How to really use brakes

[5-in-50]

With regards to GA aircraft, what is considered best practice on the use of brakes?

Points I've obtained from various sources, like CPs, CFIs, POHs etc:
- Don't ride the brakes (obviously). Set a lower power setting to minimise brake usage whilst taxiing.
- Heavy brake application for short periods (like landing roll) is beneficial to the system, as it prevents 'glazing' of the pads
- GA Aircraft pads naturally contact the disc at all times and this is normal
- Park brake should be left off (level surface) during parking to eliminate unnecessary wear/pressure on system during periods of disuse.

Discuss, share your knowledge, ask questions...

[Ixixly]

Agree with point 1, not too sure about Point 2 and 3 though. Point 4 I disagree with a little, I'm really not sure that leaving the Park Brake on would cause that much wear, but I prefer not to leave it on and use chocks instead because of temperature differences, if you're setting it on a scorching hot day in the outback and it gets bloody cold in the evening the fluid condenses and you may no longer have sufficient pressure to keep the aircraft stationary.

[nitpicker330]

All well and good but what does the approved manufactures handbook say?

As they say opinions are like *** ****, everyone's got one....

[skkm]

1. I agree completely – common sense.

2. Agree to some extent – but aerodynamic braking followed by light wheel brake application will probably work out better wear-wise in the longer term

3. If the pads and discs are in constant contact, then presumably this 'glazing' will occur regardless of brake use?

4. Park brake is there for a reason. At my operator, brakes and chocks.

[deadcut]

Most of the Cessna handbrakes are bloody useless anyway. Chocks all the way.

[Ultralights]

4. In a Hangar? definitely NOT! chocks only.

[waren9]

er, seems to be some misconceptions about what glazing is and what causes it. 5 min searching throws up some specialist websites with info on it.

[sheppey]

Most of the Cessna handbrakes are bloody useless anyway. Chocks all the way.
Have you tried writing that up in the maintenance release so an LAME can fix the "useless" park brake?

[Howard Hughes]

How to use brakes:

1. Use them when you need them.

2. Don't use them so often that they are not there when you NEED them.

3. Comply with the manufacturers recommendations! :ok:

[Damien1989]

Don't touch the brakes unless you have to. Do you know how much brake pads cost matey!

[Howard Hughes]

$36k per set on the aircraft I fly! :eek:

[Fred Gassit]

And maybe $36 a set on the one I fly, whats the fuss?

[deadcut]

Have you tried writing that up in the maintenance release so an LAME can fix the "useless" park brake?

Now let's be reasonable here....

[Wally Mk2]

Two answers here both potentially diff.
You own the plane, brakes used very judicially.
Rented/hired or someone else owns it as you see fit to stop the plane doing what you don't want it to.
Brakes are a normal wear & tear item on any moving machine.
You might have babied them over the last few hundred hrs & when it came to that 100 hrly they didn't need replacing but you would never know even if you didn't baby them during the same period, nothing to compare with too many variables here.


Wmk2

[Aussie Bob]

The park brake is to stop the plane rolling in a strong wind or downhill while you are in attendance. Not in attendance? Use chocks.

Leaving a park brake for any length of time pressurises the brake system, is hard on seals and is unreliable. I find it hard to believe any experienced pilot could advocate it.

[dhavillandpilot]

Judicial use of brakes!!!!!!!!!!

I ride my brakes which is SOP for the type. it is cheaper than replacing a pair of GTSIO gear boxes after they chatter and eventually break a gear tooth.

Every aircraft has a different SOP

[triadic]

-Don't ride the brakes (obviously). Set a lower power setting to minimise brake usage whilst taxiing.


- Don't touch the brakes unless you have to. Do you know how much brake pads cost matey!

I once worked for an experienced charter operator who owned & operated some of the larger s/e Cessna's, and his policy was to use the brakes when taxing and keep the engine running smoothly at slightly above normal taxi RPM. His philosophy was that brake pads were cheaper than engine mounts. I believe he was correct.

The other technique that is worth considering, and is perhaps more effective in larger aircraft is that if you are going to use brakes on landing, then it is better (more effective) to use more brake early in the landing roll backing off as you slow down, than to use not much to start with, only perhaps to find you need to apply heavy braking at the end of the roll.

