Ok I am back on the rails.. Apologies for my previous post.
Back to the debate
My point about brake temps revolves around some basic metallurgy 101
Almost all aluminium and magnesium alloys used in aviation construction have a melting point at 650 Degree C.(+/- 50 Deg C) and an annealing temp at around 400 Degree C.
Lets assume these alloys structural strength/integrity is not compromised up to 350 Deg C
If you wish to check my figures use the link below
www.matweb.com/search/SearchSubcat.asp?st=sc&catid=352#nfm
A330 wheels are made of these alloys and therefore could not operate in temperatures above 350 Deg C
The A330 has a “eutectic” fuse in each wheel that will melt at 205 Deg C and to use the words out of the manual “ the fuse will melt when the hottest part of the rim reaches 205 Deg C”
The A330 wheel also has an over pressure relief valve in case pressures get to high.
The inner side of the rim/wheel has a stainless steel heat sheild fitted to prevent the working brake temperatures radiating into the wheel and tyre.
The brake temp is measured by an thermocouple probe that is positioned in the core of the brake to give indication of the working temp.
The manual ref given by plastic bug is a special inspection ie Something has gone wrong.
To explain my earlier post about tyres deflating from hard applications of brakes. The brake assy on the A330 is so large that when the "heat pack" (carbon discs and rotors) gets to a certain temp there is insufficient conductivity to wick the heat away before it soaks into the wheel assy thru the heat sheild to the rim to prevent the 205 deg C being felt at the fuse..
From my experience if you have an indicated brake temp at 800 Degs and the eutectic fuse will have melted and I am certainly not going anywhere near a wheel or brake that is that hot and still has the nitrogen in the tyre
