Parking Brake Locked Up in Flight??

[Shadrach]

@Skates97 how much fuel on board when you departed and how much on landing?

[takair]

7 hours ago, Skates97 said:

I was actually thinking about Occam's razor yesterday, and that would point to exactly what you are saying. I am not above stupid mistakes, and I'm sure I will make others in the future. It's a constant learning process and as I have said at other times you just hope that you learn from the mistakes you make and that thy are small enough that there are no serious consequences from any of them. If that is what happened it is a bit disconcerting that I have no recollection of it... I would sure feel a lot better if I could run it back in my mind and say "yep, I think I remember doing that."

Of course if it was from a touch and go years ago I could blame it on a previous owner as I have only had the plane for two years. 

New tubes and tires should be on it, my wife picked them up at AS this morning and dropped them off at the shop and they already had the wheels off and were waiting on the new ones. Wanted to put the Michelin Airstops in but the only tubes that AS carried that had the bend in the valve stem were some expensive Goodyear tubes. Did not hear back from the shop today but it wouldn't be the first time they finished something on my plane and put it back in my hangar without a call to let me know it was done. They aren't there Friday so I will just head out there Saturday morning to see if it is done. Still want to know why I couldn't get the cable to release no matter how hard I pushed on it. It is probably the original cable and may just have bound up, again hoping to hear something from the mechanic about it.

That's funny stuff. Always get a chuckle out of some of the creativity here on MS.

Doesn't prevent the goofy stories, just changes the opening line of the article from "He did not file a flight plan" to "Despite filing a flight plan..."

Richard...Thanks for keeping us posted.  I guess they got it to release somehow, just haven’t explained it?  Slight topic shift, you mentioned you found tubes with bent valve stems?  Would you mind sharing the part number?  Are these with a 90deg. bend? I can never seem to find them when I need it.

[Marauder]

7 hours ago, Skates97 said:

I was actually thinking about Occam's razor yesterday, and that would point to exactly what you are saying. I am not above stupid mistakes, and I'm sure I will make others in the future. It's a constant learning process and as I have said at other times you just hope that you learn from the mistakes you make and that thy are small enough that there are no serious consequences from any of them. If that is what happened it is a bit disconcerting that I have no recollection of it... I would sure feel a lot better if I could run it back in my mind and say "yep, I think I remember doing that."

Of course if it was from a touch and go years ago I could blame it on a previous owner as I have only had the plane for two years. 

New tubes and tires should be on it, my wife picked them up at AS this morning and dropped them off at the shop and they already had the wheels off and were waiting on the new ones. Wanted to put the Michelin Airstops in but the only tubes that AS carried that had the bend in the valve stem were some expensive Goodyear tubes. Did not hear back from the shop today but it wouldn't be the first time they finished something on my plane and put it back in my hangar without a call to let me know it was done. They aren't there Friday so I will just head out there Saturday morning to see if it is done. Still want to know why I couldn't get the cable to release no matter how hard I pushed on it. It is probably the original cable and may just have bound up, again hoping to hear something from the mechanic about it.

That's funny stuff. Always get a chuckle out of some of the creativity here on MS.

Doesn't prevent the goofy stories, just changes the opening line of the article from "He did not file a flight plan" to "Despite filing a flight plan..."

It will be interesting to learn of the details when you get this figured out. If I am reading things correctly, there is a speculation that during the flight you pulled the parking brake inadvertently and when you landed used the brakes which would now lock and cause the skidding. Is that the current theory? I know piecing things together can be challenging.

Not as obvious as this Corsair owner at our 2013 airshow. He landed with his feet on the brakes and put the plane on the nose. Heck of a lot more expensive learning for him.

[bob865]

14 hours ago, Yetti said:

More than likely you were trying to fly lean of peak and the reduced manifold pressure suck the excess brake fluid through the reverbulating framulator.   Once the suction was applied to the brake fluid, the extra velocity from flying LOP via adverse momentum cause the PB Knob to retract to the rear of the plane.  After you exited the black hole. Really there was no way to prevent this from happening.

Your explanation reminds me of the rockwell retro encabulator.  I've been working on replacing internal combustion on my plane with the modial interaction of magneto reluctance and capactive redactance.  Seem much like a much more efficent method of flying since we aleady have magnetos and there are capactiros in the the good ole SOS box and magnetos.

Link for reference: https://www.youtube.com/watch?v=RXJKdh1KZ0w

On a more serious note, did I miss the note that the brakes finally released?  I was thinking the last post I saw said you went by with it on jacks and the wheels were still locked up.  What did the mechanic do to get them to release?  Did he manipulate brake valve to get it to happen?

