Rebuttal of two recent publications
2015 June 26
Preface by Duncan Steel
In a recent update of a previous post I wrote that I would be following up that post with another (i.e. the present item) in which the veracity or otherwise of a recent publication by Chen et al. would be rebutted. Links providing the full Chen et al. paper are available in that previous post.
With the above in mind the reader is invited to consider the rebuttal below by Victor Iannello of the Chen et al. paper, and also my brief comments that follow Victor’s text.
Another recent publication regarding MH370 that is also badly in error is an ebook entitled “MH370 & AF447″ which has been made available online by the author, one Siegfried Walther. It is a tissue of nonsense.
A few comments from Independent Group (IG) members regarding Walther’s ebook:
It was written by a lawyer and it shows. There were a lot of words and self-promotion but little substance.
Let me say that the article is a rambling mess and hardly the work product of a competent attorney. There are errors of fact as in most of the published work on this subject because the full scenario is complex and unique; further, there are a relatively small number of undisputed facts.
I stopped reading after page 18. That’s when I realized the entire theory rested on the likely-false assumption that ACARS was turned off at 1707…an unlikely assumption …certainly not a known fact.
A more-detailed summary of this egregious mistake in Walther’s purported analysis appears below, written by Mike Exner.
Comments on the Chen et al. publication
by Victor Iannello
2015 June 09
Here are my comments on “Malaysia Airlines Flight MH370: Water Entry of an Airliner,” by G Chen, C Gu, PJ Morris, EG Paterson, EG Patterson, A Sergeev, YC Wang, T Wierzbicki (2015); and the referenced paper “Impact Damage of the Challenger Crew Compartment” by T Wierzbicki and D Yue (1986).
- Chen et al. predict a fracture failure mode resulting in the rupture of the fuselage and wings for a vertical speed of 22 meters per second (43 knots) when the plane hits the water. Certainly the vertical speed greatly exceeded this value for a near-vertical entry into the water, resulting in a global failure of the structure. Therefore, by their own analysis, MH370 would have experienced a global structural failure with a near vertical entry.
- Chen et al. claim that because the surface pressure reached 6 MPa and the yield strength of aluminum is about 320 MPa (dependent on its manufacture and tempering), there was no local failure of the aluminum. In truth, the surface pressure and the tensile stresses in the aluminum are far from equal! Wierzbicki and Yue, for instance, found that a surface pressure of 1.2 MPa resulted in local tearing as the aluminum skin was elongated between the support rings to failure. (Do Chen et al. really believe that the skin of a B777 can survive a surface pressure of 6 MPa = 60 atm = 880 psi?)
- Neither paper analytically addresses the buckling failure of the thin cylindrical shell. Chen et al. acknowledge that this failure mode can occur at low impact velocities based on NASA experiments with a true aircraft. Wierzbicki and Yue also acknowledge that this mode may occur at lower impact speeds than for the other modes considered, but at least partially justify ignoring this mode because of the presence of the thermal tiles on the Shuttle. Obviously, there are no tiles on the skin of a B777.
In summary, the paper by Chen et al. cannot be used to justify the lack of debris with a near vertical entry into the water for the following reasons:
A. Using their own methodology, any reasonable entry speed will result in fracture failure and global failure of the structure.
B. Their predicted surface pressure would result in local tearing of the skin. Chen et al.’s assertion that there is no local failure because the predicted surface pressure is less than the yield strength of aluminum is incorrect.
C. Chen et al. completely neglect analyzing the buckling failure mode, without justification.
There is no justification in using this paper to explain the absence of any identified debris field.
Addendum by Duncan Steel: Victor (and also Mike Exner of the Independent Group) has had some email correspondence with the group of mathematicians and engineers which published the noted paper, and they have agreed with his comments about their paper as given above, Apparently this was a precursor publication for a larger, more-detailed set of papers on this subject. Such publications are to be welcomed, provided they are substantially better than this initial paper published by the American Mathematical Society.
To that I must add that Chen has now published online some responses to Victor’s comments above, and also queries from Mike. Having perused that eight-page commentary by Chen I would have to say that I find them to be more unsettling than the original publication, in that there is no real recognition of the waywardness of the methodology in that original paper, and Chen still insists that a high-speed impact into the ocean can be ruled out on the basis that no debris field has been identified. This is not science; it is persiflage.
Further, Chen derides the international media for hyping this publication (“overly enthusiastic news reports”). Given this announcement from the newsroom at Texas A&M University at Qatar, what other sort of response might have been expected from the media? It would appear that the people involved are out with the pixies both in terms of their science and engineering, and also their understanding of how the modern media work.
Comments on “MH370 & AF447″ by Siegfried Walther
by Michael Exner
2015 June 16
Unfortunately, the analysis of MH370 by Siegfried Walther is fundamentally flawed from the outset by his misunderstanding of how the ACARS system works in conjunction with the Inmarsat AMSS system. Starting on page 16, Walther states:
“The ACARS was switched off or became disabled at 01:07. The Transponder only switched off or became disabled some thirteen minutes later at 01:20 after MH370 signed off from Malaysian ATC.”
This statement is simply not true. There is no evidence whatsoever that the ACARS was switched off or became disabled at 17:07 UTC. All that is known for sure is that the ACARS transmission expected at 17:37 (30 minutes later) did not take place. From this fact, it is known that ACARS or the AES (or both) stopped functioning at some unknown time between 17:07 and 17:37. Absent any other information, it could be said that the probability that ACARS or the AES (or both) were switched off or failed at 17:07 is no more or no less likely than going off line at 17:20 or 17:36 or any other time in between 17:07 and 17:37 UTC.
But we do know something else. We know that the transponder stopped replying to interrogations at about 17:20, and we know the last VHF radio contact was at about the same time. Taking all three facts together, it is actually much more likely that the AES and/or ACARS stopped at the same time (i.e. circa 17:20, not 17:07).
Virtually everything that follows in Walther’s analysis is based on this false assumption that there was a 13 minute gap between the events. Take away that erroneous 13 minute gap assumption and the entire analysis that follows then collapses.
I would encourage Walther to go back and reconsider his theory under the much more likely assumption that the ACARS-AES, VHF and transponder all were switched off or became inoperative at about the same time (circa 17:20). All the evidence taken together suggests this is much more likely.
Note too that there is no evidence whatsoever that the VHF radio failed or was switched off. All we know for sure is that there were no transmissions from MH370 received after about 17:20. The radio may have been working fine, and if there were crew alive and listening, they could very well have heard every call to 9M-MRO (i.e. MH370), but did not respond for unknown reasons. We simply do not know if the VHF was off or on.