PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Tech Log (https://www.pprune.org/tech-log-15/)
-   -   The high cost of heavy braking (https://www.pprune.org/tech-log/665115-high-cost-heavy-braking.html)

ScepticalOptomist 24th March 2025 23:08

Not sure exactly, but I have noticed some brakes are definitely worse than others - perhaps uneven wear on the left vs right causing different amounts of heat build up.

The 737-800 has the worst brakes out of any Boeing I've flown - can be quite difficult to apply evenly and without dancing down the runway, especially with moderate application.

I tend to leave the auto brakes in as long as possible for this reason - much smoother application. My pet peeve is the heavy braking to make a rapid exit instead of taking an extra minute to taxi back to the bay.

Junkflyer 25th March 2025 06:56

On the 717 we use, there are no autobrakes. Typically wait until 100 knots or below before applying brakes if it is safe enough.
Often 30mminutes turns so brake heating may be an issue. The brake fans from MX work well if needed.

pineteam 25th March 2025 07:38

On the Airbus, a few things I have learnt from their official documentations:
* Do not ride the brakes. In a straight line let the aircraft accelerate up to 30 kts then one smooth application down to 10kt.
* Minimise the brakes applications as much as possible.
* Know the critical brakes wear temperature. It varies from manufacturer. On The Messier the worst temperature is around 180 degrees celcius.
* After landing consider the last high-speed taxiway to vacate (if no restrictions) to minimise the use of brakes.
* Consider single engine taxi also to minimise the braking.
* Wait at least 5 min after landing to set the brakes fans or entering the gate whichever comes first unless you expect the brakes to exceed 500 degrees.

itsnotthatbloodyhard 25th March 2025 21:54


Same with parking - smoothly onto the stand then full on the brakes at the very end when you have a readout of your groundspeed and also the exact distance to run. Aaarggh!
Probably being done as a helpful technique to educate those passengers who like to jump up while the aircraft’s still moving…
(and no, I’m not seriously advocating this and have never personally done it)

Denti 26th March 2025 07:44


Originally Posted by itsnotthatbloodyhard (Post 11854221)
Probably being done as a helpful technique to educate those passengers who like to jump up while the aircraft’s still moving…
(and no, I’m not seriously advocating this and have never personally done it)

I know some do that. I try not to as the cabin crew in our operation is already up and not in their seats because they are already disarming the doors.

Sometimes it happens anyway, had it the other day when pulling into a parking stand in ZRH when the parking system jumped from 0.8m to STOP.

punkalouver 26th March 2025 09:37


Originally Posted by itsnotthatbloodyhard;11854221
[color=#000000
Same with parking - smoothly onto the stand then full on the brakes at the very end when you have a readout of your groundspeed and also the exact distance to run.[/color]

It is quite possible to bring the aircraft, at least big Boeing aircraft, to a stop at the gate without any feeling to the pax that the aircraft stopped. It is just a matter of watching the GS and outside reference and smoothly increasing brake pressure appropriately as the stopping point is approached.

Harry Grout 26th March 2025 14:41

I can honestly say that I have never once looked at the GS on big aircraft when parking them! No complaints in 35 years.

Chesty Morgan 26th March 2025 16:55


Originally Posted by punkalouver (Post 11854447)
It is quite possible to bring the aircraft, at least big Boeing aircraft, to a stop at the gate without any feeling to the pax that the aircraft stopped. It is just a matter of watching the GS and outside reference and smoothly increasing brake pressure appropriately as the stopping point is approached.

You'd want to be reducing brake pressure as you approach the stop point or you just increase the rate of deceleration.

But I'm sure you know that.

ScepticalOptomist 26th March 2025 20:49


Originally Posted by punkalouver (Post 11854447)
It is quite possible to bring the aircraft, at least big Boeing aircraft, to a stop at the gate without any feeling to the pax that the aircraft stopped. It is just a matter of watching the GS and outside reference and smoothly increasing brake pressure appropriately as the stopping point is approached.

Bigger aircraft were always much easier to be smooth - the smaller jets (737) were always harder. That's true for the entire operation - larger jets I found easier to fly / handle / park.

semmern 2nd April 2025 08:07


Originally Posted by Check Airman (Post 11853551)
MED is seldom used in the real world, because the declaration is excessive. On all but the newest A320’s, low is too little deceleration. In the sim, low tends to have you sliding about a bunch, so that’s probably why he used medium.

MED is used all the time in winter up here. Low is all but useless once it gets a little slippery.

Locked door 2nd April 2025 20:39

if low is useless in slippery conditions then selecting MED will have very little effect on the landing distance.

LOW and MED give a preset rate of deceleration. If low is unable to achieve the target rate of deceleration due to a slippery runway selecting MED or even max manual braking won’t increase the rate of deceleration. Increased braking effort will only make a difference if you pass over patches of grip and if that’s only on one side you run the risk of a rapid yaw and then potentially going off the side.

Spoilers and reverse thrust are your friends on slippery runways as they’re symmetrical.

LD

compressor stall 3rd April 2025 03:30

Locked door
It’s not the lack of friction that’s limiting. It’s the time it takes to kick in.

There was a SB a few years ago so in LO now takes 2 second to kick in not 4 as manufactured, which many found a little tardy. Not all aircraft have it.


All times are GMT. The time now is 04:30.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.