Thanks.
The Ops Manual does indeed have all the criteria you mention, and I would have thought we should use that. What the company has tried to do is produce a 'generic' PLOG for the various destinations with an alternate which is 50 miles away. My argument has always been that, provided the alternate has the weather, it can be 5 miles away, but the CP has insisted on the 50 mile rule. In practice, were the weather to be below limits at original destination to be unsuitable we would go to the nearest suitable airfield rather than necessarily the planned distant diversion. We would of course not be able to launch without the weather being right at this alternate, but it seems daft to carry fuel for somewhere 50 miles away when 5 will do.
It all seems to be leading down the road I believe to be right: You can plan for an alternate generally which is 5 miles away or whatever, and for the 1% of time that that is unsuitable you carry extra fuel and plan for the distant alternate.
I may not have expressed this very well, but I hope you get my meaning.
