The overall site image from the impact end (page 41 of my latest version) appears to show a thin white line going off to the upper left with people along that line. The tracks are blocked, and they were reported cleared on the first day. Shadows indicate this image is about noon. I take that while line to be a measuring tape, so it suggests they were mapping on day one very soon after the smoke was gone.

That was my guess, and how I described it in my cockpit resources document mentioned above, but I have no practical experience.

That's the kind of feedback I'd really like to get. I'm frustrated by an acquaintance who lives near me. He's a retired Northwest Electra (among other types) pilot, and he refuses to look at this project or discuss it in any way. Mumph.

PM sent.

Whirl mode was brought up in passing, but never seriously considered. The more curious question has to do with airspeed and height. The official reports say the plane was "somewhat low" or words to that effect, but when it passed the tower it was about half the normal height. It was only doing about 165 knots when it hit and should have been doing 225 if I recall right.

There was extensive investigator discussion of engine failure as a cause as reported in the papers, but then in the official reports there is not a word about the low and slow path. My simulation says that just a little more speed would have saved them, and the official report concludes that they were too low to effect recovery, but there's no hypothesis given to explain the flight path.

I have looked in vain for a detailed cutaway drawing of the wing showing the routing of the aileron and engine controls. I was wondering if the aileron control cables or turnbuckle could have recoiled and interfered with the engine controls, rolling the power back a bit on that side. That would certainly increase the bank angle by reducing propellor wash across the wing. It all rather depends on whether all the control cables were routed along a single channel in the wing, something I have been unable to establish.

If this was possible and did occur, that would suggest that the aileron cable parted during the takeoff run while the aircraft was still on the ground. The reduced power available could account for the slow acceleration and climb characteristics observed.

That does give rise to all sorts of questions as to whether such a power rollback would be reflected in the cockpit controls or be detectable by the crew.

The cabling ends at the boost unit which for ailerons is midship. The actuating force to the ailerons is carried within the wings by push-pull tubes. I presume that's one reason the emergency response to a cable failure is to switch to autopilot. The autopilot controls the boost unit hydraulically, bypassing all cabling.

Hi.
 

Whirl mode ending in fatal impact was well described in the two accidents I reviewed. My experience as pax in the Electra involved seated portside abeam the engines and witnessing it first hand. It is impressive. In my case the aircraft was short, and full power added whilst level at one hundred feet. The two port engines were wobbling and the aircraft was shaking so bad the passengers were alarmed. There were a couple of screams as I recall.

In the takeoff roll, at rotation, the stresses are at max on the mounts, and whirl mode is one loose motor mount away.

Have you the logs and maintenance records? I would consider whirl mode, especially as one engine left the airframe before the others?

I never saw it while flying in an Electra. After my dad's crash I was probably on one three or four times. Thought it was a good plane. A friend shared that he'd noticed it on at least one occasion. All I can say is that after the wing geometry changes there were no more catastrophic instances, and of course the P3 is still going strong.

I have almost nothing. Got a whole bunch of manuals supplied by a few retired NWA pilots and from downloads. Got the press photos that triggered this whole thing. Got the official reports and a bunch of newspaper archive stories.

A friend has an in with some Lockheed folks; he hopes to shake something loose. Lockheed has a reputation for saving documentation, but they've never answered my requests. One reason for putting this project out in front of the public is to get some buzz going, and maybe a FOAF will come forward with some musty folders. Small hope, but that's about all I have.

Been a while since I worked on the Electra as a maintainer. A few practical notes I can add; when we would deactivate the Autopilot, we would do so by depowering via a three phase ganged circuit breaker. The AP amp & cb were in the avionics rack on the flight deck at floor level,just behind & to the right of the FE's position. I flew many times on the flight deck & as the Electra was prone to Dutch roll,we would pull & reset the AP cb. It is extremely (impossible) unlikely for the flight controls and engine power controls to mechanically interfere. The engine controls being routed along the wing leading edge & flying controls along the trailing edge. They are also physically separated on the flight deck & within the fuselage.

woptb

Thanks for the info. Another possible issue eliminated in determining exactly what happened and the sequence of events.

