Hawker Parking Brake Question

hawkerjet

Well-known member
Joined
Nov 27, 2001
Posts
606
Total Time
8200
For those a little brighter than myself, could someone that knows please explain this system a little better for me. There are several detent positions when setting the Parking brake for a Hawker 900XP/750 and I assume 800/850XP. One knotch after the Emergency position will actually set the parking brake but you can pull it back to the far aft position ( one more knotch )for maximum parking brake effect. To be honest, I only thought there were 3 positions using the parking brake lever; off, emergency and parking. Why would you have that middle detent parking brake position after the emergency position? I have looked in the FSI aircraft manual and read and re read the Parking brake system, but it doesn't quite explain the entire system. Anyone care to explain.
 

Pickle

grumpy puppy
Joined
May 8, 2002
Posts
381
Total Time
no mas
There are only 3 positions for the wheel brake lever. This applies to the 750/800XP/850XP/900XP, that I know. As far as the earlier models (700/800/800A) I am not sure but I can find out for you Monday.

The forward most one is called "normal."

Fully rearward is "park brake."

The middle position is the "EMERGY" position.

You are correct in that there are "clicks" when you go past EMERGY to PARK. Standard prodedure is to pull the lever all the way aft into PARK, not just one click.

Each "click" after EMERGY is a progressive parking position held by a pawl engaging into the notched rack.

What exactly does that mean?? I'll tell you Monday. ;-)
 

hawkerjet

Well-known member
Joined
Nov 27, 2001
Posts
606
Total Time
8200
Thanx Pickle, I'm looking forward to Monday's response......
 

icefr8dawg

Well-known member
Joined
Sep 18, 2003
Posts
413
Total Time
abunch
I used to think the Hawker system was just like any other Jet but it's actually master-slave-high pressure master-slave with a bar of sorts going across the servo rack to depress all of the high pressure masters at once hence the "parking" position. It would be great to see the unit out of the aircraft to see how it really works. Every now and then when you get to a dark aircraft and pull the handle all the way to park you hear what sounds like a mac truck pulling up next to you at a light. That's all the hydraulic servos and valvage moving around underneath you I think.
 

Pickle

grumpy puppy
Joined
May 8, 2002
Posts
381
Total Time
no mas
Since it's a lazy Saturday morning and the kids aren't wrecking the house TOO badly, I went down to my office (that is to say, the unfinished part of the basement with the water heater and furnace) where I keep all my Hawker books.

A little more....

As to the "WHY" you should pull the lever fully aft when you park the plane.

As you may recall, when you pull the wheel brake lever aft into the "PARK" range, pressure from both the emergency brakes and the normal brakes are applied. When you get 1000psi of pressure in the lines you get the white 1/2 or L/R lights on the panel. You don't know which system (emer or normal) is giving that 1000psi, and it doesn't matter. As long as you see the 1/2 or L/R you know you have 1000 psi. However, the "gotcha" is that FULL parking brake pressure isn't applied until you get to the last notch.
 

Pickle

grumpy puppy
Joined
May 8, 2002
Posts
381
Total Time
no mas
hawkerjet, PM me your email and I will email you some stuff you may or may not have.
 

part61

Well-known member
Joined
Sep 30, 2005
Posts
54
Total Time
>3000
I got that "mac truck" sound recently, it was loud i thought somethin was broke.
 

hawkerjet

Well-known member
Joined
Nov 27, 2001
Posts
606
Total Time
8200
OK so the way I now understand the parking brake is like this; When you depress the button and pull the lever past the Emergency Postion, it acts similar to a Hand brake in a car, progressively applying pressure until the last notch is reached ( full aft) when max pressure is applied. Is that about it???
 

FlyingPieceOfSt

Wood You Fly This Plane?
Joined
Dec 20, 2005
Posts
139
Total Time
P-51
I got that "mac truck" sound recently, it was loud i thought somethin was broke.

You will get the "Jake Brake Sound & Rumble" if you apply the brake too quickly.

If you slow the speed of engaging the brake it will never scare you again.
 

Pickle

grumpy puppy
Joined
May 8, 2002
Posts
381
Total Time
no mas
OK so the way I now understand the parking brake is like this; When you depress the button and pull the lever past the Emergency Postion, it acts similar to a Hand brake in a car, progressively applying pressure until the last notch is reached ( full aft) when max pressure is applied. Is that about it???
Sorry I didn't get this to you yesterday.

That is pretty much it, and the reason for it is not as exciting as I had hoped.....

When the vendor made the part that is the wheel brake lever assembly, it had the notches between the "EMERGY" and "PARK" positions. The reason? It just did, they serve no purpose.

Even though each progressive "click" adds more pressure, the correct method is to pull it all the way aft because the full aft position is the one that guarantees full parking brake pressure - even though, say, one click makes the 1/2 L/R lights come on.

So the moral of the story is, there are only 3 positions and please try not to pull it to park when you mean to only go to emergency. ;-)
 

part61

Well-known member
Joined
Sep 30, 2005
Posts
54
Total Time
>3000
Thanks I was gonna ask about that sound next time I went to school.
 

Willy21

Don't ask
Joined
Jul 19, 2005
Posts
522
Total Time
4500
When you depress the button and pull the lever past the Emergency Postion,
Just my personal technique, don't use the button until you are past the Emergency Position. If you get in the habit of doing this, someday when you need to use emergency breaking you will push the button and pull. The brake will go to park and will not stop at the emergency position. As a former sim instructor on the hawker and a current line pilot I have seen many people do this with bad results. Again my personal technique.
 

hawkerjet

Well-known member
Joined
Nov 27, 2001
Posts
606
Total Time
8200
Thanks for your help pickle and thanks for the tip willy.........
 

part61

Well-known member
Joined
Sep 30, 2005
Posts
54
Total Time
>3000
For what its worth

CAE teachs the "reverse grip" when using the emergency brake. That way your thumb wont be in position to push the button.

Anyone else have a friendly/handy Hawker tip??
 

Willy21

Don't ask
Joined
Jul 19, 2005
Posts
522
Total Time
4500
If you walk up to the airplane and it is not leaking fluid be concerned.
 
Top