From OverRun's comments in another thread:
This started me thinking about the original question by Prof2MDA on runway width. Taking the design? normal? engine failure case on takeoff where Vef is just above true Vmcg. The aircraft will probably have wandered slightly off centreline during takeoff anyway; I don't have the relevant research to hand, but from memory a normal aircraft wander could be up to say 5m off centreline. Then given a wheeltrack (distance between the outer tyres of the outer main gears of approximately 12.6m for a 747-400, this places the outer tyres at (12.6/2 + 5=) 11.3m off centreline. Then have an engine failure just above Vmcg and experience a parallel path departure of 9m allowed in the regs, and the outer wheels are now (11.3 + 9 =) 20.3m off centreline. If the minimum clearance between the outer tyre and the edge of the runway was set to be 1.5m (my estimate to allow for load spreading in the lower pavement), then that is equivalent to a minimum runway width of (20.3+1.5)*2 = 43.6m. Hmm - doesn’t leave much fat in a 45m wide runway.
I did some work regarding 737-300 and 800 for 2m initial offset from centreline. Regulations allow 9.14 m deviation after engine failure above Vmcg. In case of 737-300, after an engine failure, the distance between outer edges of outer tyres and runway edge becomes 0.655 m, and engine CL goes 0.966 m out of runway. These figures become 0.36 m and 0.966 m respectively for 737-800 case. I am now confused about 737 operations on narrow runways and especially on such runways without paved shoulders. What if initial offset is 3 m? Note: I am not a pilot... Any pilot opinion?