Help researching 1961 Electra crash

[BRDuBois]

Originally Posted by cordwainer

So am I understanding correctly that the plane would have had to spin around and head forward briefly in order to flip into its final orientation? If so, isn't this quite possible given the marshy ground (possible hydroplaning allowing it to spin around more easily), plus the multiple explosions noted by witnesses prior to the later tail explosion?

Yes, this might have happened. I discussed how it might have bounced forward in my document. In some fashion it had to be pointing forward. Point being, this means the CAB assertion that it slid backward is wrong, and until that is recognized it's impossible to grapple with the puzzle. Again, this is not a moral judgment about the CAB but a statement of fact. There's something wrong in how the CAB reported it.

This is not about gleefully pointing out that the CAB investigators were a bunch of idiots. There is a major error in this minor aspect of the investigation, and it raises a puzzle. So the questions are: How did the plane get into that position? What else (if anything) did the CAB get wrong?

If you reverse-engineer the plane's arrival at the final site, you start to see a very different impact scenario.

[BRDuBois]

Originally Posted by cordwainer

Seriously? You actually can write with a straight face, when the report says explicitly, "Lockheed Aircraft Corporation...provided a study of the flightpath based both on L-188 performance data and information disclosed during the investigation. Their study encompassed a ground envelope of reported flightpaths..."

That's flightpaths plural.

In other words the report states flat out that Lockheed provided an analysis that considered more than one flight path, so they obviously didn't provide the inner boundary only. And again, there can be no inner boundary without something to be the inner boundary OF.

The report writer said Lockheed analyzed the reported flight paths. It does not say Lockheed proposed different flight paths. It DOES say that Lockheed considered the inner path to be the only possible one.

[cordwainer]

The CAB report doesn't just assert, it states, "Based on the Lockheed study, Board investigators prepared the estimated flghtpath chart."

It's absurd, therefore, to purport the chart contains flightpaths or an envelope that was not in the Lockheed study at all.

Or, put another way: you can't castigate the CAB for including too little data on one aspect of the accident, then turn around and second-guess - with no basis for it - their inclusion of what you seem to think is too much data on another aspect.

I'm cool with theorizing, but that's not theorizing, nor is it healthy skepticism. It's illogic and incomprehension to a ridiculous degree.

[BRDuBois]

Originally Posted by cordwainer

The CAB report doesn't just assert, it states, "Based on the Lockheed study, Board investigators prepared the estimated flghtpath chart." It's absurd, therefore, to purport the chart contains flightpaths or an envelope that was not in the Lockheed study at all.

I don't know what your experience might be involving bureaucracy and the shedding of responsibility, but consider the situation. The CAB wants legitimacy for their investigation, so they invoke the Lockheed name in their report to give weight to their guesses. The CAB would have provided Lockheed with the witness statements as to flight paths, so to that extent those flightpaths were indeed part of the Lockheed investigation. Note the reference to the school house and the radar building in the flightpath map. These were probably landmarks used by witnesses in describing the flight. None of this means that Lockheed gave those paths any credence. The explicit statement that Lockheed considered the inner path to be the only possible one should tell you how much weight Lockheed gave in the end to the other paths that were offered as possibilities.

[G0ULI]

The report states that a number of flights were sampled at random after the crash and the data examined and collated. The curves shown reflect the findings from all the sampled flights and other data supplied by Lockheed. The report seems quite clear as to how the limits of the curves were established.

The bit of the report that states the aircraft "slid" to a particular spot, may be suffering from a change in the way we interpret the word slid. In modern parlance slid may be equated to skid and the two terms are frequently interchanged or used as synonyms.

At the time of the report, I believe that in using the word "slid", the investigators were referring to movement along and parallel to the ground, but not mecessarily in contact with the ground. The term "slid" was used to distinguish the movement from any aerodynamic lifting forces, i.e. flying. If they had used the word skid, that would have implied ground contact and associated gouge marks.

