777 Ice

[forthbridge]

Well, with yesterday's reports and this:
http://news.bbc.co.uk/1/hi/uk/7941137.stm

It looks to be certain as can be that Ice was the factor at Heathrow.

What I am curious about is given the number of hours on RR engined 777s - what reasons are there that (so far) we only know about two incidents of this 'event'? Surely with the hours on these aircraft, they must have encountered similar conditions and temperatures at other times - yet apparently without issue?

I know there's mention of 'particularly' cold air on the BA flight - but was it really that unusual? To the layman (me) - cold = possible icing, and once you're at height in winter, well, is there really much variation in temperature, or is it normally 'mild' enough that this hasn't been an issue before? It just seems quite strange...

[petermcleland]

Jim,

It was an exceptionally cold higher atmosphere that day and it just brought to light a major difference in the design of a particular filtering sytem that is unique to the RR engine...The other engine makers for that large engine route the fuel in a different way to that filter, that would prevent it happening on their engines. RR are busy re-designing to remove any possibilty of that icing fault happening. Meanwhile, various procedures have been introduced to stop the problem occuring prior to the newly designed system being fitted. :flying: