Question:
Can a fighter scramble from an airbase that has a capacity that has been reduced to zero?
Answer:
No. WitD Rule 17.A (airbases, Capacity) says specifically:
“Exception: Air units may not take off from or land at an airbase if its capacity is currently zero.” SF goes so far as to say “may not use” which covers a lot of ground.
One has to be careful about remembering this provision, when getting used to the new air on demand system, where base capacity has less effect upon initiating missions from a base, since capacity is normally most important for operative/ inoperative considerations. But the rule is clear, no use, that is, taking off or landing at a base with zero capacity. This prevents multi-leg transfers and staging as well, of course.
Source:
TEM 59/60