Extremely poor quality film footage of crash site....
 

Dear Mr. Hagstrom:
On YouTube there is a video that contains an amateur film of the crash site. I'm not allowed to post URLs, but you can find it easily by knowing the title is "Chicago O'Hare Takeoffs and Landings From 1961 Video 1" and it was uploaded by davidevo2

Crash scene footage begins at 3:42. The camera work is absolutely horrible, but it does briefly show, for example, workmen up on the power lines who appear to be inspecting things rather than doing repairs. A large amount of the footage is shots of the power lines, in fact.

I can't make heads nor tails of most of it it's so shaky, blurry, and constantly shifting...except I could tell the flowers in one shot are sunflowers because I know sunflowers well enought to recognize them no matter how lousy the filming. Which is my optimistic way of expressing the very faint hope, since you know the scene so well, that you might likewise spot something recognizable that would help answer some of your questions. And even if it's no help at all, I thought you might want to know about it. Wishing you all best with your research, c

Wow, that's incredible, thank you very much.

The photographer must have been very excited, because it's just all over the place. I presume the scaffold near the powerline is something to support the slack wires over perhaps a road or a railroad line until they are tightened, but that's a guess. I'll freeze-frame it and see what I can see.

He's got an excellent frame or two of the initial impact, showing wing fragments left on the east side of the track. There's some clue to the depth of the impact hole where I suspect engine four hit. The sequence as a whole gives me a much better feel for the terrain than I had before. It looks like the photographer was on the access road and on an embankment east of the tracks. It's going to take a little time to map this out.

This must have been several hours after the crash, possibly the following day. That scaffold wouldn't go up instantly, but it looks like a portable rig that would be pretty quick to handle.

It's going to take some time to process this. Thank you.

The entire sequence was just over 2900 frames. About 820 of those were clear enough and stable enough to be useful. He appeared to shoot from three locations - (1) close to the main fuselage first impact site in the trees, about 300 feet west of the tracks, (2) just east and below the tracks and virtually under the high tension line, and (3) on a hill east of the tracks, elevated above them and slightly southwest of position #2. Since he was panning I should be able to map his location pretty closely.

The scaffolding looks like a permanent installation, not a temporary structure. It appears to have concrete footings. It doesn't seem to have any equipment. It's possible the platform on top supports lights that aren't obvious from this angle.

Three panoramas made from these sequences might be instructive.

Very glad if it ends up helping at all.

Also, I didn't see any mention of this in this forum or your PDF, so forgive me if I'm telling you something you already know. And I don't want to get you all excited about what may be nothing.

However, ALPA's archives are not with NARA. Instead they chose Wayne State University as their repository. As before, I can't post a URL, but try

reuther[dot]wayne[dot]edu[slash]taxonomy[slash]term[slash]9

and if that's incomprehensible look for the Walter P. Reuther Library site, Collections.

I didn't see a direct reference to this crash in the (admittedly few) collection descriptions I skimmed through. But there are a lot of records, with a descriptive PDF for each sub-collection within the ALPA group. And there are definitely documents and correspondence from 1961 and 1962, though the catalog is not necessarily specific enough to trust with regard to details of every document in every box. And none of it appears to be digitized, so you'd be in for a long, dusty slog through a ton of old paper.

Still, on the off chance it might help.

Cheers,
c

Wow, thanks again. I found the crash records in Box 12 folder 1. Now I need to contact a human.

Meanwhile, I've finished two composites. One is practically standing on top of the impact site. He was probably chased away from there pretty quickly. That they didn't have perimeter control at that point tells me he was shooting on the afternoon of the crash. The second is from his final shooting location, a hill southeast of the railroad track first impact point.

https://ibb.co/nasY7b

https://ibb.co/g83Fnb

I'm working on a third, taken under the power lines. There are fewer visual cues to tie the images together, and he took two sequences from slightly different locations.

Pretty amazing to see this after all these years.