And when you park, always use chocks. No park brake when refuelling either.

[nitpicker330]

"Always use clocks...." Don't ya love auto correct!! :O

[Capn Rex Havoc]

maybe it wasn't autocorrect- maybe he uses clocks as chocks. :E

[Jabawocky]

HH
$36k per set on the aircraft I fly!

Stop showing off about your personal Citation X.

I bet the ones at work on the King Air get a work out. :E

[Howard Hughes]

HH, stop showing off about your personal Citation X.
And then I woke up! ;)

[fujii]

It's not just the brakes to consider, it's also the undercarriage. In my bug smasher where the axle is at 90 degrees to the oleo piston, applying the brakes places a turning moment on the links, dowels and bushes causing wear and subsequent uneven tyre wear. Taxi slowly, use brakes lightly, idle before braking and if you have a enough runway there is no need to brake heavily.

[MakeItHappenCaptain]

Here's a good one for PPL and CPL training...

How about bringing the power to idle before stopping non-gearbox equipped aircraft? Have seen several students from other schools claiming they were told only to bring the aircraft (a C172 in both cases) to idle during the runup check. WTF?

Incompetent instructors teaching their own thing?

Does anyone here keep their foot on the accelerator when they stop their car at a red light?:cool:

[VH-XXX]

I remember there was a couple of Gazelles at Point Cook a few years back. They used to ride the brakes constantly because they didn't want the Rotax 912 gearboxes chattering at idle. I was told the brakes were cheaper than the gearbox to replace at the time.

[Ultralights]

this thread should be renamed, How to overthink a simple subject such as brake use! simple rules about brakes should be, Dont use the parking brake when
1. refuelling
2. in a hangar.
3. dont lock brakes unless you want square tyres.

[displaced gangster]

"Leaving a park brake for any length of time pressurises the brake system, is hard on seals and is unreliable. I find it hard to believe any experienced pilot could advocate it"


Don't agree with this opinion. The parking brake system on the types I have flown is precisely that.
If the manufacture didn't intend to use it as a park brake, it would be listed as a limitation in the AFM/POH.
"Hard on seals and unreliable"? The park brake generally pressurises the braking system if this hard on seals what hope has the normal braking system got?

The only circumstances I could think of not setting the park brake would be in freezing conditions or a brake overheat event.

The PIC is obligated to enter any defect or unserviceability in the appropriate documentation.

[LeadSled]

Folks,
Carbon brakes are starting to make an appearance in some high end GA aircraft ( ain't fashion wonderful) and the technique is a 180 degree shift.
You must use them heavily or not at all, no riding the brakes or "light use".

"Light use" causes rapid brake wear with carbon brakes !!

Tootle pip!!

[dubbleyew eight]

"Light use" causes rapid brake wear with carbon brakes !!

so what? you only use brakes as appropriate. wear is something that has to be sorted out in maintenance.

[Captain Nomad]

The other technique that is worth considering, and is perhaps more effective in larger aircraft is that if you are going to use brakes on landing, then it is better (more effective) to use more brake early in the landing roll backing off as you slow down, than to use not much to start with, only perhaps to find you need to apply heavy braking at the end of the roll.


One should also be careful about using heavy breaking before getting full weight on the wheels however. Heavy feet on the brakes before the aircraft weight has settled onto the wheels is a recipe for locked-up wheels and a flat spot at best, or worse, a blown tyre/s and consequential control difficulties on roll-out leading to more problems.

I once had to help remove a light aircraft stranded on the edge of a wide long runway simply because the relatively new CPL blew a tyre trying to make the taxiway exit. It doesn't impress the boss or customers and it simply isn't worth it!

Use the brakes when you need them but like anything mechanical, be mindful of how they work and their limitations and how the manufacturer wants them used.

For prolonged parking I would never trust a park brake on a sloping surface. A physical chock is cheap insurance for brake ineffectiveness due to temperature and system pressure changes.

Don't brake like a taxi driver, keep it smooth - it is another sign of airmanship or lack thereof!

