As a fuel guy, do you conclude that the (permitted) water was the culprit? Was it an accumulation of atmospheric moisture via venting? What about the conclusion that the ice was 'soft' and 'malleable'.
Also, Pinkman, what of Boeing's 60 years experience of turbo (fan) jet performance at levels up to 60k and above? It remains disconcerting to me, probably to others that the industry seems to be a bit coy with the purported 'mystery' of this event.
What about the 'slurry' theory from Airfoilmod? Some combination of waxy fuel and microcrystalline water-ice? Have you seen this before?
Tough questions. I don't have an answer for all of them. All I can tell you is what I think which is:
- I think that the dissolved water is a complete red herring. Free water, eg from fuel stratification, may not be. And if that came from the free water then maybe the free water is an issue after all.
- I don't think industry is being coy: they just dont know what is going on.
- I think airfoilmod is very close. I believe it was a unique situation related to the distillation properties of the fuel such that it met all the ASTM tests but didnt perform as conventional fuel under those unusual circumstances. Who knows, it might be related to biofuels. Yes, I have seen distillate fuels wax up and I have seen an ice-wax emulsion.
The thing about fuels testing is that you only test for the basic properties (freeze point, smoke point, distillation range, Calorific value, etc etc) and the qualities of the things you expect to be there. In the UK we had a gasoline contamination problem a few years ago that took thousands of vehicles off the road almost overnight. The fuel met all the BS/EN228 spec tests. It took nearly a fortnight for someone to trace the fact that the fuel had been adulterated with waste electrical solvent (mostly toluene). It got the Octane rating up (its aromatic) but had silicon in it which poisoned the oxygen sensor. But it was on spec!
Another example: Chinese baby milk scandal. It contained Melamine, which tests out as a protein, but is of no nutritional value and actually harmful. But it was on spec!
The point being that you dont test for the things you dont expect to be there. Fuels are heterogeneous things that dont always do what you expect. In the short term the only way to get on top of this is to test them in the environment in which they will be used and use the information to modify the testing regime.
Pinkman