"A" Model Ground Control After Brake Failure

Copied below is an excerpt from a message from Mike Thompson about the race today (9-10-11) in Tullahoma, Tennessee.


It is a super well designed one of a kind highly modified Glasair powered by a Subaru engine. It is the point leader by a wide margin not only of the sprint class but all classes experimental and factory. The liquid cooling system involves a large radiator in the aft fuselage and a belly scoop positioned like the one on a P-51.



Race Data ( the last two numbers are the speeds in Knots and MPH respectively:

2011 West Tesas 100 6/18/11 Sprint Glasair I RG Sherwood, Russell & Rhea 218.76 251.74
Indy Air Race 8/13/11 Sprint Glasair IRG Sherwood, Russell & Rhea 215.37 247.84
Memorial 130, Terrell, TX 5/28/11 Sprint Glasair I RG Sherwood, Russell & Rhea 214.18 246.47
Big Muddy, Carbondale, IL 6/4/11 Sprint Glasair I RG Sherwood, Russell & Rhea 212.71 244.78
Lone Star Air Rally 5/14/11 Sprint Glasair I RG Sherwood, Russell & Rhea 211.69 243.60
Rocket 100, 2010 11/20/10 Sprint Glasair I RG Sherwood, Russell & Rhea 210.72 242.49
Texoma 100, 2011 4/16/11 Sprint Glasair I RG Sherwood, Russell & Rhea 208.48 239.82
Taylor 150, 2011 4/2/11 Sprint Glasair I RG Sherwood, Russell & Rhea 206.01 237.07
BCAF 2011 4/30/11 Sprint Glasair I RG Sherwood, Russell & Rhea 199.01 229.02
Sulphur Springs 130 7/18/10 Sprint Glasair I RG Sherwood, Russell & Rhea 198.49 228.42
Grace Flight 2010 10/2/10 Sprint Glasair I RG Sherwood, Russell & Rhea 197.74 227.54
Taylor 150 4/11/10 Sprint Glasair I RG Sherwood, Russell & Rhea 189.05 217.55

So what does this have to do with RVs ... well it is a tricycle geared home built that is steared by the brakes on the ground just like our "A" model RVs. I have had the same failure in our RV-6A at a remote airport (Prescott, AZ) and only required a tow to the ramp where I used a rental car to get my necessary resources and repaired the broken line (at the flare) and reterminate at the cylinder. Here is the significant point - if you fly an RV with this kind of system you have to be prepared for this kind of failure. When it happens you will be applying a brake for a turn and the high pressure will break the weak point in the system. At this point you will feel the pedal give and you can no longer turn in the direction of the failed brake by using that brake. You still have the a limited ability to turn in the opposition with the opposite brake but if the nose wheel is turned more than the remaining momentum and rudder authority can overcome, the turn cannot be corrected. Anyway, when you have a brake failure on an "A" model it becomes a delicate situation and you have to be mentally prepared to use the limited resources left to bring the event to a satisfactory conclusion.

First of all, as has been said many times in the forum, use the rudder for turns and avoid dependence on the brakes for directional control as much as possible.

Second, think about this failure mode and how you will deal with it when it occurs so you don't have to formulate a plan real time.

Bob Axsom

More info

Message below from the Rhea half of the Russell & Rhea Sherwood team - Marilyn is the name of their airplane.

Bob Axsom

Regarding brake usage for steering - maybe some use it a lot, I don't. About the only time I ever use brakes for steering is when at extremely slow speeds (like 5 mph) when making acute turns, as in taxiways. At normal taxi speeds in my 6A of 12 to 18 knots, I never use brakes unless there is a significant crosswind. In those cases, speed is down in the 5 to 8 knot range, and a brake pulse is frequently necessary. They simply are not needed for directional control in most cases, as the rudder is enough. It is not uncommon to use full rudder when taxiing my 6A.

Very timely

This is a good message to remember. Brakes are important.

