Russian Airlines and Boeing/Airbus

[hans brinker]

Originally Posted by Winemaker

My understanding is both the number of applications and temperature affect wear; carbon brake wear is much greater at low temperatures and with repeated application.

But unless they start adding brake heaters the only way to get the brakes to optimal temperature is to use the brakes when they are cold, resulting in extra brake wear.....
So what is the optimal way to get brakes to their optimal temperature, both for taxi out, and landing?

[Winemaker]

Originally Posted by hans brinker

But unless they start adding brake heaters the only way to get the brakes to optimal temperature is to use the brakes when they are cold, resulting in extra brake wear.....
So what is the optimal way to get brakes to their optimal temperature, both for taxi out, and landing?

Hard application with temperature build, not repeated soft applications.

[megan]

From the Boeing magazine

.
Because the wear mechanisms are different between carbon and steel brakes, different taxi braking techniques are recommended for carbon brakes in order to maximize brake life.Steel brake wear is directly proportional to the kinetic energy absorbed by the brakes. Maximum steel brake life can be achieved during taxi by using a large number of small, light brake applications, allowing some time for brake cooling between applications. High airplane gross weights and high brake application speeds tend to reduce steel brake life because they require the brakes to absorb a large amount of kinetic energy.

Carbon brake wear is primarily dependent on the total number of brake applications — one firm brake application causes less wear than several light applications. Maximum carbon brake life can be achieved during taxi by using a small number of long, moderately firm brake applications instead of numerous light brake applications. This can be achieved by allowing taxi speed to increase from below target speed to above target speed, then using a single firm brake application to reduce speed below the target and repeating if required, rather than maintaining a constant taxi speed using numerous brake applications. Carbon brake wear is much less sensitive to airplane weight and speed than steel brake wear.

These recommendations are intended as general taxi guidelines only. Safety and passenger comfort should remain the primary considerations.

[ORAC]

Not just Boeing and Airbus aircraft being affected in Russia b6 sanctions….

https://x.com/nexta_tv/status/169930...HhlFHGKbTPQr_A

Flights on Czech L-410 aircraft have been suspended in the Kamchatka Territory due to a lack of spare parts. This is due to Western sanctions on the supply of parts for aircraft.

Kamchatka became the second Russian region that refused to operate Western aircraft. Previously, such aircraft were abandoned in the Komi Republic.

[pilotmike]

Originally Posted by megan

From the Boeing magazine...
Carbon brake wear is primarily dependent on the total number of brake applications — one firm brake application causes less wear than several light applications. Maximum carbon brake life can be achieved during taxi by using a small number of long, moderately firm brake applications instead of numerous light brake applications. This can be achieved by allowing taxi speed to increase from below target speed to above target speed, then using a single firm brake application to reduce speed below the target and repeating if required, rather than maintaining a constant taxi speed using numerous brake applications.

So presumably a single, carefully applied low pressure is optimal to keep taxy speed about right is ideal - even better than the reduced but nevertheless repeated "single firm brake application[s]" which are suggested.

[Locked door]

Not if you don’t want to set fire to your brakes. A single continuous application will overheat the brakes very quickly.

Cadence braking (allowing the speed to build up before slowing to walking pace) creates cooling periods which slows heat build up.

[Winemaker]

Originally Posted by pilotmike

So presumably a single, carefully applied low pressure is optimal to keep taxy speed about right is ideal - even better than the reduced but nevertheless repeated "single firm brake application" which are suggested.

Think of it like going down a steep mountain road. You can keep a constant brake pressure on or allow the speed to build then slow down with a harder application. If you chose the first method, constant brake pressure, you are soon going to smell that nice odor of cooking brakes.