CRFI
Medium Salsa,
I think you've got the right idea now. Runway = 4000 ft, 70% factor (if you require it) is adjusted landing weight for a full stop in 2800 ft with brakes only. This is your dispatch limitation. There is no legal need to consult the CRFI chart for penalties until you are within range of the destination and have access to the latest RSC and/or CRFI since much work can be done and much can change while enroute. Then apply your new CRFI value to the full 4000 ft to avoid double factoring. Common sense would dictate that you consult these charts to see what you are getting into before departure. We all know that 100% compacted snow at 9:00 will be 100% compacted snow in March.
I see now that you were asking about alternates, which I believe work the same way. I would be more picky about alternate conditions since this may be where you end up if things are too unreasonable at destination. It might be worth a few hundred more pounds of fuel to get an into wind runway or less crosswind or continuous snow clearing.
If you did end up with a runway excursion, rest assured your company and TC would arm themselves with TAF's, METARS, CRFI's etc to show you why you were to blame. So if conditions become uncomfortable for you, you can arm yourself with these same things to explain a no-op day.
I learned about this stuff after I started to fly up here, so I knew what could be done safely, but it has certainly made no go decisions easier when the charts are my ammunition. The problem in the north is that following the books to the letter would be devastating to an operation, so I have developed a comfort zone based on experience and learning from others, (and the odd scare) and I use the books as my defence when the comfort is compromized. Remember, you can still scare yourself by following the books without using "common" or "bush" sense.
Lastly, two of the turboprops I've flown have a note in the AFM saying 20Kts demonstrated crosswind not limiting, others are less clear.
Bye for now, I am returning for another work week up north with 40 watt bulbs for runway lights.
Planett.