Dont' get me wrong, guys. I'm not in any way advocating throwing V1 out the window.
What I AM saying, however, is recognize that every takeoff is different than any other. Many carriers have the "Optional V1" procedure that, when an unbalanced situation exists, allows the PIC some latitude in selecting a V1 that is best suited to THIS takeoff. OK so far?
Now, if there is a microburst threat, most companies also have an "increased Vr" procedure that also addresses the excess runway to give a higher Vr and V2 speed. OK again?
Also, many cariers used an improved climb procedure that moves the V1 (and other V speeds) way up there. Still OK?
So the concept of adjusting V speeds for various reasons to fit the situation is not heresy!
Now, who here can say with certainty that in a split second after hearing/feeling a loud BANG, or shudder, etc., that the aircraft will indeed fly (and fly safely enough to be controlled)?
Mutt, in the situation I'm talking about, you have already given me the data to know that at 350,000 that my aircraft will stop/go at V1 of (let's say) 150 KIAS. If the data is correct, it will certainly stop/go at 150 if I'm 100,000 lighter than that, right? Now if my balanced field V1 is 120 in that situation, and my (much heavier) V1 is 150, there is some room for leeway.
Now, I'm not talking about a situation where you de-rate all the way down to make yourself runway limited. Then, of course, stick with the numbers. I'm only allowed a 10% thrust reduction, and even with max reduction, I've got LOTS of extra runway in many cases.
All my takeoff briefs talk about "We're right up against the MTOW on this slippery runway, so I'm only going to abort near V1 for the most critcal of reasons", or "We're 90,000 under the runway limit, so an abort right up to V1 should present no major problems," etc.
The V1 data presented to many of us flying older equipment makes NO adjustments of any kind for icy or wet situations. The same MTOW is used. That makes the data suspect for real world use. Should I not recognize this and talk it over with my crew beforehand? Or would some suggest I just use the published V1 no matter what?