Brake Temp And Autobrake

[Guest pp763]

Has anyone noticed that the brake temps do not increase on landing with the autobrake doing it's stuff. They only increase with manual braking. Can't wait for the replies.

[Guest 744nut]

Hi PP,The deceleration in landing mode of the autobrakes on MAX level is less than produced by full pedal braking while taxing or in roll mode. I think that is the reason why you got "brake temp" at taxing and not with landing.regardsTon

[Guest pp763]

Thanks for the reply, However even with Autobrake 2 on landing there should still be an increase in brake temp on the gear status Thanks again.Paul

[Guest detector]

Paul,Try autobrake 3 or 4 with a heavy load. I got a yellowish warning plus higher temp readout. Cooled down after a few mins.

[Guest 744nut]

But I assume it does not exceed 0 (=100 Celsius) let alone 9 ( =866 Celsius);-) Ton

[Captain2000 0]

Try it with RTO. Did a test stop from just below V1 and had 7's across the board on brake temps.

[Guest 744nut]

RTO is giving the full brake power so a high number is the resultTon

[cowpatz 243]

Apart from the RTO function the autobrake settings only program a rate of deceleration. In fact selecting max does not give full braking, only RTO does this. If you land and use REV thrust the brakes will ease off to maintain the programmed deceleration rate ie. 1,2,3 max etc. If you cancel the REV then the brakes will increase pressure to maintain the deceleration rate. Therefore you would expect to see a reduction in the brake temps. There is a delay in brake temp indication. They will peak out around 15 min or so after landing. Also with manual braking in the sim you dont really know how hard the brakes are being applied (probably full on each time you activate them. This will heat them up.CheersSteve

[Guest Ricardo Sevarant]

Will the autobrake system automatically prevent brake pad overheating? In other words, is there a thermal sensor that would automatically ease up on deceleration if too high a brake temperature is sensed? Perhaps the anti-skid system itself prevents overheating, I've always wondered about this.....

[cowpatz 243]

No there is nothing to prevent brake overheat. There is a brake torque limiter that is all. The wheels are equipped with fuseable plugs that will melt when the wheel temp gets too high (otherwise high and dangerous tyre pressures could exist that may cause a wheel to explode)and consequently deflate the assosciated tyre. You can expect this to happen on a RTO at high weights or rwy limting TO's. Changing 16 main wheels afterwards is not a pleasant task!Steve

[Guest Ricardo Sevarant]

Cool info, thank you.