DAL191 wrote on Sep 11^th, 2011 at 2:51am:


Depressing.

But! The brake temperature does work, I have seen the temperature at around 4 for all of the brakes. It occurred after landing with the autobrakes engaged.

NNewcomb wrote on Sep 11^th, 2011 at 3:16am:

I'll back him up because I've seen the temperatures get to about 4 as well. When using the autobrakes on landing.

I got a 757 DVD and the captain on that one said that the brake temperature scale goes from 0 to 9. 3 or 4 is normal after a fairly heavy brake after landing, it basically never goes to 9, unless the brakes are on fire and are about to fail.

I tried a test flight with maximum payload and about 13500 lbs of fuel to replicate the landing condition of 752 after a flight. I set the autobrakes to MAX, flaps at 20, spoilers armed, no reverse thrust, and landed. Essentially it put a tremendous load on the brakes. The temperaure was 8. I guess at 75-80% payload, 25 flaps, reverse thrust, and autobrakes at 2 the brakes did not work hard enough to register on the scale wims mentioned.

It would be nice if if the autobrakes temperature was mentioned in the manual. With no mention I didn't know whether to look for the real temperature or a scale. I have planes that do one or the other.
Thank you
Michael Cubine

Markoz wrote on Sep 12^th, 2011 at 2:29pm:


Let me know if you succeed in uploading the video. I would like to see it.

Michael Cubine

Mark

The video looks good. Do you know what the red message below TCAS FAIL on the Secondary ECAS at about 1:39 of the video is?

Thank you
Michael Cubine

Quote:

I think he refers to the Autopilot Disconnect, Mark. You are using the Disco Bar there, so that triggers the message.
But you are darn fast, so it wasn't up for long.  


I think the brake temp display implementation is a bit confusing. Without having the tech docs there, I'd say that on braking, the temps (from the energy being converted into heat) go 'into the brakes' and later reach the sensors.
This means that, on landing ,you will mainly see zero impact on that display but on taxi to the gate and after e. g. parking there for 10 minutes, the heat will have built up and also reach the sensors then.

So, at the parking after 10 to 15 minutes, the temp display should give you the highest readings with a slow decrease through brake fans and stuff later.
Maybe they can tune this in 4.5 since your temps got up on the actual brake activation and got down as the auto-brake released the pressure.
I think that this doesn't reflect the rw brake temp monitor's behaviour as the readings are instantaneous right now and also fade away right after braking.


I always brake with the grass strip behind the runway.

It's all about brake wear, buddy.