Re: Critical engine on 747
I cannot remember seeing it the manuals, but I heard from a sim instructor that the 747 with Rollers have a critical engine, because they are triple-spool. Because of the turning moment they generate, the rudder required is not the same if number 1 or 4 is lost, hence either # 1 or 4 lost means lower Vmcg/Vmca.
Don't ask me which of 1 or 4, I have forgot.