Given the dispersal of the wreckage, "slid" seems an appropriate term to use to describe how some large parts became separated in the ground, with little evidence in the photographs to show how they arrived at their final resting places.

[BRDuBois]

Originally Posted by G0ULI

The report states that a number of flights were sampled at random after the crash and the data examined and collated. The curves shown reflect the findings from all the sampled flights and other data supplied by Lockheed. The report seems quite clear as to how the limits of the curves were established.

Following flights were sampled to determine the typical speed and altitude. But the flight path of flight 706 was a plane in trouble and in an uncontrolled banking turn. I think it would be a misreading to think any later flights were used to determine the possible boundaries of the flight 706 path.

[cordwainer]

I don't know what your experience might be involving bureaucracy and the shedding of responsibility...

Well, 37 years of working with various government agencies for purposes of both research and reporting, ranging from the EPA to local regulatory bodies in multiple states, including CA [shudder], to the NIH. Including reviewing reams of data all the time as well. And, as you might have noted, the ability actually to research the existence of available archived records, beyond just asking one or two people then taking their word for it that those records don't exist. You know: professional research, which is part of what I do for a living, as opposed to the amateur version, which you're doing.

Sorry to be snarky, but there are some things where my expertise is, in fact, greater than yours, and so forgive me if I cop a little attitude here at what seemed a rather condescending comment, though I realize that was unintentional on your part.

The CAB wants legitimacy for their investigation, so they invoke the Lockheed name in their report to give weight to their guesses.

So did they also "invoke" the Lockheed name to "give weight to their guesses" about the aileron boost unit, in noting that it "was given a complete disassembly and inspection at the Lockheed Aircraft Corporation, Burbank, California"? Did they just toss Lockheed's name to give themselves legitimacy when they note later they "requested Lockheed Aircraft Corporation to perform certain ground tests" to check for the possibility of wing flap interference? Did they simply make up everything they claim Lockheed did to make it all sound good?

The CAB would have provided Lockheed with the witness statements as to flight paths, so to that extent those flightpaths were indeed part of the Lockheed investigation. Note the reference to the school house and the radar building in the flightpath map. These were probably landmarks used by witnesses in describing the flight. None of this means that Lockheed gave those paths any credence.

The report notes that "based on performance data" - not witness statements - the inner boundary was considered the only possibility. And the references on the map could also have come from topo maps, airport maps, the "aerial photo taken 9/17/61" that the plot in the chart was traced from, etc. "[L]andmarks used by witnesses..." is a pure guess on your part, so stating "probably" is a bit much.

The explicit statement that Lockheed considered the inner path to be the only possible one should tell you how much weight Lockheed gave in the end to the other paths that were offered as possibilities.

The report doesn't claim Lockheed gave any "weight" to other flightpaths. It does state their study "encompassed" reported flightpaths. As it certainly should - because a thorough and comprehensive report should include all reported data for comparison...making it all the more odd that you criticize the chart doing just that.

If the other reported flightpaths in the envelope are based on witness statements, it gives you some clues as to where they might have been located, and what angle they saw things from. And if the reported flightpaths are based on information from other pilots or ATC, it allows a comparison of normal flightpaths to that of an aircraft in trouble. Either way, it makes absolute sense that Lockheed would indeed have included the multiple-flightpaths envelope the CAB report states it did, and for CAB to include those multiple paths from the Lockheed report.

Look, what I and others are trying to say with increasing frustration is this: we're all on board with looking at the facts that DO exist, and trying to reconstruct the missing bits you're interested in from them.

But I'm not the only person who has tried to point out that you can't take a "surmise" and a "probably" and a "conjecture" and an "I have no trouble imagining..." and then string those together to reach any usable conclusion. You can't prove anything based on conjectures alone - you can only construct conjectures based on fact, not "feelings".

However, you seem increasingly unwilling to accept anything at all in the published reports as fact. To you, the CAB report might as well be non-evidence. That being the case, it's kind of pointless to keep on surmising - at least until you have more data you are willing to accept.

