"Icing" in valves theory
1. How much water would be needed to allow enough "icing" to develop in each of the relevant valves (mentioned by Top Bunk) sufficient to restrict them?
2. Is this really realistic given that the AAIB reported that there was no significant quantity of water in the main tanks?
3. If true, would the recognition of "icing" conditions in a turbulent fuel flow in or near these valves open up a Pandora's box, namely the much discounted possibility of ice forming elsewhere in the fuel supply system (eg at other valves or scavenge pump discharge outlets in the tanks)?