α prot = α max

[zonnair]

Hey there,

The airbus in normal law:
At take off, alpha prot. is equal to alpha max for 5 seconds.

The only possible answer I can come up with is that (A320) these 5 seconds are for the transition form ground mode (direct law) to flight mode (normal law). Studying the A330 now, I have learned that this transition takes at least 10 seconds (pitch law), meaning that my above possible answer is not valid here.

Any comments will be appreciated.

[zonnair]

Anyone, with the knowledge???

[CONF iture]

So much happening in the very early and late stages of each flight but minimum detail in the documentation.
You may have some more by directly questioning Airbus through your operation department ...

[ALK A343]

The diagram in FCOM 1.27.20 page 1 for the A330 indicates the transition period from ground mode to flight mode in normal law as 5 seconds.
However I am not current on the A330 anymore and maybe there is a newer revision than the one I have.
As said earlier the best thing would be to contact the manufacturer.

[6f1]

Yes that is correct alpha prot =alpha max for 5 secs for the A330 Fcom1-27-20 pg 4.
White mans magic I think !!!

[Bula]

With Alpha-Floor engaging sometime between Alpha Prot and Alpha Max, I dare say if they didn't keep those figures the same for 5 seconds there would be a few people conducting max rate takeoffs.

Considering it is only V2 that has to be 1.13 VS.

Vr's only requirements are that Vr is > 1.05 Vmca and it also allows V2 to be reached by 35 feet.

[zonnair]

Thanks CONF iture:
I was thinking of that too. They might come with a possible answer.

ALK A343 and 6f1:
That are most probably old fcoms then (or 320). According to the table in my FCOM. The transition from ground to flight mode takes 8 seconds for pitch law, which will start after the 2 seconds transition in lateral law.

I'll post Airbus answer.