Brake temperatures with autobrake

[soen 11]

I did now 5 full flights with the NGX and so far everything works perfect. The only issue I observed during this flights is with the brake temperatures. On all my landings I used the autobrake setting 3, and flaps 30 or 40 and idle reverse. The strange thing now is that I never observed a change on the temperature indication. After every landing they stayed at the value 0.0. I only "achieved" to get hot higher temperatures when I used manual braking. Has anyone else made the same observation? Is this a failure or just the real behaviour? BTW i use the steel brakes

[FreightDawg 10]

land at 200knots autobrake 4 youll see a difference

[lonewulf 1]

I see the same using carbon brakes. I never have observed an increasing figure. Even prolonged taxiing with frequent brake application should give a noticeable increase but I always see 0.0. Oskar

[Lusche 3]

I have another brake temp problem ... once you overheat them slightly (4.x ?) the temp wont sink anymore, just rise ?It was listed in the failure menu for overheating, but shouldn't the temp sink if you dont use them anymore ?

[VLJ510 16]

Well there are variables but the carbon brakes won't get that hot under normal conditions and also still take time to reach the temp sensors I believe was spoken of. Also with steel brakes it will take some time reach the sensors as well as the energy has to convert to heat then move to a sensor to a max reading will not registrar off the rip. I've seen both so far over 4 and currently in 5th flight now but the steel do heat up the carbon never hit 250c or lose any real effectiveness. With the steel I also noticed the braking effectiveness drop as heat saturated the pads on landing but this takes time, at the gate they were pretty hot and effectiveness was noticeably different. I've only uses auto brakes 3 once on steel and the rest have been on 2 with carbon as I've been flying from SFO to Hawaii airports. But I have seen both brakes work along with the temp reading and the effectiveness drop as advertised, I'm not saying they spec not they have moved and reported numbers grater then 0.0. I have been doing takeoff loads with about 33 to 35,ooo lbs of fuel and 130 to 140 pax giving about 80 to 90% load. Then landing with about 4 to 5,ooo lbs left and a Vref of about 141 to 146. Maybe your just not pushing the limits of weights as the more weight you carry the more those brakes have to work to stop it. I think it was AoA video that showed brake temps maxing after 10 mins on the MD11 videos with high speed RTO. -Raven Harris

[lonewulf 1]

Hmm, well, let me tell from my RL experience with carbon brakes: they heat up considerably quick. Much quicker than steel brakes. After a landing at 50 t with Autobrake at 2 they should go up to at least 150°C if not higher. Also riding the brakes during taxiing you will have the very cuickly above 200°C Oskar

[soen 11]

Well, I had a payload of 38´000 (about 75%) and 6000lbs of fuel left during the landing in KMSY. The outside temperature was at 34C. Even after 10min on the ground the temperature was still at 0.0. I think you are refering to the MD-11 High Speed RTO Video?

I have another brake temp problem ... once you overheat them slightly (4.x ?) the temp wont sink anymore, just rise ?It was listed in the failure menu for overheating, but shouldn't the temp sink if you dont use them anymore ?

In my 737NG FCOM I have a table which says that you have to wait about 45min to cool the brakes down. So it seems to take a very long time to cool them when your sitting on the ground. If you have such hot brakes, it´s much more effective to let the gear stay down after takeoff. Then it should take about 7min according to my FCOM.

[Lusche 3]

In my 737NG FCOM I have a table which says that you have to wait about 45min to cool the brakes down. So it seems to take a very long time to cool them when your sitting on the ground. If you have such hot brakes, it´s much more effective to let the gear stay down after takeoff. Then it should take about 7min according to my FCOM.

thx, will try it next time

[hontzt 14]

You also have to realize that it takes up to 15 min for the highest temp to register. I just landed at TNCM and my brakes took almost 30 min to get to 510C, that was on speed Autobrake 3. VR Todd

[JC75 22]

Yes I never seen my brakes heat up past 0.0 either. Not that I'm complaining lol nothing worse than have fire engines follow you to stand in case they explode...pax get jumpy.

[Arkipelago 10]

How are the numbers based? is a brake temp of 3.2 320°C ?