Not Ready
To abandon ice in Fuel. I have not been 100% comfortable with what water levels in Fuel infer re: AAIB "less than significant" findings. Debating the Authority from a distance with perhaps 1% the information they possess has been frustrating, to say the least.
What the discussion has suggested to me is a different direction; without the data necessary to support it, I'm envisioning a theory that is at least compelling to me.
"contamination" can involve other than chemical or foreign substance intrusion in the Fuel supplied.
Fuel can also be contaminated by SOUND.
Fuel can be contaminated by TEMPERATURE.
Fuel can be contaminated by VIBRATION.
It seems to me that introducing ENERGY into a liquid system can create all manner of mischief. (Witness Cavitation, Foaming, Vaporisation)
Out of my field (by light years), I will suggest that I have seen gasoline "foam" at 1 atm. pressure simply by being subjected to vibration. The corollary, and of the most interest here, would be, given the VERY low temps involved (The lowest flying that day, arguably), what would it take to solidify very cold Fuel? What combination of factors can be entertained that would explain "Bubbling", "Congealing", "Waxing", etc. of tested Fuel?
1. Stasis at descent is demonstrated.
2. Sudden introduction of Massive energy into a balanced system
3. New (Commanded) Thrust level presents dozens of instant challenges to very cold Fuel, not the least of which is acceleration in the lines of the liquid fuel, reducing pressure.
4. Although snubbed against vibration and sound, Fuel passages create several local and isolated environments, each of which must react in its own way to intense vibration (mechanical) and harmonics (Acoustic) while containing extremely frigid Fuel, which has differing resistance of its own to the new "impacts".
5. Flutter. The ancient enemy of powered flight. Any articulating mass in a fluid medium can perform badly at certain levels of tuned energy. This would include, but not be limited to: Fans, Turbines, Pumps, Valves, Filters, Solenoids, and Fuel.
Holding, Airfoil