Because I do respect what you're doing, I'm going to bow out of this discussion unless/until I find more documents. Also because while I think it's OK for me to express some frustration with what I and others consider increasingly illogical arguments, I don't think it's OK or acceptable to keep hammering at you about it. Which I will end up doing if this thread continues along current lines.

Hoping to be back in late January, as noted previously, and wishing you a Happy New Year,
c

[BRDuBois]

Originally Posted by cordwainer

there are some things where my expertise is, in fact, greater than yours, and so forgive me if I cop a little attitude here at what seemed a rather condescending comment, though I realize that was unintentional on your part.

It wasn't condescending. I stated that I didn't know what your experience was. That's a true statement.

Did they simply make up everything they claim Lockheed did to make it all sound good?

I have no reason to think so.

The report notes that "based on performance data" - not witness statements - the inner boundary was considered the only possibility. And the references on the map could also have come from topo maps, airport maps, the "aerial photo taken 9/17/61" that the plot in the chart was traced from, etc. "[L]andmarks used by witnesses..." is a pure guess on your part, so stating "probably" is a bit much.

There were many things in the topo map that are not tagged. That these were in the flight path map suggests they had relevance for the flight path study. It's not much of a stretch to think they were referred to by witnesses, which is why I only used the term "probably", but I have no witness statements. I'm ok with saying the landmarks were possibly used by witnesses, if that's more acceptable.

The report doesn't claim Lockheed gave any "weight" to other flightpaths. It does state their study "encompassed" reported flightpaths. As it certainly should - because a thorough and comprehensive report should include all reported data for comparison...making it all the more odd that you criticize the chart doing just that.

If the other reported flightpaths in the envelope are based on witness statements, it gives you some clues as to where they might have been located, and what angle they saw things from. And if the reported flightpaths are based on information from other pilots or ATC, it allows a comparison of normal flightpaths to that of an aircraft in trouble. Either way, it makes absolute sense that Lockheed would indeed have included the multiple-flightpaths envelope the CAB report states it did, and for CAB to include those multiple paths from the Lockheed report.

I understand what you're saying. Yes, it's fair that the entire region be in the report. But it's not fair to say that Lockheed put this forth as the region of possible flight paths when the report explicitly denies that Lockheed considered any of the extended region to be viable. By saying that the envelope is based on the Lockheed study the CAB is stretching in my opinion.

you can't take a "surmise" and a "probably" and a "conjecture" and an "I have no trouble imagining..." and then string those together to reach any usable conclusion. You can't prove anything based on conjectures alone - you can only construct conjectures based on fact, not "feelings".

Correct. I phrase my conjectures and hypotheses to show what I think may have happened, and am looking for evidence to refute or support. My conjectures are not proof, nor are Megan's or anyone else's.

you seem increasingly unwilling to accept anything at all in the published reports as fact. To you, the CAB report might as well be non-evidence. That being the case, it's kind of pointless to keep on surmising - at least until you have more data you are willing to accept.

I accept everything in the CAB report until something makes it untenable. I accepted the root cause. I accepted some kind of slide until I understood the tree issue. The tail-first slide I've rejected for several years, of course.

it's OK for me to express some frustration with what I and others consider increasingly illogical arguments, I don't think it's OK or acceptable to keep hammering at you about it. Which I will end up doing if this thread continues along current lines.

If you think I'm making a bad argument, please point it out.

[Concours77]

Originally Posted by megan

I've not made any conjectures from memory, and if I have it would have included a statement along the lines of "in my opinion".The 35° attitude at impact - it was at near vertical, but you can't accept it because you've so latched onto the CAB making errors. The CAB are correct, in fact, if I were one of the CAB staff involved in the report, and still alive, I'd be hauling your sorry carcass into court for your libellous allegations as to my abilities, integrity and professionalism.

I agree. IMO is the least one can say in critiquing another’s work product.

Have you any comment on the “AI at ninety to one hundred degrees”?

Specifically, what telltales, what chronology? Was it used to support the “vertical bank” theory at first impact? (Right wing at Railroad Tracks)? Was its inclusion to support the first impact, or the second?

