I used to have no or few problems with Apple Airports, however since I upgraded the firmware to 7.6.3 a while back I have had the same re-occurring issue.
The airport stops working wirelessly and needs turned off and on again. With 42 airports this can be annoying. Two days ago when starting the wireless survey I turned all the machines off and on again. Within an hour some of the base stations had 'froze'. Today I decided to downgrade the firmware in the stations to 7.6.1 - Apple themselves are no help in this, they appear to be doing the usual apple response to issues which is ignore them.
So far out of 19 machines on the network 13 are not responding.
10.8.4 and Airport Utility was useless for downgrading as it only showed the most recent firmware (and yes I did press option while pointing at firmware). However I have been saved by an old mac running 10.6.8 and its airport utility which shows earlier versions of the firmware.
see
[size=78%]https://discussions.apple.com/thread/4787229?start=15&tstart=0[/size]