by Saratoga » Wed Mar 02, 2005 7:20 pm
Ok well lemme address some things from a pilot's perspective.
I ain't a big fan of autobrake myself, I much prefer manually braking it just for the wear savings (and maybe more challenge).
When it is used, Autobrake 1 is used on a long dry runway where you are in no rush to exit.
Autobrake 2 is for the long but not huge runways or a quick exit.
Autobrake 3 is for bad conditions, VERY short runway or heavy load, most pilots manually do it at this stage though.
Autobrake MAX is only used in the most dire situations, bad landings where you touch down hard or what not. It does not slam the nosegear down, in most airplanes autobrakes actually don't kick in until the nosegear is down. You risk, especially on older airplanes, damaging the tires or the brakes if you use the Autobrake MAX setting.
RTO applies maximum sustainable brake power if the power is retarded to idle after takeoff power is attained. This will under most conditions blow the tires, but the brakes are normally still in good condition (for airplane brakes anyways) after it is all over.
Most airline pilots I know (myself included) immediately stomp on the brakes if something goes wrong, just a natural reaction we learned in smaller planes. In the Boeing jets, if the pilot applies any brakes during the takeoff roll the RTO setting automatically kicks to the OFF setting. Which works for us, we can apply more brake pressure and can vary it as necessary (if the airplane is stopped using the RTO setting, it is extremely uncomfortable, like slamming the brakes on in a car or throwing into first doing like 80 in a manual, you get tossed all over the place).
Hope it helps.
Pilot for a major US airline certified in the: EMB-120, CRJ, 727, 737, 757, 767, and A-320 and military, T-38, C-130, C-141, and C-5 along with misc. other small airplanes. Any questions, I'm here for you.