With respect,

concours

[Concours77]

Originally Posted by cordwainer

Thanks, this and your other details understood, appreciate the clarification.

So am I understanding correctly that the plane would have had to spin around and head forward briefly in order to flip into its final orientation? If so, isn't this quite possible given the marshy ground (possible hydroplaning allowing it to spin around more easily), plus the multiple explosions noted by witnesses prior to the later tail explosion?

Marshy ground. That would support my theory. Not “spinning around”, laterally, but flipped, vertically, arse about.

Skidding forward, upright, leading edge on, the main spar and the wheels entered the “ditch”, and stuck. Dragging a loosely attached tail section, the assembly flipped over, to land as we see it. Tail attached, very loosely, but connected via the keel beams.

At this point, what was left of fuel, (which Lockheed designed to be contained entirely in the wing), flooded the tail section, puddles under the wing, and lit.

Respectfully,

concours

[Concours77]

Originally Posted by BRDuBois

Yes, this might have happened. I discussed how it might have bounced forward in my document. In some fashion it had to be pointing forward. Point being, this means the CAB assertion that it slid backward is wrong, and until that is recognized it's impossible to grapple with the puzzle. Again, this is not a moral judgment about the CAB but a statement of fact. There's something wrong in how the CAB reported it.

This is not about gleefully pointing out that the CAB investigators were a bunch of idiots. There is a major error in this minor aspect of the investigation, and it raises a puzzle. So the questions are: How did the plane get into that position? What else (if anything) did the CAB get wrong?

If you reverse-engineer the plane's arrival at the final site, you start to see a very different impact scenario.

Only to add support to what looks like the preferred theory, mind that the tail section was attached to the wings throughout, via the keel beams. We know this because both assemblies came to rest together, though not correctly aligned.

The tail follows the airplane, always, in flight, and even here, in its demise. Not solidly attached by any means, but connected nonetheless. Imagine the tail wagging, as in dog’s tail, as it slid to its rest.

Your explanation is elegant, and enhances what is most likely the probable path.

Great respect,

concours

[BRDuBois]

Originally Posted by Concours77

both assemblies came to rest together, though not correctly aligned.

I suspect they were completely connected, and collapsed in slightly different orientations when the fuselage burned through.

[Concours77]

Originally Posted by BRDuBois

I suspect they were completely connected, and collapsed in slightly different orientations when the fuselage burned through.

precisely.

Only to add that if tail/wing stopped while fully connected and in proper structural alignment, the fuel mist explosion in the fuselage (tail) section would have met resistance at the dorsal, more robust area than the sides. Such an asymmetrical release of explosive gases would have rotated the tail and twisted it into the orientation we see in the photo....hat tip to cordwainer!

[BRDuBois]

Originally Posted by Concours77

Only to add that if tail/wing stopped while fully connected and in proper structural alignment, the fuel mist explosion in the fuselage (tail) section would have met resistance at the dorsal, more robust area than the sides. Such an asymmetrical release of explosive gases would have rotated the tail and twisted it into the orientation we see in the photo.

I doubt that we can make this connection. We don't know if it impacted as a flip-over, which would be minimal spray, or coming down from some height as in my missing-forward-fuselage sim run which might give a considerable spray. And whether the conjectured fuel-air explosion would move the empennage is a guess too far, seems to me.

Far as I can see, accepting the CAB description means envisioning the aft section essentially sliding to a stop and then bursting into flames. Once you realize that it can't have been sliding backward, the questions multiply and the certainty drops.

[BRDuBois]

Originally Posted by megan

I wish you would read and digest the report, it says

The Captains artificial horizon indicated that it was receiving a signal of 90 to 100 degrees at the time it ceased to function

I have no clue what an artificial horizon might read if the plane is in a violent right-turn about its vertical axis. Presumably this depends on the technology of the time.

[G0ULI]

The older type vacuum-driven attitude indicators have bank limits of approximately 100° to 110°, and pitch limits of 60° to 70°. These limits are imposed by the mechanical construction of the gyroscope. Modern designs frequently exceed these limits.