Astonishing! I never expected to see colour images after all this time.

I note that there are regular poorly focused vertical and horizontal markings spread across the still frames. I initially thought that suggested filming through a wire fence, but watching the video reveals these are apparently just scratch marks on the film. I would guess the lens as being the equivalent of a 200 or 400mm modern zoom lens. Pretty hard to get steady hand held shots and probably no compensation in the viewfinder from more normal wide angle lenses. I believe the other aircraft shots were made with a tripod support if they are all by the same photographer.

I think the chaotic panning was simply an effort to try and include all of the scene, shooting handheld while not having a decent viewfinder to confirm what was being filmed.

Truly remarkable what turns up on the Internet.

I think the vertical lines are scratches on the film. This was 8mm, and probably converted to digital form after at least 35 years of being played mechanically. There's a very curious horizontal line in the foreground on the left side of the composite done near the crash site. I really don't know what to make of that. There is also a wire draped higher up in that image, which suggests the plane managed to go entirely underneath it.

I've heard back from Wayne State U, and they'll be looking for the crash materials next week. The ALPA never answered my emails, so I had pretty much no hope of getting their stuff. This is a real gift, but as I told my wife it will make for a long weekend! Lockheed-Martin also never answered, and Delta couldn't begin to care about NW history. Next week should be interesting.

In the first panoramic composite, the power lines can be seen descending at the extreme right side of the image. There are two parallel lines clearly visible.

The second composite would appear to have been framed looking between the two power lines that are descending from left to right across the image.

The angles and spacings look very similar considering the difference in scale caused by changing the filming position.

This is quite a development. Some amazing information from cordwainer. It'll be very interesting to see what Wayne State University have in their archives.

I'm still trying to nail down where he was. He shows no sign of zooming, but he could have had something like a 3-lens turret, pretty common for a movie camera of the era. If you compare the AtImpact image with the press photo that I use for my overhead view in my document (page 41), He's somewhere on a line roughly between point Y and the lower left corner of the image. He could conceivably be filming through the railroad wires running beside the tracks.

His second shooting position was down below that structure I mentioned earlier, and if you view the video its footing is clearly quite a bit above him. Also note in the OverTrack image that there's a power pole on his near side of the track almost between him and the impact site (the red spot in the distance), and the next power pole to the left is on the opposite side of the track. So the low-voltage line crosses the track at that point, and presumably the high-tension line does as well. The highest two frames of the OverTrack image show the bottom conductor of the high-tension line. On page 70 of my document you can just barely pick out a couple poles at the bottom of the picture, and see that the power lines are crossing the tracks.

At the pole in front of him, the lines drop down quite quickly but are parallel and under some tension at least. It appears that the string of poles is dropping down into the lower elevation from which he filmed up at the structure (landing lights?). So the droop on the right side of the OverTrack image is not severed lines, and if they were cut it was beyond a following pole off to the right.

I'll work on a composite from that lower vantage some more. It's pretty terrible film.

booke23 - this is what I keep begging for, and the reason I release my research in stages. I ask people to pass it around in the hopes that it will come to the attention of someone who knows where to find documentation.

I've uploaded an aerial photo of O'Hare from 1961. Forgot I had the thing.

https://ibb.co/krms0w

Truly thrilled the ALPA archive may be of help.

I should be clear, I'm not a pilot. But your project is exceptionally intriguing from the standpoint of accomplishing a kind of time travel - creating a window into the past where you can view the scene as it was on the dates of and surrounding the crash.

So while I'm of no use when it comes to analysis of the flight sequence, I can at least try to locate other information out there useful for purposes of identification, mapping, and orientation around the site.

I'll also keep working on ferreting out other sources where photos, documents, or footage are hiding.

BTW, I don't want to clog the thread, so please let me know if you'd prefer PMs to posts.

A few last notes though: with regard to nailing down exact locations, have you done any comparisons with topo maps from the time period? Or with the various City of Chicago planning documents for O'Hare ? Together they might provide clues to structures and features for orientation, are drawn exactly to scale, and in the case of the topos and one engineering report provide info on elevation and terrain.

