pressure and reflected on the pressure gauges, but only, in my opinion, as changes in altitude due to, in Anderson’s words, “disruptions of airflow”. 

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Offline Shutter

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Re: Clues, Documents And Evidence About The Case
« Reply #8021 on: August 10, 2022, 04:17:34 PM »
You are dealing with pressure changes, period..drag is found on everything in the sky.
 

Offline Shutter

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Re: Clues, Documents And Evidence About The Case
« Reply #8022 on: August 10, 2022, 04:19:52 PM »
The gauges deal in differencial pressure, psi, pounds per square inch..they are not drag gauges..boeing tests showed little if any drag with the stairs down..
« Last Edit: August 10, 2022, 04:24:48 PM by Shutter »
 

Offline Chaucer

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Re: Clues, Documents And Evidence About The Case
« Reply #8023 on: August 10, 2022, 04:27:18 PM »
First, I want to be clear that I am referring only to the oscillations not the bump. I think it’s clear that the bump was a pressure event.

To that end, the oscillations were pressure-related as well, but as a result of a change in altitude.

In other words, instead of:

STAIRS MOVING ——> PRESSURE CHANGES IN CABIN ——-> OSCILLATIONS DETECTED ON GAUGES

You have:

STAIRS MOVING ———> CHANGE IN AIRFLOW/DRAG ——-> CHANGE IN PITCH ——-> OSCILLATIONS OF AIRCRAFT ——-> ALTITUDE CHANGES ———> PRESSURE CHANGES DETECTED ON GAUGES

And Soderlind told the crew that the airstairs would be OK to fly with down expect for some disruption of pitch. It’s in the 302s. We’re not talking enormous altitude changes - just enough to be detected on the gauges.
« Last Edit: August 10, 2022, 04:29:27 PM by Chaucer »
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Offline Shutter

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Re: Clues, Documents And Evidence About The Case
« Reply #8024 on: August 10, 2022, 04:36:11 PM »
Differential pressure: the difference in pressure between the pressure acting on one side of a wall and the pressure acting on the other side of the wall. In aircraft air-conditioning and pressurizing systems, it is the difference between cabin pressure and atmospheric pressure.

Pressure, not drag..the gauges picked up the differences