Flight Detent
I can't remember where I read this...but, I think it's in the Airbus publication "Getting to Grips with Aircraft Performance".
In any event, it is not correct that the stopping capabilities of the brakes increases with temperature. Airbus also has a publication that explains carbon brakes.
"Wear" is a totally different matter, however. Specific temps for wear rates vary slightly, depending on the vendor (and their engineers, the brake design, etc.), and wear rates improve when the brakes are a little warm.
The 300 degree limitation is for wheel well fires. Airbus design circumvented the need for wheel well fire detection.
It is interesting that Boeing does not believe carbon brakes are appropriate for the 737...but they are looking at using carbon brakes for the new 737 design. (I read this in Aviation Week and Space TEchnology.)
According to Boeing, carbon brakes offer significant advantages...like weight savings...stopping capabilities...etc. But, carbon brakes get hot...and for planes like the A320 or 737, where short ground times are sometimes part of the airline's marketing plan, carbon brakes may not have the cooling times they need for the next takeoff.
Airbus solved this problem with the installation of fans....albeit fans are an option, not standard equipment....most 320's have fans installed. (Buying a 320 without brakes fans is possible, but that's like buying a Cadillac without air conditioning....they normally come with air conditioning.)
So, while the use of fans may be optional (under your airline's SOP), they should be used as per the Airbus SOP or recommendations. And, remember, the temps keep climbing while you're at the gate...peaking around 25 or 30 minutes after the landing.
So, waiting five minutes or so after landing (or just prior to gate arrival) to turn on the fans (as per Airbus recommendation) is a prudent course of action. Depending on the turn time, you still may have the fans running during the next taxi out...turning them off just prior to takeoff.
Fly Safe,
PantLoad