Although nonstandarn three engine ferries were performed on the DC8/B707-747/and the coronado(ask Spantax)..Nonstandard in that the COA validity was suspect.I did 5 in 10 years on the 8,just to move the aircraft for engine changes....Several restrictions applied,reduced flap(higher speeds for 2 eng'VMC)reduced weight,240000,instead of the gross 352000..Takeoff thrust on the assymetric engine had to set by VR,and Captains were required to 'demonstrate' the proc' n the regulars Sim's.Eventually the procedure was 'phased' out,with the distribution of engines through the network..
Some 'charter' carriers were known to'idle' #3 in cruise to avoid unnescessary fuel stops...