There are USGS historic maps available for free, none from 1961 , but I can point you to a 1957 Chicago quadrangle and a 1963 Elmhurst map with enough detail they may be of use.

Several O'Hare master-plan documents are available in the Internet Archive. They contain quite a number of maps, diagrams, and photos potentially relevant to your re-creation...though you'd be the best judge of that, of course. 1958 master plan volumes are avaiable, including the first-stage Engineering report, also the 1960 fueling system agreement and the 1962 Revenue Bond Improvement plan which probably contain the most contemporaneous look at the airport and area.

I can also look, if you like, for surveys and documents from public utilities, and from the rail companies tangentially involved (if I'm reading the maps and reports correctly those would be the Chicago and North Western or the C.M.St.P&P or both). It's possible their files might even include information from the crash and/or related repairs.

Um...nonetheless, if any of these are way off the mark, please let me know. Likewise if there is anything in particular you think would be useful. I actually enjoy historic research, and would be pleased to be of assistance wherever possible.

Cheers,
c

cordwainer,

This project is like an electronic archeological dig. It comes with a big chunk of emotional load, obviously, and I get a lot of free psychoanalysis out of that. But mostly it's a puzzle.

I've talked with the Chicago & Northwestern historical museum. They have all the archives but nothing to the level of detail I need. If you've read the missing-engine puzzle you can see that they might have provided a key bit of evidence in their job ticket journal.

I'd be very interested in topo maps for the area as of that date, if for nothing more than locating our photographer. Topo maps would give power and phone lines. Maps from 57 and 63 would be close enough to be useful. A man who was a pastor at a church near the crash site told me that the area was virtually untouched for many years after the crash, and the scattered homes visible in the panorama suggest it was pretty stable for some years before. The whole area is now warehouses. When I was recreating the flight with a simulator, I kept crashing into warehouses. By the way, my videos are on Youtube and can be found searching for N137US.

I've loaded the third composite. It's several sequences, explained in the notes.

https://ibb.co/gYGsHb

Topo maps and other
 

Just sent you a PM with some links to topos and 2 planning reports
c

After looking at his other three videos, it's clear he had a zoom lens and uses it A LOT. Probably too excited to use it for the crash scenes. There's a bunch of great clips there; love those old planes.

Big thanks to cordwainer for the information. One of the topo map links he sent was pure gold. I've clipped out the O'Hare portion of it, overlaid it with the CAB report map showing the flight path as a half-transparent image. The landmarks line up exactly, validating the CAB cartographer.

https://ibb.co/e4n1dG

Turns out the impact point was virtually on top of the A from my other image. I had guessed it was farther north.

Additional records...
 

1) The corporate records of Northwest Airlines are archived at the Minnesota Historical Society

www2[dot]mnhs[dot]org[slash]library[slash]findaids[slash]00110.xml

The 1961 O'Hare crash is specifically noted in the Accident Files, which also references a section of general info on accidents between 1929 and 1974.

2) There was also a Coroner's Jury inquest held October 4, 1961, for which a transcript theoretically exists. The Cook County Medical Examiner's office is responsible for warehoused inquest archives, which are public documents. BUT: be forewarned there are no end of complaints about how difficult, time-consuming, and expensive it is to get those records. Numerous genealogy researchers have expressed frustration with obtaining even simple reports, or cited charges of $5 per page of sworn testimony from inquests.

One researcher's attempts to obtain a large inquest file are detailed in this article, which gives you an idea of what you might be facing:
www[dot]chicagonow[dot]com[slash]chicago-history-cop[slash]2016[slash]02[slash]cook-county-medical-examiners-office-is-a-joke-especially-on-valentines-day

I did find a few articles about the inquest that discussed some of the witness testimony - will PM a Dropbox link for you to access the clippings. Though you've probably already seen them...

c

I'm frankly amazed that the MNHS has records, because retired NWA people and the NWA History Center told me that Delta would have everything, and Delta won't answer me. At any rate, I see the entry in the MNHS index and have asked my sister in St Paul if she's willing to go look at it. Thank you very much for the lead. How do you know this stuff?

