Rubik & VR-HFX,
I have flown a large number of modern state of the art wide bodies and ALSO some jurrasic narrowbodies.We must remember here that these modern jets are designed to calculate the MINIMUM thrust setting required for the actual aircraft weight,field conditions(length,condition etc),enviornmental conditions etc etc.This MINIMUM thrust setting gives u V speeds for that PARTICULAR field,assuming that THAT field is now a balance field.These are near optimum speeds.Therefore,with correct data entered u will have a V1 speed with just enough runway left to stop should u decide to stop.Same again for all weights.So a miscalculation of say 100T would NOT dramatically affect the V speeds rather would affect the thrust setting to a MUCH greater degree.Cause u simply wouldnt rachieve the calculated V1 by the determined point as per the computers.Only option would be apply max available thrust or TOGA.Now here's what i wonder.I wonder if application or TOGA would give him the absolute maximum thrust or the maximum derated thrust.And then how does one get absolute max thrust in a case like this.
Well,just to make my point,therefore this concept of 'ballpark' V1 speeds just wont work in a modern airplane like say the A345 or for that matter a 777 too.The speeds for say 350T would be very close to those for 250T for the same runway and conditions.The thrust setting however would change dramatically.Which is exactly what happened in MEL.
Like I say,
My 2 cents worth