So this has no relation whatsoever to the 777 approach to LHR when the RR engines had a problem answering the throttle at a critical moment due to ice melt? How did RR sort that problem?
As others have noted, totally unrelated - the BA 777 occurred when what is referred to as 'sticky ice' (seriously, it's in the FAA training materials now) obstructed the Fuel/Oil Heat eXchanger. The FOHX was redesigned in the aftermath - acutabove is correct that they changed the way the small tubes entered the heat exchanger to discourage ice formation in that area, but the most important change was the addition of a bypass to the FOHX - if the delta pressure gets above some level (memory says ~30 psi) the bypass will open and allow the fuel to the engine.
The TV show I saw (I think it's called 'Terror in the Sky's' - it's on the Smithsonian channel in the US) got it about 75% right, then totally blew it with two 'facts'. First, they said the engines 'failed' - they didn't fail, they just didn't respond to the throttle command to accel (because the FOHX would only allowing about 4,000 lbs/hr to pass) and were still running above idle when the airplane hit the ground. Second, they showed beautiful pictures of the fuel test rig, and a diagram of the FOHX showing where the ice formed, then referred to the FOHX as the "Fuel Filter" - repeatedly