As for Cook County, I'd heard about that, and the obvious records to get from them are autopsy files, and I'm not real sure I'm ready for that. It's only been 55 years, after all. Give it some time. :)

Thank you for the clippings. I think I have most of that after searching newspaper archives, but I'm going through them.

I definitely wasn't suggesting you obtain autopsy records - that would be too grim, and I wouldn't be so insensitive.

Instead, the suggestion is to obtain the transcript from the Coroner's Jury hearing. That would contain the verbatim statements from the eyewitnesses and first responders, as well as from some of the investigators at the scene.

The point of the Coroner's Jury hearing was primarily to determine whether the deaths were accidental or if some person or party bore responsibility (e.g., were there grounds for manslaughter or negligence charges). The verdict was the crash was an accident.

My impression was that the Coroner's role at that time was similar to that of the Coroner in British jurisprudence. This is no longer true, but in 1961 Coroner was an elected position, and didn't actually require any medical knowledge or background.

A lot of the testimony and evidence are probably identical to that given at the CAB's separate hearing 6 days later. Since thus far it is proving impossible to locate any of the CAB transcripts or detailed investigation files, it seemed the Coroner's Jury hearing transcript would be the next best thing. If you could actually get it, which as noted is the problem.

Cheers,
c

Got the ALPA files. They are mostly clippings. A quick scan shows several items of significant interest.

First, there's a cover letter for the ALPA report being sent to the CAB in August '62. I mentioned in my document that the ALPA seemed to be in a rush to get their report out, and the cover letter suggests that the reason is so the ALPA could put a stake in the ground regarding the crew. As a union voice, this is a major role for the ALPA, and they wanted to get the ALPA view into the CAB report. I blamed this rush for the apparent errors in the ALPA report.

Second, the Chicago Trib carried a graphic on their last page showing the CAB scenario of a right wing hit, the plane spinning around and sliding backward some 800 feet. As I demonstrated, the plane had to have slid forward until it flipped at the end. I called it unconscionable that the CAB would put this out on the afternoon of the crash. The CAB never walked back this scenario, and the ALPA clippings include a much better image than the one I got from the Trib microfilm conversion.

Finally, there is a closeup of a piece of debris on the railroad tracks. If I can identify its location in the wing, this will tell us that the wing was destroyed at least to that station at the tracks. My maintenance manuals may or may not allow me to identify it.

This is an exciting development, and thanks again to cordwainer.

I've assembled the back page scans. These scans are informal and low-res, intended for review. I'll have them redone as high-res. You can see the power line at the bottom of the picture. The positions of people on the track exactly match their positions on page 41 of my document, so this is a wider-framed version from the same exposure. Page 70 of my document shows the terrible quality that came from the Trib microfilm.

https://ibb.co/hMoFA6

Note that it shows the right wing breaking off at the tracks. In my opinion, the break should be shown between engines three and four. I suspect the reporter conveyed the CAB story to the artist wrong, but having worked at a newspaper I can attest that it's sometimes more important to be finished than to be correct.

This is the same image which under higher resolution shows a large object on the tracks, but no large object was there by the time a photographer got to the tracks.

Whatever the object was on the tracks, it probably wasn't that heavy. The apparent speed with which it was removed suggests something that could be shifted using just manpower. So probably some part of the wing structure rather than an engine or other massive part.

It's an interesting puzzle.

If the object was light enough that a half dozen guys could pick it up, I could see them doing that and putting it on the west (unused) set of rails. But they wouldn't carry it away entirely; that's the job of the crash investigators. When a news photographer got there later that day and shot the scene, the papers carried a picture of an unimposing chunk of aluminum sheet between the rails, looking like twenty pounds tops. If an engine had been there to shoot, they sure would have taken that. And the chunk of aluminum sheet was way too small to be the object lying on the east tracks in the overhead shot.

