alternate airport weather?

[sleddriver71]

Under part 135, once you have determined that you need to declare an alternate airport, I have a couple of questions. Can you always use the 200 and 1/2 or 400 and 1 rule to determine if the weather is good enough to use said airport as your alternate? Or, are there times when you have to use the 'FOR FILING AS ALTERNATE' minima listed on the planview page of a Jepp plate? Is the 600-2 and 800-2 only for part 91? I'm pretty sure I use to know this but I haven't had to apply it in so long, I honestly can't remember.

 

[pilotyip]

Depends upon if your carrier has the op specs, almost every carrier has the op spec allowing air carrier to determine their own alt mins using the 200 -1/2 or 400-1 rules

 

[sleddriver71]

Depends upon if your carrier has the op specs, almost every carrier has the op spec allowing air carrier to determine their own alt mins using the 200 -1/2 or 400-1 rules

One of the reasons I asked the question is because sometimes the 800-2 will qualify the airport for use as an alternate when using the 400-1 will not. At the same airport which only qualifies as a 400 and 1 (if the ops specs allow it)(in this case an airport that has only one approach and circling minimums of 500-1 for category A and B), you cannot use it as an alternate using the 400-1 if the forcast indicates, at the time of arrival at the alternate that the weather will be 800-2(need 900-2 using that method) but using the 800-2 method, it obviously qualifies. So I guess I should have asked, "Can you use this method to allow you to use this airport as an alternate even though your ops specs specify the 400-1 rule?"

 

[pilotyip]

The answer is no

One of the reasons I asked the question is because sometimes the 800-2 will qualify the airport for use as an alternate when using the 400-1 will not. At the same airport which only qualifies as a 400 and 1 (if the ops specs allow it)(in this case an airport that has only one approach and circling minimums of 500-1 for category A and B), you cannot use it as an alternate using the 400-1 if the forcast indicates, at the time of arrival at the alternate that the weather will be 800-2(need 900-2 using that method) but using the 800-2 method, it obviously qualifies. So I guess I should have asked, "Can you use this method to allow you to use this airport as an alternate even though your ops specs specify the 400-1 rule?"

If a 135 rule or op specs are more restrictive than the part 91 rules, you must use the 135 or op spec as a guide if revenue is on board. If is is a 91 leg, non-revenue you could legally use part 91 guidlelines.

 

[Doc Holiday]

If you look at the opspec, there are three conditions in paragraph b. The first one states that the certificate holder CANNOT use any other alternate minimums than the minimums derived from the table below. Referring to your example above, you must use the alternate minimums derived from the opspecs, or 900-2.

Hope this helps.