This is pure speculation from someone no longer associated with airlines, but I am afraid it may not be so easy to discard Mr. Husted's theory.
I note that the latest AAIB report says:
Data, downloaded from the Electronic Engine Controllers
(EECs) and the QAR, revealed no anomalies with the
control system operation. At the point when the right
engine began to lose thrust the data indicated that the
right engine EEC responded correctly to a reduction
in fuel flow to the right engine, followed by a similar
response from the left EEC when fuel flow to the left
engine diminished. Data also revealed that the fuel
metering valves on both engines correctly moved to then
fully open position to schedule an increase in fuel flow.
Both fuel metering units were tested and examined, and
revealed no pre-existing defects.
Posters have jumped to the conclusion that if the fuel flow increase was scheduled, then, if engine thrust did not increase, therefore the scheduled fuel flow increase did not happen. But, unless I'm missing something somewhere else,
that's not what the report says.
Absent independent data from a fuel flow sensor showing that fuel flow did not increase, then I wonder if it's possible that fuel flow
did increase, but that Mr. Husted's core icing prevented the engines from generating sufficient thrust?
If this were the case, I suspect there would be considerable egg on a lot of faces in the industry.
P.S.: In a fully flapped (40 deg) Cessna on a 3 degree approach at 500 ft, at engine idle I can't reach the end of the runway either. Please think about it before criticising the pilots.