[Shadrach]

My theory is shaky at best but it's something like this.

Parking brake set for run up at KFOM. Parking brake turned off for departure.  Cable malfunctions and brake is not actually released.  Fire breathing O360 is able to over come brake drag for departure after refueling. Take off roll longer than usual, but not alarming due to the DA at the 5000ft field and fuel load for 400NM trip.  Arrive at KAJO 200lbs lighter. The landing is smooth with a gentle weight transfer to the wheels. Lightly loaded tires start skid easily. Tires and tubes compromised long before the plane comes to a stop. 

[carusoam]

Theories are good...

1) pretty easy to overcome brakes with full power, or even run-up power... hence the reason some people don’t use the parking brake for run-up....

2) Brakes applied early in the landing phase will scrub the rubber off the tire pretty quickly...

 

Two oddities continue on...

1) mounting of the valve itself... (missing bolts?)  Expect If the bolts are missing.  The valve isn’t held firmly in place.  The valve may move instead of moving the lever... this would leave the valve not operating as expected...

2) brakes remained locked when everything was over...

 

Thanks to Richard for sharing the experience...  

Thanks to MSers... who always contribute, something...

Best regards,

-a-

[0TreeLemur]

4 hours ago, bob865 said:

Your explanation reminds me of the rockwell retro encabulator.  I've been working on replacing internal combustion on my plane with the modial interaction of magneto reluctance and capactive redactance.  Seem much like a much more efficent method of flying since we aleady have magnetos and there are capactiros in the the good ole SOS box and magnetos.

Link for reference: https://www.youtube.com/watch?v=RXJKdh1KZ0w

On a more serious note, did I miss the note that the brakes finally released?  I was thinking the last post I saw said you went by with it on jacks and the wheels were still locked up.  What did the mechanic do to get them to release?  Did he manipulate brake valve to get it to happen?

Ahem....   I believe you are mistaken sir.  What you are referring to is the TURBO encabulator.

[Skates97]

2 hours ago, Shadrach said:

My theory is shaky at best but it's something like this.

Parking brake set for run up at KFOM. Parking brake turned off for departure.  Cable malfunctions and brake is not actually released.  Fire breathing O360 is able to over come brake drag for departure after refueling. Take off roll longer than usual, but not alarming due to the DA at the 5000ft field and fuel load for 400NM trip.  Arrive at KAJO 200lbs lighter. The landing is smooth with a gentle weight transfer to the wheels. Lightly loaded tires start skid easily. Tires and tubes compromised long before the plane comes to a stop. 

Plausible. Take off roll was not longer than expected, however although it was a 5000' Elevation it was also cold and runway 22 is 1.4% gradient downhill which combined could lend to not much more takeoff roll than expected under normal operations. I like that theory a lot better than me having no idea if/when I pulled the brake in flight...

16 hours ago, Shadrach said:

@Skates97 how much fuel on board when you departed and how much on landing?

Fuel load was 46 gallons at take off and with the two of us plus what we were hauling with us I had the takeoff weight at 2,284. I have exact numbers in my tablet at home for fuel burn but it was right at 3 hours so figure 16-18 gallons when landing.

2 hours ago, carusoam said:

Theories are good...

1) pretty easy to overcome brakes with full power, or even run-up power... hence the reason some people don’t use the parking brake for run-up....

2) Brakes applied early in the landing phase will scrub the rubber off the tire pretty quickly...

 

Two oddities continue on...

1) mounting of the valve itself... (missing bolts?)  Expect If the bolts are missing.  The valve isn’t held firmly in place.  The valve may move instead of moving the lever... this would leave the valve not operating as expected...

2) brakes remained locked when everything was over...

 

Thanks to Richard for sharing the experience...  

Thanks to MSers... who always contribute, something...

Best regards,

-a-

Another member who has the same valve and reservoir was nice enough to send me multiple pictures of the way his valve is mounted as well as the routing of his cable and where the cable is secured. The valve mounting only to the bottom of the cylinder is identical, I suppose there isn't much flex with just the fitting between the reservoir and valve. I do not know about the way my cable is routed or secured.

I will have more to report tomorrow after I have been out to the hangar. I won't know what the shop has to say until Monday when they are back. They do good work, but their follow up is terrible. I can't remember if it was when they did my generator or governor, but I hadn't heard from them in a few days and when I got in touch with them he said "Oh yeah, it was done on such and such day (I can't remember the day) and is back in your hangar. The invoice is there, get me a check when you can."