The railroad guys are experts at clearing tracks, picking up stuff and moving it. Probably have a small flatcar with a jib boom on it, the railroad equivalent of a pickup truck, for jobs like this. Once they had the go-ahead from investigators, it was probably a ten or twenty minute job.

When you add in the whole missing-engine conundrum as I laid it out in an upcoming chapter and uploaded standalone as https://we.tl/2iOuz04If7, the simplest explanation is that the number four engine was blocking the track. But the evidence is thin.

The photo that shows a chunk of debris lying between the railroad tracks looks to me like a highly crushed and distorted wing rib with some additional components attached. Given that the aircraft wing is assumed to have made first contact with the ground in the vicinity of the raised embankment, that sort of debris is to be expected. That is why propose that the large object on the tracks was part of the outboard wing.

Contact with the embankment is undoubtably responsible for the loss of the outboard engine but where I can see a large chunk of wing breaking off and remaining on the rails at the top of the embankment due to snagging and air resistance, the engine is an altogether different matter. The engine and gearbox are a compact mass of metal travelling at over a hundred miles an hour. There is absolutely no way it would have remained on top of the embankment. Sheer inertia would have carried it a considerable distance and/or buried it in the ground on the far side of the embankment.

We know that propellor strikes were evident across the embankment, so it is reasonable to assume that a section of the wing outside of the outer engine broke away as the aircraft struck the rising embankment. The propellor strikes them shattered the propellor of the outer engine and shock loaded the engine to the extent it too broke away from the wing structure. The remainder of the aircraft with three engines continued in flight until making contact with the ground some distance from the embankment. This would certainly account for three of the engines being found relatively close to each other with the fourth some distance away.

The inertia contained in the engine and gearbox components can be estimated by the depth to which some penetrated the ground, eight feet deep in at least one case if I recall correctly from your report.

The extent to which the railroad tracks were apparently distorted in the crash is a matter of inches. Pretty much what you might expect from contact with a high speed but relatively light weight structure such as a wing. Solid contact with a gearbox or engine block would surely have broken or severely dented the rails, not just shifted them sideways a bit. Apart from the apparent track movement, there is remarkably little obvious damage to the tracks at all.

That is why I am absolutely convinced that whatever the large object was on the railroad tracks, it was not an engine. Even railway engineers of the time would know that an engine was a significant part of the crash sequence and that it would not be moved without the specific instructions of one of the air crash investigators. A large piece of wing alloy skin flapping in the breeze would be another matter and probably treated far more casually. Shifting that off the lines and down the embankment would seem a sensible idea for those entrusted with clearing and examining the tracks.

There's certainly room for disagreement here, and I understand what you're saying. I discuss the physics of the impact at some length, but not being an engineer it's no more than an attempt to get my head around it.

I wouldn't expect propeller strikes to detach the engine on an Electra or any other plane. I've put up an image of the damage when an Electra prop makes a substantial ground strike at https://ibb.co/knWn8R. There is no visible damage to the engine or nacelle. I'm not suggesting that prop four hit the tracks and that this was sufficient to tear off the engine. The prop strikes across the tracks were from prop three.

I contend that the plane was at about a 35 degree bank and the wing hit the track just inboard of engine four. So engine four wasn't skittering along the tracks, it was stopped pretty much dead by a direct impact with the embankment. It then bounced more or less vertically off the sloped embankment, and landed on the rails.

The best reason for saying the large object imaged on the tracks was the engine is precisely what you pointed out earlier. A bunch of guys could pick up a mass of aluminum and move it out of the way. If they had done so, that mass would have been what the papers ran instead of the ten or twenty pound chunk that they showed as the first impact debris. The reports note that the wing was reduced to small fragments at the embankment. In the various pictures there are bits of metal all over the area.

As I say elsewhere, the question is not to determine the odds of a torn off engine landing on the track. The question is, given a large object lying on the track, what are the odds it's engine four? If it's not, then it's an amazingly large piece of wing considering the shreds that the rest of the wing was reduced to in that area.

