What is the acceptable position of the brake wear indication (PIN) for an A320 to be safely dispatchable?

  • $\begingroup$ Just curious, why wouldn't you ask one of the folks that actually work on your plane? $\endgroup$ – Michael Hall Oct 10 '20 at 14:26
  • $\begingroup$ Its always better to know different points of view, that's why StackExchange is there!! $\endgroup$ – Islam Elsayed Oct 10 '20 at 14:33
  • $\begingroup$ But surely your maintenance department has a policy, that they would be required to follow. What value then is there in asking for a "different point of view"? $\endgroup$ – Michael Hall Oct 10 '20 at 22:04
  • $\begingroup$ Asking such policies (procedures) to apply them in real-time flights is different than getting to know different points of view just for sharing purposes. $\endgroup$ – Islam Elsayed Oct 11 '20 at 13:39
  • $\begingroup$ Fair enough then, but these "points of view" aren't generally opinions. For example, the 1mm limit in the answer you accepted, does this match your maintenance procedure? If it comes from the Airbus AMM it ought to match every operator's procedure, correct? So then do you expect something different? I am all for sharing our differences of opinion to keep things interesting, but some things are pretty black and white... $\endgroup$ – Michael Hall Oct 11 '20 at 15:17

To answer your question the limit is 1mm. It cant be less than this value. At lengths greater than this value brake wear can be measured without any specific brake temperature value. However at values less than 1mm Airbus has a specific brake temperature of 60 degrees Celsius to measure the brake wear.

At high brake temperatures the heat from the carbon brakes causes the pressure plate to expand to which the wear pins are connected to. This can easily cause a false indication of the brakes actual lining wear and if the parking brake is not applied can cause a large false indication. Therefore the recommendation of the cold temperatures. Applying the parking brake is of importance as the actual wear of the brakes lining can be gauged.

As mentioned soo long as it's over 1mm with the parking brake ON it's possible to measure brake wear at any brake temperature.

The official reference as per the AMM is also attached. enter image description here

  • $\begingroup$ @IslamElsayed for certain reasons I can't share that information on open comments. $\endgroup$ – Jai Oct 10 '20 at 15:11
  • $\begingroup$ I can explain the reasons to you via other mediums. Can I contact you on some other platform ? $\endgroup$ – Jai Oct 10 '20 at 15:18
  • $\begingroup$ Unfortunately I'm not on twitter any other platform? $\endgroup$ – Jai Oct 10 '20 at 17:59

There are two wear pins. If the end of either pin touches the machined part of the piston housing the heat pack is worn out and the brake must be replaced. Measurement must be done when the brakes are cold. If one wear pin is missing, check to make sure the other pin is there and looks ok. If both pins are missing the brakes need to be replaced.


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