Rudder Failure (Jam)

Low n Slow · #1 09-02-2007, 07:21 PM

I?m a new RV pilot with about 25 hours in the -4 I bought a 50% share in a few months ago.

Last week after making a good approach and 3 point landing, while rolling out I found I had no right rudder. As I was approaching the left side of the runway, I finally started to apply right brake, but not before my left main went off the edge of the runway. Luckily, there was no damage, except my embarrassment, but it could have ended very differently.

I think years of being warned about over braking just after landing for fear of nosing over (including just recently during my RV checkout), was a factor in my hesitation. Lesson learned, next time I?ll be much more aggressive and use the brakes as needed.

Later after checking and finding no problems or interferences with the tailwheel, control arm, chains, rudder horn or rudder stop and cable, I pulled the Avionics panel to check the pedals. The castellated nut on the bolt that acts as the right brake outboard clevis pin, had vibrated off. This allowed the head of the bolt to back out enough to hit the outboard edge of the right foot well (see photo) which prevented the rudder going beyond the center position. I haven?t had the chance to check other -4?s since this happened, but on ours there?s minimum clearance here. We noticed that on the left side it looked like that area was pounded outboard a little for more clearance, but this wasn?t done on the right.

After a careful search of the foot well and floor, I came up with the nut and washer, but no cotter pin. Let me say that we?re very happy with the overall workmanship on this plane, and I don?t regret for a minute buying an experimental as flying it has been one of my greatest pleasures since I started flying. But almost everyone I tell this story to seems to have the same thought, ?What other cotter pins are missing?? Of course this in an area that once assembled, is very hard to see and inspect.

I?ve been flying certified aircraft since 85?, approx 960 hours (all but about 200 in taildraggers) without any major systems failure, yet in only 25 hours I?ve had this and a complete left brake failure (total loss of fluid) that I caught during a pre-flight. As my mechanic said, ??welcome to the world of experimental aviation!? There are so many little items that can ruin your whole day if overlooked this is a great example of that famous saying about the unforgiving nature of aviation.

Hopefully this story can benefit those building, inspecting and for those like me, who?re transitioning from the certified world looking to buy a flying RV.

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Tom
RV-4
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cjensen · #2 09-02-2007, 07:55 PM

Wow! Glad to hear there was no damage Tom! Good info for the tandem RV's!

G-force · #3 09-02-2007, 09:32 PM

Sounds like a good wakeup call to go over every single nut, bolt, jam nut, cotter, and whatnot and give it a good once over. Since you didnt build the plane, alot of this stuff you will be seeing for the first time. Get familiar with all the "nuts and bolts" of the plane, expecialy the important flight controls ones. There are some cotters I would really want to inspect at this point, like on the elevator and aileron push rod and such.

pierre smith · #4 09-03-2007, 05:15 AM

Tom,
From your picture it looks as though you have a nylok nut on the two steel plates that attach the cable to the pedal. This should be a castellated nut on a drilled/cotter-keyed bolt.
Whenever a bolt is a hinge pin, it should be a cotter-keyed situation. On the elevators and rudder hinges, the ball end is the pivot, not the bolt so there we use nylok nuts.

Glad you saved it,

Pierre

cytoxin · #5 09-03-2007, 05:53 AM

do a thorough 100% (what i call it ) and ease your mind... good luck.
they do make castellated nylocks...

Tom Martin · #6 09-03-2007, 07:44 AM

Tom
Van has a service notice relating to this issue http://www.vansaircraft.com/public/notices.htm
It is down the list a ways under RV4. Slop in the upper bolts where the rudder pedals attach to the firewall can also allow enough side to side movement of the pedal to catch at this location. A few directed blows with a ball peen hammer in this location will help in giving a bit more clearance for the bolt head.

aerial · #7 09-03-2007, 11:04 AM

I purchased a poorly built experimental and it took over 6 months to get it airworthy. "Deals" are not what they appear to be many times. At your pre-buy or annual condition inspection this would have been an area that was checked. If you have not completely gone over all the flight controls, fuel system, and engine, I highly recommend it.

rvbuilder2002 · #8 09-03-2007, 10:57 PM

Quote:

Originally Posted by Low n Slow

As my mechanic said, ??welcome to the world of experimental aviation!?

Glad to hear everything turned out ok but I just have to make a comment about the above statement.
I have been an A&P for 14 years, working with certificated and experimental aircraft.
I have seen stuff on certificated aircraft that would make the hair on the back of your neck stand up.
Airplanes are airplanes. It doesn't matter if it has an experimental sticker on it. Any of them can hurt you (or worse).

This brings up another point that is sort of related...
The condition of any RV should be highly suspect until you have proven to your self that it is not.

For example... I am now flying an RV-6A that I did major repairs on because of a landing accident while piloted by the previous owner. Every skin on the fuselage except the two top turtledeck skins have been replaced. So as you can imagine I got very deep into the insides of the airplane. I could write a book about the problems and construction errors I found. So I can honestly say that it is better (Much) than new. It has no bondo, anything that had any damage or was questionable got replaced. Including a total engine teardown inspection (airplane only had 44 hours since first flight).

Here is the sad thing...If/when I decide to sell it, it will have a bad mark against it (two full pages of stuff in the log book describing the repairs).
It took me more than a year to make it fly again and in reality it is more like I completed a project started by someone else (and fixed everything wrong before flying it). Many potential buyers will not even look once they find out it has a damage history. Instead they will buy the one with the fancy paint job and loads of stuff in the panel. It may look good on the out side, but on the inside it may be a nightmare.

No...I am not trolling for a buyer, but I do have 18 years experience working with RV's, I have done lots of prepurchase inspections, and first fight inspections.

I am just hoping that people considering an RV purchase will be careful.

briand · #9 09-04-2007, 09:51 AM

Quote:

Originally Posted by rvbuilder2002

I could write a book about the problems and construction errors I found.

Here is the sad thing...If/when I decide to sell it, it will have a bad mark against it (two full pages of stuff in the log book describing the repairs).

I am just hoping that people considering an RV purchase will be careful.

Could you list a few examples of the errors you found? Just curious.

Low n Slow · #10 09-04-2007, 12:20 PM

Quote:

Originally Posted by pierre smith

Tom,
From your picture it looks as though you have a nylok nut on the two steel plates that attach the cable to the pedal. This should be a castellated nut on a drilled/cotter-keyed bolt.
Whenever a bolt is a hinge pin, it should be a cotter-keyed situation. On the elevators and rudder hinges, the ball end is the pivot, not the bolt so there we use nylok nuts.

Glad you saved it,

Pierre

Thanks Pierre and everyone who responded.

All the nuts on the pedals are castellated, but the ones that attach the steel plates to the cable are nylok nuts. Does anyone know if this is the standard setup?