On Sep 5, 4:26 pm, "Jack )"
wrote:
On 5 Sep, 15:27, "Martin Rowley"

wrote:
it seems to a layman that this would have cropped up before - any tales from your experience on these things?

I never had any problems. Minimum outside temperatures were specified
(I can't recall the numbers now - ten years ago since I last flew.)
Although I did fly in the cold stratosphere, I was mainly on short
haul flights with rarely more than 1.30 hours in those temperatures

The report is quite technical but basically the presumption is that
blocks of ice formed between the fuel tanks and the high pressure
pumps that feed the actual engines.

There is seemingly no direct evidence for that scenario, but
simulations of blockages in the appropriate part of the fuel lines
exactly the symptoms produced experienced on that flight.

The engine automatics were trying to supply the correct fuel flow,
then it cut back with the blockage, increased again and finally the
fuel control system could no longer cope.

The engines were starved although they didn't actually cut out,
merely didn't give enough power.

It is probable that in the longer term, fuel systems in later aircraft
models will have to be redesigned (with more line heaters, etc) but in
the short term, existing aircraft might simply have to operate under
more restrictive conditions, ie limited duration in extreme cold.

One throwaway comment in the report is that this particular problem
might not be confined to Boeing 777s but many types could be
vulnerable.

With the problem occurring at just the wrong time producing the
spectacle, I assume it is a fairly frequent occurrence (statistically
speaking) at altitudes where corrections can be made.

At 7000 feet for example, you get the ability to switch tanks that
isn't available while you are still wondering: "WTF?" at 700 feet?