Delayed rotation compromise
Hello all!
So the other day, we were taking off from a very long 4000m runway. Just before commencing the roll, we noticed many birds flying just at some height above the center of the runway. A lot of them.
And just after V1, as Rotate was called out, it became clear that if a normal rotation was done then, at the 3°/sec rate, it was certain that we would right fly through a dense bird concentration.
We decided of rotating very slowly, just to pass them still on the runway, and after that, very slowly rotating, we lifted off and were clear of them. Takeoff and climb progressed normally.
Now a question arised. Was this delayed rotation, lifting off much later than the performance calculation, outside of the minimum gradient limits?
We still had a lot of runway ahead, more than a 1/3rd when we lifted off.
My comprehension is, since we're not field limited, with our take off weight, our V1 and Vr were at those speeds just because it was more than enough. But since we were still with a long runway ahead, I cannot think why we can't delay the rotation, even if obstacles and a 2nd segment obstacle clearance limit were of concern.
As I see, as long as we lift off passing at 50ft above the clearway or the other end threshould, our second segment gradient will be obstacle free.
Am I right or missing something?
In other words, taking off from the middle of the runway or very near the end, doesn't affect obstacle clearance and 2nd segment requirements, since we are still taking off from the runway and complying with the requirements.
I would like to see your thoughts in this... In that situation it was the best decision since, better take off with all engines even delaying lift off, than to rotate precisely at the calculated speed, and face the real threat of one or even 2 engines failing.