Originally Posted by
Tummy
Absent people getting shot at, why would you ever want to get the climb gradient waved? If it's this hard to figure out if an airport is a good alternate, and you aren't in combat (<-- might not be an accurate assumption), why would you want to work this hard to use it as an alternate?
Find somewhere else to go. Of course, I'm an aviation nerd at heart and like the discussion regarding technical specifics, but I'm reminded of the culture I used to experience in the military where we were always compromising safety for no good reason.
Because the mission depends on getting into those places and the mission justifies assuming the extra risk. You're not going to do it for some staff guy who can just as easily get in there via comm air, but if it's for a team that can't feasibly get in there because of roads or enemy territory it's a different equation. Sure it's more risky but the key is how do you mitigate that extra risk?
If you can see the terrain and you have the data to prove you can safely maneuver OEI to make a safe return is that really different or more dangerous than flying IMC on a SID? You can also use a third party like jeppesen to create custom special departure procedures that will keep you clear of terrain for your specific weight and weather conditions if your airframe has access to a program like that.
Also remember that the climb gradient assumes you lose your critical engine exactly at V1 and you cross the departure end of the runway at exactly 0' agl. So if you rotate any earlier you already have a head start on that climb gradient, not that you want to rely on that, but hey it's a warm fuzzy feeling when you definitely need all the warm and fuzzy feelings you can get.