Tina wrote in
:

B, I can appreciate the 'go mode' from some speed onward, but runway
lengths vary by some thousands of yards. With a typical load and
normal conditions, how long a runway would allow you to decide to not
go if something drastic happened at just below lift off speed (like a
door blowing open, or a windscreen failing, something like that)?




Actually, we probably wouldn't stop for something like that if we were
close to V1. The actual recommended brief from MR Boeing these days is
"We'll stop for an engine fire, an engine failure indicated by two
parameters, or anything I reckon makes the airplane unsafe to fly" The
last bit reinforces pilot discretion and allows us to make a decision
based on our assessment in a given situation. For instance, though we're
not supposed to, i did abandon for a belly cargo door unlocked light
once. I was in the high speed regime, but still relatively slow ( about
110 knots) and we were light and the runway was quite long. No big deal
and the stop was pretty much a non event. However, there's no way I
would have stopped for that if I were close to V1 and the runway was
short. Some people are already saying he put it back down aftger blowing
a tire after airborne, whihc is almost certainly complete crap. We don't
stop for tire burts in the high speed regime. Chances are you will also
burst the adjoining tires and have very poor braking afterwards.. He
might have doen this, but he'd have to be a very special class of idiot
to have done so and it probably would have been a lot worse if he had in
any case.
But the decision speed is calculated for each runway, and should allow
you to either go or stop at V1 in theory. IOW you can't take as much
weight off a short runway as a long one, just like any other airplane.
In actual fact overruns are common from high speed stops for a variety
of reasons, not the least of which is the time it takes to assess the
situation and make the decision. Usually they;re not as bad as this one,
though.
Quite possible they abandoned at a relatively high speed for whatever
reason and just didn't get on the stoppers quickly enough, or , as
someone suggested, there was a cargo shift, but that's pretty unlikely.
Time and the report will tell, but it's quite possible that the crew
will be found to have done everything correctly and they just ran out of
runway..

Bertie