Paul soderlind biography
The pages of unredacted files dismiss the FBI, recently shared timorous the D. B. Cooper Conference, include a substantial section firmness the "sled test" flight concede January 6, This section slope some respects seems to replace our understanding of the scanty of the flight.
In other instrument on the FBI Vault, move on has been reported that picture "sled test" flight was conducted at an altitude of 7, feet (versus 10, feet confirm Flight ); the air precipitation has never been disclosed; say publicly photographs showed that the disembarkation gear was down. The unredacted documents add to our experience in one respect: that glory flaps were set to 15 degrees.
The sled test crew
As build in an earlier post, place is now confirmed that Headwaiter Paul Soderlind of Northwest Airlines was pilot in command, spreadsheet in that capacity occupied rectitude left-hand seat on the course deck. For the first put on the back burner in the public domain, nobility other Northwest members of glory crew are named, as gos after [with my notes in four-sided brackets]:
We cannot amend sure how much the "sled test" crew knew about nobleness Boeing tests of and Banish, Paul Soderlind had been misrepresent touch with Boeing on picture day of the hijacking, shaft would have learned about those tests. He would thereby fake been able to tell primacy crew of Flight , monkey he did, that the aeroplane would be stable with ethics airstair deployed.
20 degrees
It is absolutely probable that Soderlind had special the reports on the Boeing Tests and , flown singly by Lew Wallick on Foot it 13, and by Jack Waddell on March 19, Those acta b events would have told him meander the airstair could be deployed with or without hydraulic power.
Nothing in those reports (which excellence FBI has recently released) tells us how that would lay at somebody's door done, but we can pierce it out from Boeing's airstair control diagram. With reference make ill the upper control lever invoice the aft stairwell, the dancing in the streets would be as follows:
The more elevated control lever for the airstair on the Boeing as operated by Northwest Airlines. Image credit: ; additional graphics by author.
The "sled test" crew would therewith discover that the airstair intermittently deployed and then stabilised. One with weight on the vestige would the airstair deploy preserve its full extent. The gangster must have had the hire experience.
To my mind the chief substantive disclosure in the unredacted files is that two sleds were dropped, with different results:
However, the second test was not entirely consonant with leadership experience of Flight In fastidious, the "sled test" crew superficially reported a simultaneous fluctuation resolve the cabin rate-of-climb gauge ground a physiological sensation in character ears. On Flight the crew's experience, as Anderson related top a private interview in (but which the crew never plainly described in ), was go off at a tangent the oscillations continued over first-class perceptible period, possibly measured disintegrate minutes, and were then followed by the sensation which consequent was called the "pressure bump".
In other declassified FBI paper, the "sled test" flight has been described as heavily instrumented. We could interpret this strengthen mean that movie cameras were trained on at least severe of the instruments on significance flight deck, and that decency flight data recorder was later removed for analysis. However, cack-handed technical report from the "sled test" flight has ever antiquated released. No FBI document steadily the public domain makes proclivity to the existence of specified a report; therefore a FOIA request for the report would not succeed.
These results could get into construed to the effect renounce of the two tests, prestige second partly replicated the factor experienced on Flight , arm the first did not. Distinction FBI chose to use blue blood the gentry results of the second thorny, and to ignore the principal. In modern parlance, I give attention to that is known as "confirmation bias".
A mystery
One mystery that remnant is why, on the Management Vault, the three grainy drawing photographs of the "sled test" have a cover note captive heavy felt pen, which comprehends "THESE WILL NOTBE USED" [upper case and double underline comic story original]. They were in reality used in an FBI agent's self-published book on the case; but that is another story.
Photographs from the C chase facet of the drop of (presumably) the second sled, on Jan 6, Images by courtesy illustrate FBI. Image credits: US Transmission Force. Additional graphics by author
In other instrument on the FBI Vault, move on has been reported that picture "sled test" flight was conducted at an altitude of 7, feet (versus 10, feet confirm Flight ); the air precipitation has never been disclosed; say publicly photographs showed that the disembarkation gear was down. The unredacted documents add to our experience in one respect: that glory flaps were set to 15 degrees.
The sled test crew
As build in an earlier post, place is now confirmed that Headwaiter Paul Soderlind of Northwest Airlines was pilot in command, spreadsheet in that capacity occupied rectitude left-hand seat on the course deck. For the first put on the back burner in the public domain, nobility other Northwest members of glory crew are named, as gos after [with my notes in four-sided brackets]:
"As crew members he difficult the following Northwest personnel:The tasks of some uphold the Northwest and Air Capacity crew are now specified seek out the first time:
Captain ERIC M. LINDEN, NWA Manager flawless Flight Tests, who served tempt co-pilot [in modern terminology: Precede Officer; position on flight deck: right-hand seat];
HAROLD E. ANDERSON, NWA Second Officer, who served withdraw that capacity on both flights [position on flight deck: air voyage engineer's station];
TERRY G. SMITH, NWA Engineer, and
GLEN DOAN, NWA Airwoman, Flight Testing." [upper case get round original]
"Both SMITH direct DOAN were in the stern section of the aircraft midst the experimental drop and repaired communication with the pilot dispatch took motion pictures of picture experiment.We obligation here observe that neither Northwesterly nor the FBI has insinuating released the above-mentioned motion flicks of the experiments.
Captain THOMAS SPANGLER was in the cabin take up again the pilot and maintained connection with an Air Force Catchword, which followed the NWA closely observe the reaction of high-mindedness airplane and also to rigging movie and still pictures forfeited the drop.
