Calling V1 early

[john_tullamarine]

.. no more leave for OS .. he instantly goes into punny mode ...

I’m much more comfortable when V1 is a little above Vmcg

This is a point which we try to keep in the line pilot fraternity's mind. Because the very great majority of us don't get to play around at Vmcg with a failure, there is a tendency for pilots to fall into the trap of believing that the bird will always behave like it is "on rails". This is made worse by the problem with poor fidelity in some/many simulators.

In the real world, the onset of directional problems typically can be very sudden in terms of heading/centreline deviation as a function of failure IAS - for the continued takeoff - generally the accel-stop is not such a problem.

It really is a case of now you get away with it ... now you roll yourself up into a ball on the grass. We might be talking here in terms of needing only a few knots to go from relatively easily controlled to runway side departure and once we get onto that roller coaster, it is only a few knots to make the departure one which could be described as exciting ...

In the loss of control case the mental workload associated with the pilot's having to assess the problem and then, while the aircraft is pirouetting off the side of the runway, having to close the throttles to get some control back (if you are lucky) is a big ask .. remember this is the guy who is primed up to GO !! and it just isn't working out the way he expected to see it happen.

The problem I see is that the very great majority of pilots have NEVER seen the problem and have a tendency to under-rate the significance of a Vmcg-limited continued takeoff. It is for this reason that, for sim endorsement training, I always exposed the crews to min speed/weight, aft CG failures (unless the particular sim was dreadfully unrealistic).

As an aside, there is one thing in the pilot's favour .. while the weight may be low and the speed schedule at minimum, normally one isn't going to see CG at the aft limit as well and the effect of CG on Vmcg (real world as opposed to certification) is significant. But, if the holes all line up, then beware.

.. perhaps we should talk about crosswind effect on Vmcg again .. ?

I have taken the liberty of blanking out several words in OS' post to protect my identity a little .. talk about putting my name in defacto lights ...