Originally Posted by
ismertr
From what I've found, if it is a domestic 121 flight, the standard 1,2,3 rule works to determine if an alternate is needed. Does this apply for regional airlines like Colgan or Eagle? I read some items about 1500 feet above circling mins.
And for the alternate, should the "Add 400 and 1 SM Vis if 1 Nav aid" or "Add 200 and 1/2 SM Vis if 2 Navs" be used?
Anyone have any real world experience?
All three FOM's I've worked under used this method, also referred to as OP SPEC number C55. None of the FOM's mentioned (that I remember anyway) anything about using a circling minimum to get a derived alternate minimum.
Also, the books I've worked under classified Canada/Mexico as "foreign", but we're allowed to operate in there under domestic DX rules, or something like that.
Originally Posted by
BoilerUP
You're thinking of derived minimums...just wait until you start looking at Exemption 3585; that's a whole 'nother ball of wax...
As well as when the term "marginal weather" is thrown about. Two of said FOM's had one definition of "marginal weather", my current one is different.
It's always best that when you're DX'd under 3583, or simply have 2, 3, or 4 alternates to get out the FOM and go through it with a fine tooth comb to make sure DX didn't goof up. I've had it happen to where the second alternate would have been good, except a NOTAM dealing with an inop navaid made it not. The DX'er missed it when it was used. Not slamming a DX'er here, as they can easily get overloaded in this situation, as well as being charged with dealing with 50-60+ releases per hour.