The maximum distance from alternate is determined solely based on One-Engine-Inoperative (OEI) Cruising Speed over time (OEI speed x 2 h = maximum distance). Compare also CAT.OP.MPA.130 for CAT operations and the associated GM1 CAT.OP.MPA.140(c).

Dear Pablo,
It specifies the “distance” which is based on the OEI “cruise speed” in “still air” & “standard conditions”. It always remains the same. This is a “fixed” circle distance & will always be the same for alternate airport determination (ie. NOT affected by other performance considerations).
Hope this helps!
Stanko

In our operation we specify a one engine inoperative (threshold distance) (old term but very understandable) in were we incorporate all the factors above. Specifically we define an average profile for the scenario of a take-off alternate (icing, etc.). This profile is aircraft specific and included as a fixed distance in our planning system (Jetplanner). It includes a specific conservatism. I agree with Stankos post above.

Hi, Guys. It is really interesting how on a small requirement we can find such different or "Alternate Methods of Compliance", don't you think? On Annex ¨6, Parti 1, they state about ISA and Flight Time (not distance), but actually I personally and technically prefer the Dominic approach. To consider the "real" or "expected" scenario and conditions. What do you think, guys?

Hello Colleagues,

In the end - it may be a question of what your local Authority insists on. The Regulation does not require these adjustments...
Stanko

Excelente, Mr. Misetic. I fully agree with you. Another interesting point of view is to wonder Why and When this requirement was created. At least from 60’s so far. So, maybe an Operator Best Pratice and a future update of the requirement.

I guess it depends on how you look at it: this requirement just defines “how far” an alternate can be - Operators are still required to do precise performance calculations for actually going to the alternate.