[QUOTE=ismertr;763104]Hi. I'm studying about 121 alternate airport minimums : When an alternate needs to be filed and the minimums required for the alternate. This will be applied for a regional carrier (ie Eagle or Colgan).

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.


If you are talking for an interview, know the 123 and 6/2 and 8/2 rules.

If you are talking about actual requirements, it depends on the opspecs and the regs.

Under my 121 rules, 123 applies to the need for an alternate.

Under my previous 135 jobs, it is more complicated:
One hour before or after...
1000 above the lowest straight in min or 2000 which ever is greater
AND one mile more than the lowest vis or two miles whichever is greater

Standard alternate requirements are 6/2 or 8/2

Derived alternate mins were:
135
One suitable nav aid:
400 above the lowest CIRCLING min (or if circling is not authorized, straight in) , AND add 1 mile to the HIGHEST vis not less than 2
two independent navaids to suitable runways:
200 above the lowest CIRCLING min (or or if circling is not authorized, straight in) and add 1/2 to the HIGHEST vis not less than 1

121 is the same as 135 EXCEPT the additions are to the STRAIGHT IN mins and STRAIGHT IN vis and the NOT LESS thans do not apply

IN general, 135 rules require an alternate about 200 and1/4 ABOVE when 121 requires it. And the alternate will most of the time be based on CIRCLING mins rather than straight in.

So, just like duty/rest rules, 135 is more restrictive.

funny how that is........


In any event, your company's opspecs will set your specific limits