[ventus45]

Just an update of "happenings" over on Victor's blog of late.

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David says:
August 7, 2017 at 3:52 am

@Victor. About the JW discussion you indicate, “… nor do I think it is productive to repeat that discussion here”. I take it that your reservations are no longer germane?

My aim in looking into the flap damage, being informed by the Silk Air analysis, was just to see what that meant about the possibility of there being a glide at end-of-flight

If we could eliminate a pilot possibility using debris damage analysis that would remove this uncertainty and it might do more than that. While it is understandable that the focus of the search would have priority over search width, the focus appears to be settled around CSIRO advice. Yet there is no sign of a comprehensive damage analysis, which of course should include the flaperon. Maybe the Malaysians are at it silently? (rhetorical!)

@ALSM. You and others have come to the conclusion that there was no ditching, “with the Flaperon in a down position”. However that leaves open a ditching with it in the neutral position though the ATSB concluded the flaperon separated from that.

You say the only other alternative flaperon separation explanation to the ruled out flaperon-down ditching would be following….., “Separation of the trailing edge due to high speed flutter”. I have posted an analysis tentatively showing the flaperon would rotate immediately after losing the trailing edge, for any reason. In separating in consequent overload, having rotated from the neutral, that again would be inconsistent with the ATSB conclusion above, leaving no explanation at all. Putting my analysis aside though and assuming that the Silk Air 737 experience is relevant to the 777, being of like configuration, MH370 would exceed its flutter boundary only with a pilot active.

“It is well documented (e.g., Flt 006) that large and small pieces of aircraft can and do separate in-flight when the speed and/or G forces exceed the normal envelope.” The pieces separating outside the envelope in both China Airways flight 006 and Silk Air flight 185 were flight controls such as ailerons and elevators (and in the Silk Air case, parts of the horizontal tail, presumably at a divergent speed/Mach or stimulated by elevators flutter), not lifting surfaces like the flaperon and flaps.

As to susceptibility to overload without flutter, would you not expect the flaperon and flaps to be designed to resist high cantilever loads in normal flight when fully extended? If so, the structure and attachments would require much higher strength than control surfaces. That is why I would expect them to be much more robust in resisting overload, to the point that the wing would fail before them when in neutral/retracted positions.

“The evidence strongly suggests that the flaperon and right flap segment separated in flight, regardless of the cause details.”
I am unsure that the evidence is so strong. If you mean the simulations, they assumed there was no pilot and in some cases they went beyond the simulator data base.

I would have expected Boeing to have advised the ATSB comprehensively on all this. If there is a persuasive case for saying that the flaperon and flap could only have separated from flutter or high g, would that not have have been apparent long since? Likewise were a long glide ruled out, would not the ATSB have made that clear?

“…. the flight ended close to the 7th arc, and that is what is really important going forward now.” Yes, concentrate on the main game. But do so without lifting hopes falsely, which has been a tendency. This started with Victor’s observation to you, “We need to also set realistic expectations about the probability for success of any one area, which has not been done in the past”.



ventus45 says:
August 7, 2017 at 7:00 am

@David

Regarding the flap, have you any thoughts on the failure mode of the flap track / pivot fixture, which seems to have gone “missing” in all the recent photos and discussion.




Ge Rijn says:
August 7, 2017 at 7:23 am

@David

Think you made a clear summary of the arguments on the possible reasons against flutter/in flight seperation for failure and damage regarding the flaperon and outboard flap section.

Would like to add again it’s not only the flaperon and outboard flap section that are very hard to explain this way.
There are also the left and right wing flaperon closing panels, the left outboard flap trailing edge piece, the right wing aileron trailing edge piece, the left and right wing flap fairing pieces and the nose gear door piece.
All seperated in flight due to flutter and/or other forces? While in Silk Air 737 and ChinaAir 747 none of those pieces seperated in flight during very high dive speeds and/or tremendous pull-out loads (both piloted)?

Why keep holding on so one-sighted to this explanation when a ditch-like low AoA, relatively low speed, ~level impact on the water surface could explain the kind of found debris, their damage, failures and seperations much easier?