This is a timely message for me.
Today I flew out to the normal hamburger spot and on landing and taxi I noticed a slight pull to the right. I thought it was a cross wind, but then I checked the sock and it could not be the wind. I flew back home and pulled the wheel and brake off. When inspecting the brake I saw some very sticky black substance on the brake piston. It turned out to be a small leak in the o-ring causing the brake fluid to seep out, become sticky and bind up the piston. Because the piston could not easily retract, it was causing the brake to rub and subsequently make the plane turn right. It could have caused the brakes to over heat and possibly caused a fire. Glad it didn't.

I guess the lesson here is to pay attention to your plane and check when you feel something is wrong. And that breaks are important.

Don't break the brakes.

Coffee breaks are important, as are vehicle brakes.

Bevan

And That's the Way it is

Bob Axsom said:

Message below from the Rhea half of the Russell & Rhea Sherwood team - Marilyn is the name of their airplane.

Bob Axsom

Marilyn will not be racing any time soon. On our way to Tullahoma we made a
planned fuel stop at Tunica. The landing was perfect (according to the airport
staff that saw us touch down). However, that was followed by what I'll call an
"A ticket ride". The left brake failed (all steering on the ground is by
brakes) so we went off the runway into the grass. Using a little more right
brake, Russell avoided a runway light and shut down the engine. He couldn't
brake much or we would have hit a large concrete sewer cover. When we hit a
deep rut, the nose gear broke, two prop blades broke, the left gear collapsed,
and we ended somewhat nose down in the dirt. It all happened very quickly.
Fortunately, we were not injured. The Tullahoma Airport folks were great and
helped get Marilyn to a hangar where we are disassembling her to get her back to
Texas.

Rhea Sherwood​

Click to expand...

The sequence described here and my Prescott experience are so similar ...

I was turning off of the runway hot (yes showing off my skill???) when the right brake pedal went soft and I had a lot of momentum half way through the turn onto the narrow 90 deg. exit taxiway. I too was lined up for impact with a taxiway light and used the left brake for a quick deviation to the left of it and into the grass. Once there there is nothing to do but ride it out - thankfully there were no obstructions or ditches for me. One thing to remember is it is not safe to assume you can taxi back onto the paved surfaces. We had to lay down boards to get our plane back up onto the runway for tow to the ramp. The LG fairings don't like uneven surfaces.

Bob Axsom

I'm curious

Having flown my Aeronca Chief for a number of years with Goodyear cable actuated "pretend" disc brakes, I have learned that sometimes the only way to avoid the ditch is firewall it and fly the rudder.http://www.youtube.com/watch?v=m7eL82GtO5E&feature=related This is the only option with straight skis unless you are really slow. Seems like the wrong thing to do but really its the right thing to do. Will this work on the A models? Any one try it?

Something to consider in formulating one's plan

Andrew M said:

Having flown my Aeronca Chief for a number of years with Goodyear cable actuated "pretend" disc brakes, I have learned that sometimes the only way to avoid the ditch is firewall it and fly the rudder.http://www.youtube.com/watch?v=m7eL82GtO5E&feature=related This is the only option with straight skis unless you are really slow. Seems like the wrong thing to do but really its the right thing to do. Will this work on the A models? Any one try it?

Click to expand...

It is something to consider in formulating your plan for dealing with this failure. There are a lot of variables when it occurs and a skilled pilot that has experience with this method (practice) under the right circumstances might find this the best solution.

I am inclined to not introduce that dynamic to the situation with my airplane but that's just me.

Bob Axsom

There is an old dirtbike truism that may apply here: "When in doubt, gas it".

Never had an A model RV get away from me, but I learned very early on with the Hiperbipe that full throttle seems to fix just about any screw up (and I had plenty in the early days).

You will be better prepared mentally if you take the view that brakes are evil and will fail on you at the most inopportune moment.

Actual brake component failures are rather rare... it's usually the lack of maintenance or improper installation which is at fault (from what I've seen).

Any word on what caused the failure in this instance?

None that I know of

Walt said:

Actual brake component failures are rather rare... it's usually the lack of maintenance or improper installation which is at fault (from what I've seen).

Any word on what caused the failure in this instance?

Click to expand...