Whether it was an engine or other debris, I'm confident the railway workers had permission to move whatever they moved. As I wrote in the engine puzzle chapter, it sounds like there was miscommunication among the investigators, but I'm pretty sure the rail staff got what they thought was an authoritative ok from someone.

Holy Toledo. My sister just sent me the contents of a NWA folder at the Minnesota Historical Society that cordwainer suggested.

The most important single document is a letter from Don Nyrop dated Dec 21 '62, discussing the CAB report that was released Dec 13. Nyrop says the report was "issued prior to the availability of all of the scientific data and tests necessary to establish a probable cause for the accident. The Board has been notified that there are at least 22 specific errors in the report it released on December 13. In our opinion, the Civil Aeronautics Board's findings are based on incomplete data, an unfinished analysis, and on conjecture."

Nyrop's letter was under a cover note that said it was clearly not intended for public consumption, but could be used as the basis for private responses.

I said elsewhere that it felt like the Lockheed engineers thought the CAB guys were a bunch of fools. Turns out NWA thought so too.

Holy Toledo.

My goodness, brought that thread to a screeching halt didn't I?

I have said that the CAB investigators seem to have been held in low regard by Lockheed and Northwest. Evidence for Northwest's view is documented in Don Nyrop's letter. Evidence for Lockheed's view comes from the flight path map. I owe Lockheed a word of appreciation here.

When a reader first suggested I look at turn and bank calculations, I started by overlaying the CAB map with circles to measure the turn radius at different points. I said that not all who drew the map would have been thinking of my reverse-engineering their work. When the CAB report said that Lockheed held the inner curve to be the only possible path, it didn't dawn on me until much later what that signified.

To say that this was the only possible path is a remarkably assured statement. It does not sound like Lockheed was simply more discerning in its choice of witnesses to believe, which might have resulted in a statement of heightened confidence but certainly not one of such bald certainty. And no other means of recording the flight path is mentioned in any report.

The only reasonable explanation for Lockheed's statement is that the team calculated the path. I have no direct evidence, but I will assert this. With slipsticks and pencils they ran iterations just as I did with an Excel spreadsheet, and they kept on until they had derived a path that ended at the impact point.

When they had finished the path calculation, they said they had found the only possible one. When I ran the Excel routine I came close to the same path. When I flew the simulator I came up within a wingspan of the same path. Lockheed knew it was the only path not because witnesses agreed but because they ran the math.

This means that Lockheed knew the plane hit at much less than a vertical bank. The Lockheed team would have known how debris was distributed, and if I am correct that engine four was left at the tracks then Lockheed knew the plane hit at no more than 35 degrees.

The inner curve on the map was not something drawn by a draftsman with a French curve, nudging and tweaking while a bunch of guys looked over his shoulder until they had a consensus. It is the plot of their turn and bank calculations. The CAB's giant looping flight path range, trowelled on top of Lockheed's calculations, must have been like a slap in the face.

The inner curve is like a hand print in cement; it memorializes Lockheed's presence. It is evidence that due care was taken by at least some of the investigators, and it's a permanent record of what the Lockheed team was thinking.

Lockheed had all the design parameters and design flight characteristics of the aircraft. While their conclusions may match your findings, you both have a significant stake in trying to prove that neither the aircraft nor the flight crew were inherently at fault. Lockheed would be particularly keen to eliminate any suggestion that the aircraft was inherently unsafe and to a certain extent it would have been ideal from their point of view if mishandling of the emergency by the flight crew was contributory to the crash.

The accident investigators on the other hand were required to consider all possibilities and not just the ones that conveniently fitted a certain conclusion. While they might have to accept the findings of Lockheed's engineers, they would certainly treat that information with suspicion, because of vested interests in the company.

The fault in the aileron rigging was clearly something that needed to be addressed, but it exonerated Lockheed from direct responsibility for the accident.

