Parking Brake

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voorheesh
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Joined: Tue Jan 04, 2005 5:22 am

Parking Brake

Post by voorheesh »

I think I have read every thread on this forum and understand that the recommendation is to disconnect the parking brake. My IA will not perform this action or sign off an annual if the airplane is in this condition because he believes it is not in conformance with the "type design" of a Cessna 170. He advises me to contact Cessna and see if they will approve the airplane to be configured without a parking brake (I havent yet done so). My understanding of the parking brake operation is that the toe brake must be actuated and the cable must be pulled which allows a device to catch the shaft of the brake through a serration which will then hold pressure on the brake(s)until the device is released by pushing the cable back in. I am told that the parking brake can not be engaged unless the toe brake is actuated. My IA has advised me that my parking brake is adjusted properly, my firewall blanket fits tight, and provided I do not activate the toe brakes in flight, it is almost impossible to inadvertantly set a parking brake in flight. I have been flying for a long time and I probably have some really poor habits that are very hard to break. One habit is that I would never intentionally touch a wheel brake (toe brake) of any airplane while in flight. To do that would be the same as going into beta airborne or forgetting to put the gear down before landing. I have had the words "HEELS ON THE FLOOR" drilled into me so hard that I still think about it every time I fly any airplane. I apply rudder in flight with my toes at the bottom of the pedal. The only time I ever apply pressure to the top is at taxi speed or very slightly in a Xwind. When I slip, I never go "hard over". If I felt I needed to push the pedal to full limit I would go around and set up for another try (unless, of course if the engine quit). If I was taking off and found directional control to be impossible without normaI input, I would abort takeoff. I would appreciate any advice on this. Is my IA wrong? Can the parking brake of a 170 be actuated inadvertantly without pressing the toe brake? If the system is adjusted properly, can the parking brake be actuated without pulling the knob? Has anyone asked Cessna about this? I tried telling my IA that a parking brake is not a certification requirement under CAR-3 and the system can be deactivated with a logbook entry and probably a placard, but he gives me this look which translates to: "we aren't going there". Any ideas would be greatly appreciated. By the way, a new IA is not on the table at this time. I really respect this guy and I would prefer to convince him of the correct way to deactivate this device.
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Bruce Fenstermacher
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Re: Parking Brake

Post by Bruce Fenstermacher »

Oh the games we play with our IAs. I know that's not a helpful comment but thats the thought that comes to mind right now.
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hilltop170
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Re: Parking Brake

Post by hilltop170 »

My IA replaced my original master cylinders with new ones that had no provision for parking brakes. I had never had any trouble in 1100 hours with the parking brakes but after reading the stories on this forum from folks that had problems, removing the parking brakes seemed more like a "safety of flight" issue to me than a correct paperwork issue. I never used the parking brake anyway, I carry chocks.

I didn't see anything in the TCDS that mentioned parking brakes, only the type of wheel and brake assembly required.
Last edited by hilltop170 on Sun Jan 22, 2012 10:51 pm, edited 1 time in total.
Richard Pulley
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1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
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Robert Eilers
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Re: Parking Brake

Post by Robert Eilers »

My I.A. disconnected minefor me.
"You have to learn how to fall before you learn how to fly"
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Indopilot
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Re: Parking Brake

Post by Indopilot »

I was able to get a Field Approval for installing the later cane handle style parking brake from my PMI before he retired. We also carry a set of light aluminum chocks, as insurance. It is nice if you stop on an incline to be able to keep the plane in one place until you can set the chocks. :D
52 170B s/n 20446
56 172 s/n 28162
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mit
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Re: Parking Brake

Post by mit »

Tell your IA that he will be held responsible for any damage cause by a parking break malfuction :twisted:
Tim
russfarris
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Re: Parking Brake

Post by russfarris »

Voorheesh - I can tell you from personal experience that taxiing in a strong crosswind one year at Sun-N-Fun inadvertently engaged my left parking brake, disabling my airplane in a line of not happy outbound pilots. It took a little time to figure out what had happened. I can assure you my parking brake system was properly adjusted and in perfect shape - it's just the nature of the design. Mine has been disconnected for years with the blessing of my IA, who is an active pilot with a practical understanding of what happens in the real world. I'm glad you're happy with your IA, but I'm curious - does he fly himself? Russ Farris
All glory is fleeting...
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GAHorn
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Re: Parking Brake

Post by GAHorn »

Voorheesh, I have pics of our member's 170 that groundlooped at Sun N Fun last year in front of FSDO types who dis-believed his story. (The typical cross-wind, locked brakes story.) I was contacted by the member in an effort to avoid a "709" ride. (recertify his pilot's certificate)

It was a huge deal. The damage was impressive. It was NOT the owners fault... except that he had not followed the advice I strongly urge all owners.... DISABLE THE PARKING BRAKES and REMOVE THE HARDWARE from the tops of the master cylinders.

This is a minor alteration requiring only a logbook entry. It is NOT required equipment. (Placard the Pkg brk control.)

