I perfectly agree this is a planning figure.
I didn't know this figure is fixed and has to be certified.
In my company manuals it's not published, while I recall it was in another company, but on a different airplane.
Now I know it
should be published under Jarops, thanks to your input.
Re: the 10000ft in my example: I know this is too low, but I deliberately choose this figure in order to be able to accelerate as soon as possible, so to obtain the longest distance flown.
Like you, I wouldn't really care if it took one hour or something more to get to the takeoff alternate.
My concern was only to defend my selection of the alternate before a judge...
Since you tell me the
certified distance is 330 miles, fine, I'll take 330 from now on.
Good to always learn something.

LEM
Ps: the Beast in fact was asking about "... the takeoff alternate...", so no doubt he got his answer by now.