Also icing, fuel contamination, a catastrophic failure of one throwing parts & causing damage to the other, interference with controls/switches, failure of one + procedures while operating on one engine resulting in failure of the other (probably not simultaneously but landing with both engines stopped doesn't necessarily imply simultaneous failure).
There's five off the top of my head + what previous posters have written. Shall we have a competition to see how many reasons can be devised?
Last edited by Tinstaafl; 25th Jan 2011 at 01:43.