We did go over the cause of failures some time back but the cause of this particular failure is unknown at this time I believe and may never be known since the landing gear containing the failed brake collapsed. The most vulnerable brake is the right one since it is very easy to get on the right brake while applying right rudder on the takeoff roll. They can easily be worn out between annual condition inspections if proper technique is not used. In this case the left brake failed and since this is a retractable there are more failure modes to consider than on our RVs.

However, this thread is about what to do after the failure has occurred, when you have momentum trying to make you continue straight ahead, centrifical force trying force you out of any turn you might be in, a rudder (and other flight controls) with authority depending on natural or artifical wind, one brake, various surface conditions, various wind conditions, possibly visibility limitations and obsticals such as airplanes, lights, vehicles and structures. Sometimes you trade certain damage for the unknown - in this case the unknown was probably worse than hitting the light.

Bob Axsom

Toobuilder said:

There is an old dirtbike truism that may apply here: "When in doubt, gas it".

Click to expand...

ROTFLMAO.

That saved me more times than I can remember but it's certainly going to take some quick acting guts to do it in an airplane making a beeline for something hard. Sheesh!

It has been said that when presented with an emergency, sometimes the best course of action is to do nothing. While this is most certainly true, we are also charged as pilots with the requirement to evaluate a situation in a split second and immediately carry out the appropriate action. It's our job to know when to wait and evaluate, and when to take action. Sure, it may be counterintuitive to firewall the throttle when careening out of control towards that Gulfstream, but so is pushing the nose down when mushing towards rising terrain in an overloaded airplane, or keeping the "steering wheel" straight when a wing drops on a base to final stall. Heck, look how often a pilot forces a poor approach and landing when it should have been completely obvious that a go around was warranted. Some people have only one tool in their toolbox, and that's a dangerous situation.

I hear ya'
Having thought about the dirt bike mantra, I am formulating how and where to practice said single brake control maneuvers. Practice makes for quicker automated response.

Walt said:

Actual brake component failures are rather rare... it's usually the lack of maintenance or improper installation which is at fault (from what I've seen).

Any word on what caused the failure in this instance?

Click to expand...

I am new to this group and was reading through old posts. I realized that I had seen a video on this incident. I found that video on YouTube, here is the link.

http://www.youtube.com/user/ThrottleUpSVX

Pre-Flight

Just like the Grummans with an identical steering system, the pre-flight is important.

Check for ANY trace of brake fluid at the brake bleeder nipple. Even a minute trace should make the flight a no-go until a complete investigation.

Even though failures can occur elsewhere in the system, the wheel "end" seems to be the most likely culprit - check it before each flight...

Cause

I haven't seen this video for some time and it appears to have been edited with text and cause of failure at the end. It shows a separated brake line with a product name Nylaflow. In watching it and having been through on of these in our RV-6A this one looks like it should have been survivable but ... its easy to say if you weren't there. I suspect they will make some canges when and if they repair it - I assume they will but I know it is disheartening.

Bob Axsom

flyemlow said:

I am new to this group and was reading through old posts. I realized that I had seen a video on this incident. I found that video on YouTube, here is the link.

Click to expand...

Welcome to VAF, Kelly. As you've discovered, there's tons of great info in the archives. I hope you stick around to add to the super group of people here. Thanks for the video link.

--
Stephen

This is something that we need not wonder about -- we can just go and try it. That's precisely what I did.

I flew down to Madison, GA and performed several landings -- slightly uphill -- and was able to come to a complete stop on the runway each time without using any brakes at all. Of course this was with negligible wind.

I think where people get in trouble is when they hit the brakes -- and only one works -- and by the time you figure out what happened you're headed for the weeds.

"in this case the unknown was probably worse than hitting the light."

Runway/taxiway lights are installed using frangible (break at a certain point) coupling. I would prefer not hitting one with a prop but with a wheel or lower gear leg aircraft damage should be minimal.

Of course I did see one light hit at my airport where the light fixture became airborne and caused damage to the horizontal stabilizer.

I am glad our big rudder is effective down to 15 or 20 kts at idle. I do a brake check on final then again on rollout around 35-40 kts which should give me a little time and runway remaining if something fails. Another good reason to slow before the turnoff and not in the turn.