I repaet again; the danger with this conviction is it excludes areas not that close to the 7th arc.
And I rather see Ocean Infinity not make this same mistake again.



Ge Rijn says:
August 7, 2017 at 7:58 am

@Ventus45

While I was writing already I like to state my view on your question to @David also. I’m sure @David will give his opinion also (I hope so anyway).
I think it’s an important issue not well explained in the ATSB-report on the outboard flap section imo (among other damage issues).

The ATSB-report mentions a deep dent in the middle of a stiffener under this rail-track on the underside of the flap (see report-photos). They regard this as evidence the outboard flap must have been retracted.
The stiffener above the rail-track also shows some damge but not in the middle and less severe.

I think the sequence must have been something like this:
The outboard flap was hit by a sudden (series) of great impact force(s) on the underside. This force(s) forced the flap to move violently upwards causing the track hitting the underside stiffener with great force causing the deep dent in the middle of the stiffener.

Which in sequence forced the flap track/pivot fixture to break off leaving the the rail-track moving free for a while causing damage to the upper-stiffener and its surroundings.
Shortly after was pulled through the leading edge completely with its flap track/pivot fixture when the flap section seperated from the plane.

The only (series of) forces I can think of (again) are water forces hitting the underside of the flap during a ditch-like entry into the water surface.



ventus45 says:
August 7, 2017 at 8:12 am

@Ge Rijn

“I think it’s an important issue not well explained in the ATSB-report on the outboard flap section imo (among other damage issues).”

Agree, that’s why I raised it again. As a major “metal” component, the metalurgy analysis of it’s fracture (which is a well known science, and could be critically peer reviewed,by many qualified people – if it is ever produced) would be telling. It is disconcerting that there has been no official mention of anything concerning that component, which, my suspicious mind, finds very suspicious.

Thank you for your insights on the matter. We await David’s reply.




Ge Rijn says:
August 7, 2017 at 8:47 am

@Ventus45

To me it’s a bit suspicious the ATSB-report on the outboard flap section only mentions in more detail the damage that supports the assumption the outboard flap was retracted and thus it supports the pre-assumptions their search effort was mainly based on: an unpiloted high speed dive near the 7th arc. Everything else is left out. While imo their are so many clear indications on that flap section (and many other parts) that indicate it could not have been a high speed dive impact.

I’m sure willing to believe the outboard flap was retracted on seperation with their explanation but leaving all other damage unexplained/not published and thus making the public believe only the conclusions their search was based on are valid, sure loads them with the suspicion of confirmation-biased research and covering up.

Their assumptions failed. They did not find the plane with those.
I hope our suspicion is not well-placed based on reality.
But still the detailed forensic reports on debris are not available.




Don Thompson says:
August 7, 2017 at 6:03 pm

@Ge Rijn, Ventus45

Everything else is left out.

Yeah, ATSB’s report didn’t even mention black holes & aliens. Whooda thunk they’d be so remiss?

¯\_(ツ)_/¯




ventus45 says:
Your comment is awaiting moderation.
August 7, 2017 at 6:51 pm

@Don

Love the “birdie”, but sarcasm aside, I think you would be ill advised to be so trusting of the ATSB, and being so dismissive of those of us who aren’t, simply isn’t going to be productive.

The ATSB has a well documented track record of not mentioning many things relevant to an investigation. Quite obviously you are not familiar with the case of the Westwind ditching off Norfolk Island. I most strongly recomend that you do some research on the matter.

I appreciate that you are not a “local”, and quite naturally I suppose, are prepared to take the ATSB’s offerings “at face value”, ie, as, shall we say, ” wholesome”.

I am not going to labour the point, but those of us who are “locals”, do not. We have long experience of many sub-standard reports from the ATSB, one in particular, that is still “outstanding”, from 2009. That is eight years and counting Don.

I most respectfully suggest, that you would be well advised, to download and study this REPORT from the Australian Senate, and digest the misgivings contained therein.

Some other relevant links.
https://www.crikey.com.au/2014/12/05/pel...o-to-whoa/
http://australianaviation.com.au/2014/12...stigation/
http://vocasupport.com/senate-inquiries/...al-report/
https://www.atsb.gov.au/publications/inv...-2009-072/