Would Icing Inhibitor Have Prevented 777 Crash?
Fuel starvation caused by accumulated ice crystals was apparently responsible for the engine power loss on British Airways Boeing 777 G-YMMM, according to an interim report issued by the UK’s Air Accidents Investigation Branch. The power loss and subsequent nonfatal crash occurred on G-YMMM’s approach to Heathrow on January 17. Unfortunately, the AAIB only has one preflight maintenance recommendation so far, adding fuel system icing inhibitor (FSII) to fuel tanks to lower the water-freezing temperature to -40 degrees F. According to the AAIB, this remedy reduced similar problems on U.S. Air Force B-52s; FSII is approved for use on the 777. Still, this tactic will only reduce the risk of ice crystals forming. During G-YMMM’s flight from Beijing to London, the fuel temperature dropped as low as -29 degrees F and total air temperature -49 degrees F. The AAIB wants the FAA and EASA to see if such fuel blockages are an issue for other airframe/engine combinations, and for certification requirements to ensure that fuel systems can cope with ice buildups and sudden release.