Thanks Ed Sett I feel reassured that all senarios have been looked into. However I do feel that the QinetiQ report on the hot air system that recommends a temperature sensor or the cross-feed pipe, because the in-flight temp is unknown should not be ignored.
QinetiQ and BAE are I am sure very aware of the consequences should the worst happen again, but it appears that once again the RAF are reverting baclk to their cavalier we know best attitude which I find very disturbing.
I am no flight engineer but I am aware of the transfer of heat though conduction, the cross feed valves may be switched off and secured as you say but heat can be conducted along this pipe though the hot air system.
If QinetiQ are saying that the inflight temperature is unkown then it is unknown.
If the the RAF has carried out their own research and are 100% sure of the temp then perhaps they should inform QinetiQ if not then they should follow the expert advice that Ainsworth ensures the families the RAF is doing.