Tell your IA either to do it, or you will find another IA. (If you like I'll forward the pics to you and you can show them. I've already posted some of them here at this forum.)
This is the NICEST pic of the LEAST damage. It does not show the extensive internal damage to the gearbox, or the flat tire, wrecked wheel and brakes.
Image
'53 B-model N146YS SN:25713
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An originality nut (mostly) for the right reasons. ;)
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N3243A
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Re: Parking Brake

Post by N3243A »

Yes, Tell your IA to get a life. For him to hold your feet to the fire on this minor detail shows his lack of common sense when experience shows that the parking brake should be disconnected as shown above by Gahorn.
voorheesh
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Re: Parking Brake

Post by voorheesh »

My IA just wants to know if it is a defect in the brake system or is it induced by the pilot. I consider that a reasonable question. I have had this airplane for 5 years and the only time I have ever used the parking brake is to test it during the annual (per the IA). It works just fine. He says the rudder pedals can be displaced full travel in both directions without hanging up on anything that could affect the parking brake mechanism. So he just wants to know why I am asking him to disable a factory installed system that is functioning properly. Cessna made several thousand of these airplanes and there is no service bulletin, alert, or AD that addresses the parking brake that we can find. I realize this has happened to a few airplanes but the majority have not experienced the problem.
So I will ask the questions again: Can an airworthy parking brake of a Cessna 170 engage in flight without any input from the pilot? If the answer to that question is no, does the pilot have to apply pressure on the brake side of the rudder pedal while airborne to get the parking brake to engage in flight? (Hopefully yes or no answer). If the answer to that question is yes, should the system be safe if a pilot keeps his feet off the brakes in flight? If your answer is just disconnect the system and don't ask questions, there is no need for any further discussion. In that case, I will try and get in touch with Cessna for answers. They still have an engineer available through their customer service department who is somewhat familiar with these old airplanes.
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jrenwick
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Re: Parking Brake

Post by jrenwick »

It's always hard to prove that a problem occurred because of a parking brake that was unintentionally set, because it releases as soon as you touch the brake. For that reason I would be surprised if Cessna or the FAA would be able to confirm there was a problem with the design. (Note that Cessna did change the design in later aircraft.) One great value of an organization like this is the accumulation of anecdotal evidence -- the kind of thing the manufacturer or the FAA couldn't really act upon, but it still serves as a warning for the rest of us.
John Renwick
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Former owner, '55 C-170B, N4401B
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4583C
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Re: Parking Brake

Post by 4583C »

voorheesh
There is an article in the second quarter 2007 issue of THE 170 NEWS page 13 that you might want to read and share with your IA. The third time the author's parking brake locked up he disconnected it! :(
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GAHorn
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Re: Parking Brake

Post by GAHorn »

voorheesh wrote:...So I will ask the questions again: Can an airworthy parking brake of a Cessna 170 engage in flight without any input from the pilot? If the answer to that question is no, does the pilot have to apply pressure on the brake side of the rudder pedal while airborne to get the parking brake to engage in flight? (Hopefully yes or no answer). If the answer to that question is yes, should the system be safe if a pilot keeps his feet off the brakes in flight? If your answer is just disconnect the system and don't ask questions, there is no need for any further discussion. In that case, I will try and get in touch with Cessna for answers. They still have an engineer available through their customer service department who is somewhat familiar with these old airplanes.
The answer to the first question is.... probably not. The second hypothesis you query is.. if the pilot keeps his feet off the brakes in flight will the brakes likely be set?... and the answer is the same..... probably not. (Unfortunately, none of the pilots who accidentally "set" their brakes knew it.... of they'd have not done so, obviously. Pushing on a rudder pedal in flight vigorously will set the brakes if the lever contacts anything, as the lever will be lifted into the locked position. The firewall/blanket is the predominate offender,..but the cable-yoke, tension springs, and apparatus doubtless also play a role. Regardless of 50-year-old Cessna engineering.... airworthy and carefully maintained airplanes are landing with parking-brakes set despite their pilots having been informed about this problem.)
Unfortunately there are numerous pilots who do not activate the brakes intentionally in-flight who have landed with locked parking brakes.

I have personally read the discussion between the CEO at Cessna and lead engineering who have discussed this matter. Their conversations quickly led to the fact that later designs rid themselves of this particular type system, and therefore it is no longer a "current" engineering problem. (Remember the mfr's liabilties are limited by legislation since Mr. Clinton signed it into law.... we can no longer sue them for poor engineering after 18 years, and these airplanes are now five-decades old.) Their conclusion was exactly the same as the questions you have just posed.... if the brakes are not accidentally applied.... the brakes will not be accidentally applied.
It's just too bad that two more 170's have subsequently landed with locked parking brakes since they've had their little discussion in which they concluded to do NOTHING about the early parking brake systems.

Bottom line: No. You don't have to listen. You are free to continue to fly with a poorly-designed parking brake system that occasionally provides the pilot with a locked brake upon touchdown. Absolutely NONE of the victims ever thought it could happen to them, and at least THREE of them have subsequently contacted me and informed me the advice to disconnect them was correct, and they are now (sadly) paying the repair bill. (ONE of them had actually decided to disable his brakes.... but he was waiting for the next annual. Too late.)

Your choice.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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johneeb
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Re: Parking Brake

Post by johneeb »

voorheesh wrote: I have had this airplane for 5 years and the only time I have ever used the parking brake is to test it during the annual (per the IA).
This hole string seems be a awful lot of verbage over keeping a system that is used once per year.
voorheesh wrote:Cessna made several thousand of these airplanes and there is no service bulletin, alert, or AD that addresses the parking brake that we can find. I realize this has happened to a few airplanes but the majority have not experienced the problem.
And currently there is one 170 we are sure of that still has the parking brake hooked up.

"blueldr" isn't here right now, probably off in the Idaho back country for the summer so I will paraphrase him "voorhesh you are gonna die".
John E. Barrett
aka. Johneb

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voorheesh
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Re: Parking Brake

Post by voorheesh »

We are all going to die. There is nothing new there. I guess there are some questions that just rub people the wrong way.
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