CONF iture
The bulletin does not say a lot more than what i posted.
Sorry for the ref to my post, it was on a early but different thread about BA38.
Here is what I wrote. (I have to put it in the right timely context though: It was only three days after the accident, well before the AAIB report this thread refers to.)
If i go about the RR Trents on the T7, there is a possibility of no malfunction but still having the effect described. The engine anti-ice is mostly switched to "AUTO". I have witnessed its reluctance to go to "ON" more than once. Lets assume the inlet PT probe was iced up, apparently a ice warning was out that day and prolonged holding in the FL80 to 120 is a ice prone region. As the EEC uses EPR as parameter for thrust setting, in conjunction with the thrust lever angle, a demand either by the auto throttle or the pilots might have been ignored by the EEC, simply because with a PT inlet iced up and PT outlet not, the difference would fake "differential pressure", thus thrust, to the EEC. It would say "I am already giving you what you're asking for", not increasing FF and the result would be the low thrust setting persisting with a functioning and happy EEC.
Far fetched?