Carbon brakes, use and misuse

[Right Way Up]

Ref turning on brake fans during turnround. Its not difficult, just get the PNF to give a thumbs up during the walkround that the no-one is in the vicinity & fire them up.

[Dream Land]

let the brakes cool ''naturally'' at the gate during turnaround

That's a good one, where I work the first thing the engineers do is push the brake fan PB, lol.

[Fil]

We have 9 or so older A320's without brake fans, and a good number of new A319/320/321's all with fans. When the decision was taken to purchase the 31's (last to come) the engineering input was the 320's WITH fans had a lower brake wear than those WITHOUT and that the extra cost of the fans would be reclaimed over time due lower brake wear.

On regular LHR-MAN's during summer time you can find it hard to keep the temps low due short turnarounds.

[420]

quick turn arounds.

i agree that turning on the break fans at the gate will cause lots of unwanted sharp and painful noise (like nails on a chalkboard).But then again, for airlines with short turn arounds throughout the day,i would think that this is a necessary discomfort. after landing with autobrakes low and full reverses,exiting a high speed taxiway followed by taxiing to a bay approx 7 mins away with turns which of course require further gentle break usage,by the time u hit the parking bay,one will have to switch it on. not to mention in hot climates. i would think the temps would be around an average of 250++ by then. so if we were to leave the fans off during quick turnarounds,it should go down to (if the temp DOES reduce in the first place) to about 220? and after pushing back and the ramp guys clear out you switch on the break fans,sure there would be ample time for the brakes to cool....but u still got to taxi to the runway...with the same 7 minute taxi with the extra load and fuel now and with the same OAT and not to mention...a 220 C on the brakes. so yeah the fans are on...., but its being used at the same time. i doubt it'll reduce to 100 C or below before T/O. and i know the limitations for airbus is 150 with fans off...but hey,dont think id risk it with an RTO.

dont know about u guys.

[Mach trim]

RTO

Good point I like to get the temp down to at least 60 degrees ( my target ) before turning brake fans off in case of RTO

[PantLoad]

SOP

The Airbus FCOM SOP for all of this is correct, proper, minimizes environmental problems, maximizes brake wear and efficiency, etc., etc.

My advice is to simply follow the Airbus FCOM...unless your company's SOP differs...then, of course, you are obligated to follow that, instead.

PantLoad

[fruitloop]

Mach trim
The reason that "I" would prefer to have crews turn the fans on BEFORE entering the ramp area is as you mentioned that on Initial start up a "mist" of brake-dust which can be seen(carbon which isn't really healthy for any-one being of a cumulative nature)and the "gassing" from the Lithium grease when it reaches a "certain" temperature (invisible but smelt)(wheel bearings) that always seems to happen to me when setting up the fuel panel.Added to this any lubricants that have made their way (gravity with assistance from condensation)to the brake area (including landing gear grease,spilt strut fluid,corrosion inhibitors etc etc)which all add up to "interesting smells" being blown around.

[slf911]

What is max allowable brake temperature?

As a non pilot and a watcher of formula one racing, I have seen discs on cars get red hot and wondered what is the temperature at which carbon brakes start to fail? Appreciate you would not want to get anywhere near this other than in RTO.