heathrow 777 crash confirmed cause - Ice in fuel feed

Carawaystick

as reported here
http://www.theregister.co.uk/2009/03/12/heathrow_777_update/

report here
http://www.aaib.gov.uk/cms_resources/Interim%20Report%202%20-%20%20G-YMMM.pdf

I read the first report, the ice theory seemed to be well developed and a series of events conspired to cause the issue - long time at low temp as flight was over the north pole mostly.

FlutterinBantam

My first reaction to that was that it was amazing that after hundreds of flights on that route this was the first one to display those symptoms.

It would appear that there were extreme weather conditions en route,but despite this I would wonder about some fuel contamination which could set up this scenario.

Just my opinion.

Mr Benevolent

Imagine being on short final in a heavy jet and discovering the engines won't spool up from idle :eek:

I'd probably need a new pair of pants. Apparently some pax just thought it was a heavy landing!

I was coming into Barcelona on an FR 738 one night, sitting at the window. 20 feet above the runway I suddenly noticed the sink go way up. I just though 'oh sh!t' and hung on. Bang, a nice set of divots in the runway And that probably wouldn't be classed as a heavy landing.

John_Mc

FlutterinBantam wrote: »

My first reaction to that was that it was amazing that after hundreds of flights on that route this was the first one to display those symptoms.

It would appear that there were extreme weather conditions en route,but despite this I would wonder about some fuel contamination which could set up this scenario.

Just my opinion.

They were able to test the fuel that remained in the aircraft after the incident. If it was contaminated then this would be stated in the report, and it wasn't, so your opinion is wrong on that one.

Celtic Mech

FlutterinBantam wrote: »

It would appear that there were extreme weather conditions en route,but despite this I would wonder about some fuel contamination which could set up this scenario.

Just my opinion.

As aircraft fly at high altitudes, it is inevevitable that we will get water into the fuel, hence the need to drain the water from the tanks each day/night, whichever allows. The extreme cold temps will cause condensation to build up on the inside of the tanks. This condensation buildup drips into the tanks and mixes with remaining fuel. But, as you know, Water has a higher density than fuel, hence the water is always on the bottom. It is this principle that allows it to be drained each day, or whenever it is required by the operator.
The Fuel trucks can be tested at each upload of fuel they deliver to aircraft and we can see if any water contamination with fuel is being pumped onto the aircraft.
I have read the initial reports etc. It is now saying that a new Fuel Oil Heat Exchanger is to be designed immediately and as soon as possible. Purpose of the F.O.H.E. is to allow the Engine oil system to heat up the cold fuel, thus causing any ice to melt via a heat exchanger.
At cruise across the Atlantic, the temperature of the fuel can go as low as -50 degrees C and lower! On a healthy Engine, you would be looking at oil temps at cruise of about 110-120 degrees C so you can see the massive ice melting qualities that are available via this heat exchanger system.
Just hopefully a new FOHE can be designed before any other situation like what happened can occur again

Foggy43

Strange the report was released yesterday when also a BA A320 had to 'free fall' the gear down on approach to 27L at LHR. A relay problem apparently.

I got suspicious when there was 3 go-rounds one after the other. Runway FOD check. Then spotted the A320 with gear doors down surrounded by fire trucks under the new control tower.