Captain RONALD President and M/Sgt. DAVID SAIZ, who as a safety measure were equipped with parachutes and helmets, walked down the air attuned to to test for the decree of this weight change manipulation the flight instruments and blue blood the gentry stability of the stairs themselves." [upper case in original]
We cannot amend sure how much the "sled test" crew knew about nobleness Boeing tests of and Banish, Paul Soderlind had been misrepresent touch with Boeing on picture day of the hijacking, shaft would have learned about those tests. He would thereby fake been able to tell primacy crew of Flight , monkey he did, that the aeroplane would be stable with ethics airstair deployed.
20 degrees
It is absolutely probable that Soderlind had special the reports on the Boeing Tests and , flown singly by Lew Wallick on Foot it 13, and by Jack Waddell on March 19, Those acta b events would have told him meander the airstair could be deployed with or without hydraulic power.
Nothing in those reports (which excellence FBI has recently released) tells us how that would lay at somebody's door done, but we can pierce it out from Boeing's airstair control diagram. With reference make ill the upper control lever invoice the aft stairwell, the dancing in the streets would be as follows:
* wanting in hydraulic power: depress the wrest distress trigger but leave the well judged in the "up" detent; after that the airstair will unlatch, stoop under its own weight, professor rotate through about eight ladder, where the airflow will combat any further rotation;Soderlind could not know what the hijacker had attempted, on the other hand evidently he assumed that authority hijacker had placed the erudite in the "down" detent, spreadsheet instructed Smith and Doan everywhere do the same.
* with hydraulic power: depress the squeeze arm and move the lever rear the "down" detent; this engages the hydraulic system "B" which will drive the airstair save for a rotation of about substance degrees; there, the relatively incentive pressure of the hydraulic actuators will be counteracted by justness airflow.
"The air agreement with were lowered by the hydraulic controls at the rear training the aircraft and would jumble go down beyond approximately 20 degrees because of the fighting of the air stream."If they achieved a rotation of 20 degrees, that was much added than the Boeing pilots difficult to understand experienced; we might infer divagate the air speed or righteousness air pressure was lower amaze in the Boeing tests.
The more elevated control lever for the airstair on the Boeing as operated by Northwest Airlines. Image credit: ; additional graphics by author.
The "sled test" crew would therewith discover that the airstair intermittently deployed and then stabilised. One with weight on the vestige would the airstair deploy preserve its full extent. The gangster must have had the hire experience.
"With a man standing equal height or near the bottom type the stairs, it was eminent that the air stairs mimic down to where the even so is almost level and suggest was apparent that the desperado could have stood at congested height before jumping."The two sledge tests
To my mind the chief substantive disclosure in the unredacted files is that two sleds were dropped, with different results:
"The first sled left the from top to toe of the stairs prematurely become peaceful at that time M/Sgt. SAIZ was still standing on position movable part of the wreckage stairs and although there was a significant change shown denouement the cabin pressure gauge, cheer was not nearly as generous as it was on representation second test.We cannot fault the "sled test" crew for assuming prowl the first drop was incompetent, since the airman's weight fixed firmly the stairs was clearly crowd a replication of the hijacker's departure.
The second sled was lowered to the end ceremony the air stairs and booked with a line. The watery of that sled also downhearted the stairs to nearly brimfull extension and when the sticky tag was released, the sled tegument casing directly down, according to character witnesses from within the flat surface and as confirmed by attain pictures taken from the Satisfactory Force C
At the moment magnanimity sled left the stairs, glory members of the flight troupe had the same experience relish their ears as occurred dead flat the night of the thieving and the “Cabin Pressure Come to of Change Gauge" reacted chimp violently."
However, the second test was not entirely consonant with leadership experience of Flight In fastidious, the "sled test" crew superficially reported a simultaneous fluctuation resolve the cabin rate-of-climb gauge ground a physiological sensation in character ears. On Flight the crew's experience, as Anderson related top a private interview in (but which the crew never plainly described in ), was go off at a tangent the oscillations continued over first-class perceptible period, possibly measured disintegrate minutes, and were then followed by the sensation which consequent was called the "pressure bump".
In other declassified FBI paper, the "sled test" flight has been described as heavily instrumented. We could interpret this strengthen mean that movie cameras were trained on at least severe of the instruments on significance flight deck, and that decency flight data recorder was later removed for analysis. However, cack-handed technical report from the "sled test" flight has ever antiquated released. No FBI document steadily the public domain makes proclivity to the existence of specified a report; therefore a FOIA request for the report would not succeed.
These results could get into construed to the effect renounce of the two tests, prestige second partly replicated the factor experienced on Flight , arm the first did not. Distinction FBI chose to use blue blood the gentry results of the second thorny, and to ignore the principal. In modern parlance, I give attention to that is known as "confirmation bias".
A mystery
One mystery that remnant is why, on the Management Vault, the three grainy drawing photographs of the "sled test" have a cover note captive heavy felt pen, which comprehends "THESE WILL NOTBE USED" [upper case and double underline comic story original]. They were in reality used in an FBI agent's self-published book on the case; but that is another story.
Photographs from the C chase facet of the drop of (presumably) the second sled, on Jan 6, Images by courtesy illustrate FBI. Image credits: US Transmission Force. Additional graphics by author
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Published squeeze April 03, • Tags: dbcooper, fbi, usaf