The most common finding of pilot error could not be attributed to this accident either, because the aircraft became uncontrollable once it left the ground since the ailerons did not function as they were effectively disconnected from the flight controls. It certainly seems that some attempt was made to discredit the pilots by suggestions that the autopilot controls could have been used to control the aircraft. Had the autopilot not been flagged inoperative and the breakers pulled, I have a strong suspicion that this would have been the finding of the investigation. Such a finding would have been grossly unjust given the time constraints the crew had to find a solution to the problem, it is unlikely that such action to regain control would have been considered in the time available.

I am inclined to believe that the aircraft struck the embankment at an angle greater than 35° of bank, possibly as much as 60°, but certainly a lot less than wings vertical. The flatter angle of 35° would, I think, have resulted in a less damaging impact with the ground and perhaps the possibilty of some survivors. The damage to the aircraft points towards a much heavier impact with the ground which is why I theorise a steeper angle of bank on impact with the railway embankment. I am aware of course of your arguments for the shallower angle of bank supported by ground and other witness marks.

As to the engine being left on top of the embankment, this would have to have been recorded somewhere in the paperwork. The fact that no statement of any sort record the engine being found there, or moved from there, suggests that whatever was on the embankment, it wasn't the engine.

Because of the solidity and physical inertia of the engine and gearbox, in order for them to be deposited across the railroad tracks without damaging the tracks, the engine would have to have struck the embankment lower down, broken away and lost inertia before bouncing up in the air and landing on the tracks. While there is nothing inherently impossible with this scenario, it would have left hugely obvious marks on the approach side of the embankment and does not fit with the propellor strike marks found across the embankment.

Additionally, there should have been considerably more shrapnel and bits of metal and oil scattered across the tracks, which surely would have been photographed, officially or otherwise. It simply doesn't make sense that the engine ended up lying across the tracks given everything else that has been revealed.

I wouldn't expect the CAB to take outside advice without qualification. If someone pointed out that the plane was upside down instead of right side up as the CAB said, I'd think they'd at least look at it again.

We have no idea what size hole was left in the embankment; we have no good images of it. There's a hint in this new film, but the quality is too poor to have any confidence in it.

We don't know whether there was paperwork showing engine four came off at the tracks. We have no paperwork. That's why this is a puzzle. There were probably hundreds of pictures, but the files are gone. News photographers may have taken dozens more. News photogs burn through an enormous amount of film. But they discard what's unusable, and I don't have access to their archives.

I've uploaded a chart of my simulator flight overlaid on the CAB map. The red dots show the approximate size of the plane and represent about half second intervals. The map shows that my flight agrees with Lockheed's path within 50 or 75 feet.

https://ibb.co/fKZcF6

Hi Megan, thought you gave up on me.

As I discuss on page 54, I'm trying to relate ground marks to the airplane structure to figure out how it made the final bounce. The bounce seems to have been driven by the main gear and the ground is somewhat soft. The C indicates what looks to me like the right gear dent.

Not having any luck identifying this piece of debris, so I'll put it out here and see if anyone has an inspiration.

https://ibb.co/c8oKoR

I could imagine a piece of piping going through the holes, and being ripped out when the plane hit. But piping never bears against a hard edge like that in plane construction. It would be cradled in a saddle and strapped down. Maybe the holes are for lightening, and whatever it supported was bolted at what is here the top ends of the legs, and when it ripped apart it gave way at the holes.

Alternatively, since the holes seem to have a distinct concavity toward the right, perhaps this was some kind of guide meant to trap and lead something being inserted. The only possibility that occurs to me is in replacing the fuel scavenge pump, which is roughly the right size. But I don't find that at all convincing.

At any rate this is another example of the size of debris at the tracks. Compare this to the image I published last release:

https://ibb.co/kCQQ7m

The newspaper editor would have selected the most impressive image the photog brought back. So these can be taken to be representative samples, and it matches the reports saying the track debris was in shreds.

The plane had a 67% fuel load. The wing tank would have exploded like a water balloon when it hit the embankment, and the planking would have torn into individual sheets or partial sheets.

By elimination, all I can come up with to explain the large object on the tracks is to say it's engine four.