9 hours ago, Marauder said:

It will be interesting to learn of the details when you get this figured out. If I am reading things correctly, there is a speculation that during the flight you pulled the parking brake inadvertently and when you landed used the brakes which would now lock and cause the skidding. Is that the current theory? I know piecing things together can be challenging.

Not as obvious as this Corsair owner at our 2013 airshow. He landed with his feet on the brakes and put the plane on the nose. Heck of a lot more expensive learning for him.

 

He had a much worse day than I did...

10 hours ago, takair said:

Richard...Thanks for keeping us posted.  I guess they got it to release somehow, just haven’t explained it?  Slight topic shift, you mentioned you found tubes with bent valve stems?  Would you mind sharing the part number?  Are these with a 90deg. bend? I can never seem to find them when I need it.

I think they are these ones, 06-05305, G15/6.00-6 Flight Mate™, Also for 600 x 6 tires. https://www.aircraftspruce.com/catalog/lgpages/600-6.php

My wife left the invoice at the hangar, "In it's rightful place of honor" (what she calls the stack of all the other receipts from the past two years of ownership).  I will double check it tomorrow to confirm. 

[gsxrpilot]

Damn! Don't they realize they've left the whole MooneySpace world in suspense for the whole weekend!!

[MIm20c]

My theory is the parking brake cable is frozen up. When you released the parking brake before takeoff you pushed hard enough to just barely open the valve to release the pressure. The frozen (rusted) cable rebounded after you released the knob. It then held the valve closed so when you depressed the brakes hard enough (sometime during the flight) it set the brake again. 

Disconnect the cable and force some triflow in it as you move it in and out. You also might want the mechanics to change out the pin that holds the arm to the plunger. It should be a stainless steel rivet not a cotter key. 

[Shadrach]

32 minutes ago, MIm20c said:

My theory is the parking brake cable is frozen up. When you released the parking brake before takeoff you pushed hard enough to just barely open the valve to release the pressure. The frozen (rusted) cable rebounded after you released the knob. It then held the valve closed so when you depressed the brakes hard enough (sometime during the flight) it set the brake again. 

Disconnect the cable and force some triflow in it as you move it in and out. You also might want the mechanics to change out the pin that holds the arm to the plunger. It should be a stainless steel rivet not a cotter key. 

I don’t think ambient pressure, much less the pressure at altitude would be enough for fluid to enter the system with the valve closed. Easy to test on the ground.

[Ragsf15e]

I’ve taxiied with my PB locked before and it definitely didn’t take full power (like jumping chocks might).  Wheels turned (heavy and slow).  Took a while to notice.  Took longer than runup area to takeoff position.  I could see you forgetting it,  taking off with it engaged and locking the wheels on landing at high speed/light weight.  Blow both tires real quick.  Don’t know why it wouldn’t disengage after though.

BTW, I stopped using mine like most of these other folks.  However, as someone who’s had their 65,000# aircraft roll away after shutting down, I would use it if I was on a hill or high wind without chocks!

[Shiny moose]

My theory would be the most simple one.  

Run up was done with parking brake on, pressure was not release properly due to muscle or cable malfunction (probably not the valve), then the  brake system was over powered for takeoff. 

A Funny brake story

I did watch a  couple of guys who were not insured to fly due to time in type, do V1 cuts on the runway in a brand new Beechjet one day until they needed fuel( maybe 5-6 runs) when they parked it the brakes were smoking big time,  blew the plugs on both mains. Then the  chief pilot tried to jack the plane on the ramp  with a  2 ton floor jack and a block of wood under the wing  to take the wheel off! I stopped him !!  He was going to fix it himself so the boss wouldn’t find out(hahhaaa) This was after he flew a brand new Barron into a flock of geese resulting in big time wing damage but windscreen intact . He then flew a C425 coming back from brand new paint into the tree tops during IFR approach, missed, then landed 30 miles away with nose damage, gear paint scraped up, props banged up, intakes damaged and full of twigs and tree stuff! PT6 is an amazing engine!!! His excuse was a flying tree at altitude due to tornadic activity in the area.  I dont know if he buys lottery tickets! 

[Bob_Belville]

I am very surprised to hear that "most pilots" do not ever use the parking brake. I always set the brake to start the engine and to do the pre take off run up per my check list. The brakes hold firmly at least to up 2000 RPM though I keep my feet on the rudder pedals just in case. 

(And I've parked on ramps, including at self serve pumps, that were so sloped that the plane would be moving before I could get out and chock the wheels.)

If the parking brakes did not hold I would fix them.

