Why not use parking breaks long term?

[Avi]

I know using parking breaks long term is not good due to the different temps and pressures. I know because of that it may release the parking breaks. Does anyone have anything else or better to add to that?

[Aviatard]

Yes. It's "brakes."

[SuperchargedRS]

If you leaving a plane somewhere for a while you would have it tied down right? Maybe have some chalks? WHY WOULD YOU HAVE YOUR PARKING BRAKE ON TO?

I think of it like this; when you pull that brake you are pulling a cable and putting stress (tension) on everything attached to it, why bother with doing that if you dont have to.

The parking brake is not that useful, if you think you need it, you should probably tie down the plane down and if you do that you really dont need it..

This is why I just carry my nice 3 strand line with me an don't use the parking brake.

[Avi]

haha thx Aviatard

[_dwj_]

Also, someone might need to move your plane, e.g. to cut the grass, repair tarmac, etc.

[Avi]

I was hoping someone knew why exactly the brakes did that

[ywgflyboy]

They can also freeze in cold temps... Friction creates heat, then moisture adhering can freeze after the aircraft is parked.

[MichaelP]

Reliance on feeble light aeroplane brakes is stupid!

If you leave the brakes on long term, be prepared to find a pool of fluid on the floor and brakes that will no longer work.
I have found this many times and I used to levy a fine of £5 on anyone leaving the brakes on in my aircraft.

Take your Cherokee for example, the brake handle is connected to a single master cylinder that is connected to the pedal mounted cylinders through which it imparts it's single pressure.
This single master cylinder will fail over a period and it will fail if left on for a long period unless you are very very lucky.
I've seen a Cherokee's carpet flooded with hydraulic fluid with the parking brake on but no pressure left in the system for the brakes to be on.

Automobile designers are not so stupid.
The hand brake is usually connected via a cable to the rear brakes. They know how even the far superior braking systems fitted to cars can fail.

When you realise how poor light aircraft brakes are, you will have a better appreciation for not having anything in front of you when you do your runup!

[Big Pistons Forever]

My 0.2 cents

Parking brakes use in large aircraft is very different from light aircraft. Use of the parking brake is a universal SOP in large aircraft. However they have a proper system that actually works. The parking brake on light aircraft is at best an after thought add on to the mainwheel brake system. It is important to know how the parking brake system on your aircraft works, in order to understand its weak points. For example Pipers and Cessnas have completely different sytems with different points of vulnerabilty. The Piper system is IMO far superior because it at least directly traps all the brake pressure with a catch at the centre master cylinder. The cessna system uses a set of cable to depress the pedals and almost never applies equal force to both wheels and is prone to suddenly releasing, and/or not fully releasing when selected off.

FYI I tell my students to only use the parking brake in circumstances where the aircraft must be prevented from rolling for a short time. The most common circumstance is when it is parked on a incline such that it may roll when you get out. In this case set the parking brake while you get out and place the chocks and then release it. Apply it again just before you remove the chocks prior to getting in and starting up. Basically you never want to leave the aircraft unattended with only the parking brake holding it and under no circumstances should you trust the parking brake to hold the aircraft with the engine running.

[just curious]

Why not?
Well, on Kingairs- Put them on when you've taxied through a little bit of snow- they freeze
When they're hot, they seize. When it's just right... the bressure bleeds off and they aren't working.

Go with chocks.

[HS-748 2A]

Those are all good answers.

One more reason; I watched a hangar burn down one time. (a BIG hangar, full of G.A. airplanes.)

There were only a few people there to help in time and they unchocked evrything they could and started pulling and pushing. A couple airplanes that were quite close to the door never got out.

Their doors were locked and their park brakes set. (on a dead-level floor.. )

By the end, enough airplanes in that configuration impeded any hope for some of the airplanes that would have been easily rollable near the back of the hangar.

In all, about 12 airplanes were lost, including a PT-17.

Just one more thought about park brakes, particullarilly in wooden hangars.

[767]

If wheel chalks are available, leave the parking brake off, regardless if your parking for 1 second or for 1 decade. !

[Cat Driver]

delete

[Hedley]

I hate parking brakes. The best they can do is cause trouble.

[5x5]

I hate parking brakes. The best they can do is cause trouble.

+100 - I dearly wish there was an STC so we could take them out. They are a horrible maintenance expense and, as all the others have stated, are essentially useless.

[MichaelP]

Their doors were locked and their park brakes set.

Fundamentals again.

A couple of the earliest things I learned when doing my PPL was never leave brakes on in the hangar, and never leave control locks in in the hangar.
There's a lot less damage done to controls if they are allowed to move when struck by something (usually my forehead!).

If you read the RAF Pilot's Notes for the Dakota they very specifically write not to leave the brakes on!

[Bede]

Quick comment on park brakes in large aircraft. They are connected to the hydraulic system. At night, everything is shut down and the park brakes are no longer "brakes". This has caught a few rampies by surprise. "Forget the chokes, the brakes are on." The next morning some rampie comes up to you and bad mouths the previous day's crew for not putting the park brake on.

[Brice]

Chalk:


Chock:

[MichaelP]

Choc!

[Brantford Beech Boy]

All good stuff.

Agreed, the park brake is there for very short term use.
I find them most useful when you've brought the plane to a stop and will sit for a few minutes, like when you're #10 in sequence for takeoff and are stop and go to get the runway.

also

helpful when doing a run-up although I still keep my feet on the pedals lest they don't impede forward movement at the higher power settings.

and

the park brake should become part of your "flow" in any emergency on the ground.
Bring the airplane to a stop and set the park brake. Deal with emergency. Particularly with a fire.
Last thing you would want is the airplane rolling away whilst attempting to extinguish a fire or (even worse) towards you while running away from the burning plane.


but like others have said, if the airplane is to be left alone for ANY amount of time, park brake OFF and chocks in.

BBB

[Aviatard]

Yoke:



Yolk:

[Dagwood]

Brake:


Break:

[Dagwood]

So, what have we learned from all this

1. Dew knot leave breaks on inn the hanger inn case it needs too bee toad.

2. Parking breaks are knot two bee left unattended.

3. Breaks may seas if ewe fore get them on.

4. All weighs Thai down yore air plain.

5. Pie lots are to leave the yolk unlocked and the we'll chalked.

6. and finally, pie lots cant speel.

[Big Pistons Forever]

So, what have we learned from all this

1. Dew knot leave breaks on inn the hanger inn case it needs too bee toad.

2. Parking breaks are knot two bee left unattended.

3. Breaks may seas if ewe fore get them on.

4. All weighs Thai down yore air plain.

5. Pie lots are to leave the yolk unlocked and the we'll chalked.

6. and finally, pie lots cant speel.

thats whey two fun making

[Bede]

Brantford Beech Boy,

Are you Aussie?? Only Aussie's use the word 'whilst'