Thanks CliveL, your response is appreciated.
Your question is a good one, and I would like to offer that the quantitative component should have been done by BEA in the first place, after all, it is their photography.
I have offered possible approaches to glean some understanding of the affect of tyre rupture, and my suggestions have been ignored. Likewise, an attempt to quantify would be based on data supplied from BEA, data I believe is lacking in sufficiency.
It is BEA who proffered the photography, and begged the work, then did not perform it. Neglectful.
It was BEA that exonerated any complicity of the shoddy Mx by AF. Presumptuous.
It was BEA who did not provide the chemical analysis of the rubber that may have proven the Titanium had been present in the tyre's carcass. In neglecting even the attempt to prove conclusively the strip was involved, they demean the discipline itself. Lazy.
It was BEA that neglected elimination of material other than Titanium as the cause of tyre rupture, Cowcatcher/mount?
Was the area of the truck's mount inspected/analysed by BEA for abnormal wear? The landing gear had travelled several miles carrying two hundred tons, was the spacer's saddle worn?
Was the #2 tyre studiously tested for weakness, as it was two thirds through its useful life, and may have acquired weaknesses unrelated to FOD? Were the other three tyres on the left bogie scrupulously inspected for evidence of misalignment of carriage?
Has anyone found an opinion on why the Captain's rudders were not planted full right? And held?
The report can be described in many terms. Exhaustive is not one such term.
Quote:
Shimmy, as I understand it, is a cyclical rotation of the wheels about the main leg. Again at the time we are talking about, the aircraft sideslip was 3 deg. Allowing for +/- 3 deg oscillation because of the missing spacer that would mean the wheels oscillating between zero and 6 deg would it not? Why would the time they were at less than 3 deg not offset the time they were at more? Or in other words, why should shimmy change the average force?
Shimmy is analogous to a human heart in arrhythmia. A pulse of two hundred, and no blood flows, the pump is stalled. Shimmy means skid, and skid means poor traction, and irregular bite at that.
"Shimmy" makes unlikely any predictable effect of any part (cycle) of the oscillation. Therefore, because the bogie is aligned ("established") part time, one cannot then predict that the corollary alignment is of equal (balanced) force.
Note the shape of the shimmied tyre, number 1. The excursion left is broad, the return to "zero" is sharp, and shortlived. Therefore, the side load is left, and LEFT.....no balancing side load right. This demonstrates that at least in the area of the photographic evidence, the net load is constantly left. This means a bogie that is tracking well left of the longitudinal axis of the airframe.
"Shimmy" in itself does not suggest the kind of conclusion you make, some "balanced" or normed load. There is no reason to assume the shimmy was established in consistent fashion at any time, except for the three arcs of tread deposit we see. It could have been extremely irregular.
An admission. I have not found the reference to shimmy in the Report. Therefore I do not know BEA's conclusions. I'm extrapolating on evidence I see, and read elsewhere and in the BEA work.
My assumption is that BEA rejected the possibility that a missing part contributed to the crash. If they did not, and lay some responsibility on AF, that would be a welcome coincidence?
Last edited by Lyman; 18th Dec 2012 at 22:45.