   

[Shadrach]

2 minutes ago, Bob_Belville said:

I am very surprised to hear that "most pilots" do not ever use the parking brake. I always set the brake to start the engine and to do the pre take off run up per my check list. The brakes hold firmly at least to up 2000 RPM though I keep my feet on the rudder pedals just in case. 

(And I've parked on ramps, including at self serve pumps, that were so sloped that the plane would be moving before I could get out and chock the wheels.)

If the parking brakes did not hold I would fix them.

   

My brakes hold well. I know because I’ve had to jump start the plane alone. I don’t use the park brake on start up because I’m using the brake pedals. 

[Bob_Belville]

1 minute ago, Shadrach said:

My brakes hold well. I know because I’ve had to jump start the plane alone. I don’t use the park brake on start up because I’m using the brake pedals. 

I suppose one good reason to use the parking brakes for engine start and mag check is as a backup to holding toe pressure on the pedals. I can pat my head and rub my tummy at the same time but stuff happens and a momentary lapse of attention could be embarrassing. 

[Ragsf15e]

Momentary lapse like forgetting to release the parking brake for takeoff?

[Ragsf15e]

1 hour ago, Bob_Belville said:

I am very surprised to hear that "most pilots" do not ever use the parking brake. I always set the brake to start the engine and to do the pre take off run up per my check list. The brakes hold firmly at least to up 2000 RPM though I keep my feet on the rudder pedals just in case. 

(And I've parked on ramps, including at self serve pumps, that were so sloped that the plane would be moving before I could get out and chock the wheels.)

If the parking brakes did not hold I would fix them.

   

Generally I agree with following the checklist as written, and it does say to set PB before start, but not before runup/pre takeoff checks.  In the taxi section it clearly says to disengage PB, but the pre takeoff section does not say to reengage.  At least 1968 F.

 

[Bob_Belville]

17 minutes ago, Ragsf15e said:

Generally I agree with following the checklist as written, and it does say to set PB before start, but not before runup/pre takeoff checks.  In the taxi section it clearly says to disengage PB, but the pre takeoff section does not say to reengage.  At least 1968 F.

 

You'll note that I referenced "my" checklist.  (I don't think the original '66E Owner's Manual lists setting the parking brakes at all.) 

I admit that there are times when check lists can be finessed, with caution. Departing Sun n Fun a few years ago I recall that the plane never stopped from the time we started from the grass in vintage parking until be were airborne. Controls check, trim, flaps, mags, etc. were all done while taxiing and we were cleared for takeoff as we reached the runway.     

[Ragsf15e]

Well, I guess if it’s not in the checklist, that’s why “most” Pilots don’t use them.  I agree you can add it to your own if you like, but that’s your own technique.  Don’t be surprised if other people use different techniques.

In other parking brake designs, it might be more important to check, more useful, and harder to leave engaged.  However, our parking brake is merely holding most/some/all the pressure from your toes and letting you remove your feet from the pedals.  If you don’t have anywhere to go (like outside the airplane- jumping it maybe?) then there’s no big reason to use it at all.

If you do want to use it, that’s fine as well.  Just put a second checklist item at the end of pretakeoff... parking brake, disengage!

[Shiny moose]

I use my parking brake for run up also. It holds well but I’m sure I could overpower with my fire breather!!

[salty]

Ok am I not understanding how the parking brake works? 

If you push the brakes as hard as you can and set the parking brake, how could you possibly overpower it any more than you could just by using the brakes normally? What am I missing?

[Marauder]

Ok am I not understanding how the parking brake works? 
If you push the brakes as hard as you can and set the parking brake, how could you possibly overpower it any more than you could just by using the brakes normally? What am I missing?

Having rebuilt my parking brake this afternoon, it’s not the most robust set up. A quarter inch sized piston with 2 small O rings on it. If either of the O rings are slightly compromised, I could see fluid leaking by and not provide full holding power. I think that is what was going on with mine. The new and old O rings were remarkably different in condition. Mine just never held.




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[gsxrpilot]

I've used my parking brake exactly once. I parked on a ramp and there weren't any chocks or tie downs available. I was nervous the entire 30 minutes I was away from the plane. I now carry a set of chocks in the plane and therefore will not likely need the parking brake ever again. 

[Marauder]

I've used my parking brake exactly once. I parked on a ramp and there weren't any chocks or tie downs available. I was nervous the entire 30 minutes I was away from the plane. I now carry a set of chocks in the plane and therefore will not likely need the parking brake ever again. 

The only time I really needed mine was parking at a nearby airport for some avionics work. The ramp was sloped and I knew I needed the parking brake which didn’t work.

There was one reward. I now hold the world’s speed record for exiting a Mooney.


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