Electrically driven gyros can be designed to display 360° movement in any axis.

[Concours77]

Originally Posted by G0ULI

The older type vacuum-driven attitude indicators have bank limits of approximately 100° to 110°, and pitch limits of 60° to 70°. These limits are imposed by the mechanical construction of the gyroscope. Modern designs frequently exceed these limits.

Electrically driven gyros can be designed to display 360° movement in any axis.

Limits are important, but not germane. What would be more instructive would be “lag” (response) of the instrument in dynamic maneuvering...

My exception would be using the instrument’s reading at impact to support (or defeat) a “conclusion” of attitude at RR impact....we are left with the photo of the embankment, and wildly discrepant witness testimony.

So. Why would CAB report “when it ceased functioning” instead of reporting “at second impact”? Is that the case? It leaves open a conclusion that it was somehow relevant to a discussion of initial impact. Sloppy.

It also opens the discussion of bias. When did the boost unit “cease functioning?” We are given a conclusion that it was damaged by fire, a rather obvious statement, but it biases the readers to a conclusion that fire alone damaged the boost unit, after impact.

[G0ULI]

It is standard practice to estimate instrument readings from the faint indentations left in the dial face at the moment of impact. The wing contact with the railroad embankment was unlikely to have been severe enough to produce such a mark. We are left to conclude that the second impact with the ground that detatched the nose section was the one that produced the witness marks used to estimate the aircraft attitude at that point.

It is very tempting to try and read between the lines and second guess the investigators, especially when an element of doubt has been raised about certain aspects of the report. I prefer to believe the report should be read without trying to put a modern interpretation on the wording. It is clear the investigators at the time knew what they were doing.

What I find incredible is the accuracy with which cables in the control runs were expected to be assembled and installed. Cable runs of hundreds of inches were expected to terminated and fastened to tolerances measured in hundredths of an inch or better than one part in ten thousand. The aircraft was originally built with the precision of a Swiss watch, an incredible technological achievement. Despite the disruption, the investigators were still able to draw meaningful conclusions from the wreckage.

[BRDuBois]

The CAB mentions "The relatively slow, progressive disintegration which occurred in this accident makes it impossible to assess the in-flight significance of instrument readings which might otherwise be reliable."

Page 104 of my last release, as a footnote.

[Concours77]

Originally Posted by G0ULI

It is standard practice to estimate instrument readings from the faint indentations left in the dial face at the moment of impact. The wing contact with the railroad embankment was unlikely to have been severe enough to produce such a mark. We are left to conclude that the second impact with the ground that detatched the nose section was the one that produced the witness marks used to estimate the aircraft attitude at that point.

It is very tempting to try and read between the lines and second guess the investigators, especially when an element of doubt has been raised about certain aspects of the report. I prefer to believe the report should be read without trying to put a modern interpretation on the wording. It is clear the investigators at the time knew what they were doing.

What I find incredible is the accuracy with which cables in the control runs were expected to be assembled and installed. Cable runs of hundreds of inches were expected to terminated and fastened to tolerances measured in hundredths of an inch or better than one part in ten thousand. The aircraft was originally built with the precision of a Swiss watch, an incredible technological achievement. Despite the disruption, the investigators were still able to draw meaningful conclusions from the wreckage.

Thanks Gouli, a patient and thoughtful message for all.

I have been considering the quality of construction myself. Impressive. The long cable runs terminating in four inches of a connection devised by daVinci, threads.

To be accurate, it is not the cables that adjust to tension, they are finite in length, and subject only to variations in temperature, in Lockclad, even the temperature deviation is mitigated by the locking aluminum sheath around the stainless stranded cable.

The 4.2 inch stainless threaded couplers and brass junction blocks were the culprits.

When considering the precision in cabling, one wonders why the cables were not simply thimbled, and held in place by safetied bolts.

Tension could be adjusted with deflection in the cable, without the need for “safety wire”.