I don't have 9137 neither and generally I agree with Spitoon.
the CAA have legal right to oblige you to comply with somehting that has not been ruled?
Let's say that Spanish CAA ruled itself on the matter, so they have legal right against Spanish AOC holders.
I have seen houndreds of times people operating to airports with Fire Cat 4 or 5 with large airliners and also using them as Alt.
Wether the Flight Ops's chief authorizes such operations charging the responsability him/herself, it is possible.
P.S. Any download suggestion about doc 9137 ? Found nothing but to buy it on ICAO at £100
