5/20/2007

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I am writing this description of my first flight several months after the fact. No, I am not psychologically traumatized - I just wanted to spend my time fixing the plane rather than maintaining this web site.

The short version of what happened is my right tire was completely flat when I landed. The plane left the runway and flipped.

I installed the wheels and tires many months before the flight. During construction the plane sat on the wheels and I rarely had to add air. During taxi tests I never had to add air. The night before the first flight the right wheel was low so I added air. The morning of the first flight we noticed it was again low and again we added air. Alarms should have gone off in my head. When I took off I felt a slight forward lurch. I attributed this to unintentionally riding the brakes. I came in for landing a bit faster than normal (which was said to look normal from the perspective of the folks on the ground) and did a wheel landing. Immediately it yawed really hard to the right. As I said full opposite brakes and rudder did not stop the turn. The prop dug into the dirt and the plane did a start of a ground loop and flipped at the same time.

The canopy split open like an egg and I was able to crawl out. I had cuts on my arms and legs from the Plexiglas but other than that I was uninjured. I wore a helmet which prevented cuts on my face and head.

After leaving the plane I stood up and waved to let my wife know I was OK and then went straight to the right wheel. The tire was flat. After things settled down a little (a rescue team and ambulance were there almost immediately), an A&P present received permission from the FAA representative on the scene to replace the tire while the plane was inverted so that we could eventually tow the plane back. He leak tested the tube and found a pin hole in the side. The pin hole seemed to seal itself until pinched. The tube was not rotten nor was the hole anywhere near where it could have been pinched by the wheel halves.

The fire fighters recommended and I called a heavy duty wrecker to right the plane. The wrecker righted it by attaching a strap to the back part of the fuselage. Another strap was attached to the prop. When the plane was lifted from the tail a rescue truck pulled the nose out from under to get the plane upright. Very surprisingly, there was no damage from this operation.

The damage from the accident was a bent prop, smashed windshield and canopy bubble, bent VS, bent rudder and both elevators were bent near the counterweights. The left wing tip was crushed as was the leading edge skin, landing lights and two ribs. Some rivets popped out on the right side of the instrument panel and both angles that attach the instrument panel to the side rails were bent. The spinner held its shape but has cracks in the fiberglass. What is surprising is the structural components (fuselage, wing spars, etc.) were intact. Who would have thought the tail would look as good as in the picture above after being slammed upside down and then picked up the way it was. As I write this, I have built and installed a new empennage kit and replaced all other damaged parts except for the engine. The crankshaft just completed an inspection in Oklahoma and should be on its way back.

On the defective tube, it was what was shipped to me with the kit. Most of the markings were rubbed off except for part of a "Made in Mexico" stamp. I have no idea what brand it was but I have now switched to Michelins.

What did I learn from this expensive lesson? I have given this a lot of thought. The flat tire left a skid mark all the way back to where the plane touched down. I would not have expected this. Yes, there should have been a lot of drag but not skid like that. It is very possible that even though I did not think I was on the right brake that I really was. Maybe light pressure on the right brake combined with the flat tire was enough to get it to skid. Maybe pushing down really hard on the left brake causes the right brake pressure to be applied by the other foot. I don't know.

So there are three lessons in this for me:

1. Tire pressure should not be treated lightly.

2. Keep feet off of brakes.

3. The RV8 is a really strong airplane

Update 3/19/2008: I have about 50 hours on N188LC and have made somewhere between 150 and 200 landings in it. With this acquired wisdom I now look back and say nothing good is going to come out of a flat tire on landing. The choice is to womp on the opposite brake and risk a prop strike or let it ground loop and risk a landing gear collapse. Or do what I did and do a prop strike, ground loop and flip over combo. I think luck has a lot to do with events like this. I was unlucky that it happened but very lucky not have been hurt and the plane to have been easily repaired.