[LeadSled]

so what? you only use brakes as appropriate. wear is something that has to be sorted out in maintenance.
W8
I guess that's the sort of reply I would expect from too many people on this web site. A figurative "What the hell, it's only the boss's money".
Perhaps if I said that that the AFM Operating Requirement is ---- , would you just ignore the AFM??
Tootle pip!!

[Ultralights]

W8
I guess that's the sort of reply I would expect from too many people on this web site. A figurative "What the hell, it's only the boss's money".
Perhaps if I said that that the AFM Operating Requirement is ---- , would you just ignore the AFM??
Tootle pip!!

As an aircraft owner, i have no problem with using the brakes as required, brake pads are cheap!
as an owner, i always leave brakes OFF in a hangar, last thing i want is someone else going through my aircraft to unlock the park brake to move it. and i hate coming to the airport to find my aircraft parked in behind a temporary visitor, who has locked their aircraft, and left the park brake ON, and parked everyone else in. some owners wil get a tug and pull said aircraft out of the way, park brake on or not. also, helps with access if there is a fire. Brakes off refuelling, for same reason.

as for when the engines running. use as required.. even my aircraft at idle power will have you at 20 kts taxi speed if you dont keep on the brakes.

[A Squared]

Leaving a park brake for any length of time pressurises the brake system, is hard on seals
:confused::confused:

Well, yes, of course it "pressurizes" the system. That's how brakes work. With pressure. If there wasn't any pressure, there wouldn't be any brakes. And engaging the parking brake is no more "hard on the seals" than using the brakes, it doesn't apply any more hydraulic pressure to the seals.

[Capt Fathom]

A Squared, stop encouraging them.

Everyone knows how brakes work..... Don't they? :ugh:

[A Squared]

Everyone knows how brakes work..... Don't they? :ugh:

Dunno. Aussie Bob seems not to, or is that some sort of obtuse comedy act I'm not following?

[Tu.114]

At the flight school I attended, the parking brake was only used when the aircraft was attended. At all other times, it was chocks and most importantly chains attached to a solid concrete foundation on the other end to keep the aircraft in place.

[Aussie Bob]

Dunno. Aussie Bob seems not to, or is that some sort of obtuse comedy act I'm not following?You blokes may have the benifit of operating late model aircraft, my career has gravitated towards ****ters. I stand by what I said.

Stretching a thin wire downwards to pressurise an old braking system is ok short term. Long term, I prefer chocks and an unpressurised brake system.

Well, yes, of course it "pressurizes" the system. That's how brakes work. With pressure. If there wasn't any pressure, there wouldn't be any brakes. And engaging the parking brake is no more "hard on the seals" than using the brakes, it doesn't apply any more hydraulic pressure to the seals.

Sage words indeed from a bloke who lacks understanding of how a hydraulic system wears. No doubt your nervous when geographically displaced from the local Woolworths store. Of course it is impossible for fluid to leak past a worn brake piston.

You can teach a monkey how how to ride a bike until the chain falls off.

[A Squared]

You blokes may have the benifit of operating late model aircraft, my career has gravitated towards ****ters.

and

No doubt your nervous when geographically displaced from the local Woolworths store.

I'm laughing out loud at this stuff. Really? All of this is essentially argument ad hominem: In other words, “I am right because of who I am and who you are”. Most people recognize the fallacy of this sort of "reasoning". If you have to rely on statements of who you are and derogatory claims about the other person to bolster your argument, that's usually a sign that your argument isn't all that strong.

Having said that and recognizing the irrelevancy of that method, I will play along briefly as you seem to find that sort of information compelling.

I own, and maintain myself, an airplane built in 1953.
I've flown and instructed in a number of airplanes built in the 1940's.
I also own and am in the process of rebuilding myself, an airplane based on a 1940's era design.
I have been employed in a GA maintenance shop, wrenching on light aircraft of various vintages.

As far as the geographical displacement, aside from being completely irrelevant to the operation of GA brakes, perhaps on reflection you can recognize the futility of employing such a silly argument on a forum populated by international pilots?

So, now can we dispense with the ridiculous “I am right because I have XXX experience and you are wrong because you do not” arguments.??? Maybe we could discuss the actual operation of brake systems, as that is the topic at hand here. Deal? OK, moving right along …

Sage words indeed from a bloke who lacks understanding of how a hydraulic system wears. ... Of course it is impossible for fluid to leak past a worn brake piston.

