Flightman, you seem to have inside information (?). If the descent was continuous, even in the hold at Lambourne, was it steep enough to avoid significant spool-up when they were not slowing down?
Quote (#66):
What we do not yet know is: what happened earlier during the descent and approach? Could the demand for more thrust at T+0 have been the first since top-of-descent? On a daytime arrival into LHR, that would be (sadly) a very rare event. So, assuming thrust above idle was needed earlier (e.g., on initial approach, or to stabilise at 160 kts till 4 miles for ATC spacing) how did the engines respond to the autothrottle demands?
If the engines had gradually been contaminated with dirty or waxed fuel, would this not have been revealed earlier? Why did the two engines suffer no apparent problems until 600 ft, and then - despite feeding from separate tanks - only 8 seconds apart?
Unquote.
Also, would the increased TAT and SAT in at least 20 minutes of the descent not have de-waxed the fuel, as has previously been suggested?