Attempting to answer some questions A37575 actually asked;
"The very nature of the brakes coming on at the moment of touch down means heat build up in the brakes. Surely this is undesirable?"
Yes heat will build up in the brakes of course, however this is always going to happen when you apply the brakes manual or automatic and is planned for in the manufacturing process. Most airlines will have some sort of SOP regarding the use of A/B in conjunction with brake cooling times. I land the majority of the time with a/b 3, FL40 as I tend to land on short runways. With this set-up brake cooling is not an issue for our 25 min turn-around. Obviously a/b setting can be altered if needed and that is pilots discretion so long as you prove you can stop before the end of the runway!!!
"But why use autobrakes when they are simply not operationally needed? Lazy habits, maybe?"
Autobrakes can be disconnected at anytime by pilot input and so if after touchdown you so desire to do so - then fair enough. I find I tend to d/c them around 90kts (as another poster has already said) to modulate for the best exit. However I personally feel it is prudent to have them armed. If they are there and can/do help - why not use them!? Better to have them armed to MAX and d/c them on touchdown than not have them armed and forget to brake manually....