Actually, I understand hydraulic systems fairly well. I certainly don't claim to know it all, but you're unlikely to convince me that you know something I don't, merely by claiming I “lack understanding” without explaining what you believe I don't understand. As far as fluid leaking past a worn brake piston, I never claimed anything of the sort, go back and re-read my words. It simply ain't there. If that's your basis for claiming I lack understanding, you miss badly on the point. Yes, seals can leak. And in a high pressure system, a leak past an o-ring can shred the o-ring, I've seen it happen. But that's a high pressure powered system; we're not talking about high pressure hydraulic systems, we're talking about low pressure unboosted systems such as found in light aircraft. A leak past an o-ring in a low pressure system isn't going to damage the o-ring any more than the existing damage or wear which is causing the leak. An o-ring in a brake piston wears because of friction as it moves within the cylinder, not because fluid is seeping past it. Besides, even *if* we were to agree that a fluid leak *causes* o-ring wear (not that I'm conceding the point) why would it cause any *more* wear to set the parking brake than it would to actuate the brakes normally with the pedals to slow or stop the airplane? Seriously, that's not a rhetorical question. I really would like to hear you explain why you apparently think that setting a parking brake is harder on/causes more wear/whatever to the o-rings, than actuating the brakes normally with the pedals. I'd also be interested to hear you explain why you apparently believe that leaving the parking brake set for some length of time causes any *more* pressure to be applied to the brakes than applying the brakes with the pedals. (reference your statement in your first post on this thread) Or if that's not what you meant, maybe you can explain what you did mean.

Perhaps you can do that without trying to claim superior experience, pretending I've said things that I haven't said, calling me a monkey, or the like.


Stretching a thin wire downwards to pressurise an old braking system is ok short term.

If you're referring to a Cessna parking brake system or similar, it's far better to pressurize the brakes by pressing the pedals, then gently but firmly pulling out the parking brake handle to snug up the system and hold the pedals, rather than applying pressure by yanking out on the parking brake handle. For the same pressure applied to the brakes, it places a lot less stress on the rather flimsy structure supporting the parking brake handle and pulleys.

[Aussie Bob]

I'm laughing out loud at this stuff.

That was the intent.

Let's take the case of an aging Cessna. When the park brake is left applied, the hydraulic system is left pressurised. 24 hours later the park brake has minimal effect. The fluid has obviously leaked somewhere. Would I trust it? No. In a percentage of cases the fluid will be a couple of drips on the ground. Before the maintenance release has expires I am out on the tarmac replenishing the fluid via the bleed nipple so the aircraft has brakes again.

Let's take hydraulic systems in general. It is recommended by most in the industry to leave a hydraulic system unpressurised when not in use. Why is this?

There is very little point in further argument, I recommend chocks. Trust your park brake at your peril. The one in my personal aircraft works flawlessly, this does not mean I leave it for weeks on end in a pressurised state, it is my belief that this is not good for the system. No proof sorry. Park your own aircraft how you like.

[A Squared]

For the record, I have not advocated long term use of the parking brake. I agree that it is not secure as it likely to bleed down and release. I'm just disagreeing with your claim that doing so will damage the brake system.

[Aussie Bob]

Perhaps it won't hurt but consider this: If the system is unpressurised for the time you fly, say 100 hours per annum and pressurised heavily by a ham fisted pilot the rest of the year (8660 hours) wouldn't ib be highly likely that the seals would memorise the position they are most often in, which is distorted somewhat by pressure? Dunno, I guess we are splitting straws and enough has been said. Merry Christmas.

[dubbleyew eight]

Leadsled I use the "new posts" button so if a thread doesn't show I miss it.
W8
I guess that's the sort of reply I would expect from too many people on this web site. A figurative "What the hell, it's only the boss's money".
Perhaps if I said that that the AFM Operating Requirement is ---- , would you just ignore the AFM??
Tootle pip!!

if you look closely I wrote "you only use the brakes as appropriate"
wear you sort out in maintenance. no comment at all about bosses money.

so the takehome message here is don't adopt technologies because the "big boys" do it. use appropriate technologies or suffer the maintenance overhead.

I stand by what I actually wrote.