Summary of Builder Error Accidents

[rwanttaja]

I stuck my nose into an anti-homebuilt cat fight in another forum, and ended up posting the attached list. Thought folks here would like it, too. It's a summary of homebuilt accidents related to builder error, from 1998 through 2012.

Ron Wanttaja

[1600vw]

When you say " Builder error" I expect to see things like wings falling off and such. Even though in fact a couple in the list did have this happen most where engine failures do to improper something or other. Builder error is kinda misleading. Sure you could say these things where not installed correctly, but they where not in fact built by the person building the airplane. These parts where just installed. So really this was an installation error.
Builder error again to me is something like the wrong epoxy was used, or the wrong material, or the wrong...get the idea.....

Tony

[rwanttaja]

When you say " Builder error" I expect to see things like wings falling off and such. Even though in fact a couple in the list did have this happen most where engine failures do to improper something or other. Builder error is kinda misleading. Sure you could say these things where not installed correctly, but they where not in fact built by the person building the airplane. These parts where just installed. So really this was an installation error.
Builder error again to me is something like the wrong epoxy was used, or the wrong material, or the wrong...get the idea.....

Tony
Good point, Tony, I use "Builder Error" as a kind of catch-all category. On occasion, I wade through the list and divide the mistakes into installation errors, workmanship errors, use of inadequate materials, etc. and also break down what aircraft system was affected. It's one of the things I show on my presentations to EAA chapters; I'll post a summary chart when I get home tonight.

It's always a tussle coming up with categories. Too few, and some items appear to dominate. Too many, and you end up with a lot of categories with only one or two cases and no way to make any sort of assessment.

For my Sport Aviation article this year, I actually expanded by old "Pilot Miscontrol" category into about eight separate sub-categories. I'm contemplating doing the same for "Builder Error" for next year's report.

Ron Wanttaja

[tspear]

When you say " Builder error" I expect to see things like wings falling off and such. Even though in fact a couple in the list did have this happen most where engine failures do to improper something or other. Builder error is kinda misleading. Sure you could say these things where not installed correctly, but they where not in fact built by the person building the airplane. These parts where just installed. So really this was an installation error.
Builder error again to me is something like the wrong epoxy was used, or the wrong material, or the wrong...get the idea.....

Tony

Wings falling off, engine failures, installation errors will in 99% of the cases be builder error. No idea how it can be otherwise. The only time the buck should get passed on from the builder is when there is a failure in the design or manufacturing of a sub-component which the builder did not assemble. Since the majority of the accidents are in aircraft based on popular designs (e.g. Van's RV) where the recommended engine and other sub-component are based on certified or have completed many installation it really does place the onus on the builder.

Tim

[1600vw]

Here is an example of builder error. This happened to be on my airplane.

Had my airplane in the shop the first winter I owned it. I was going over a lot of things and had all the panels off and cowl. My A&P walks by and spots that the builder of this airplane welded on the throttle cable. This weld held the end on the throttle cable that hooks to the carb. The A&P say's, I would install a spring on this for when this fails you want this to go wide open. I look up from what I am doing, look at this part, look at the A&P, shake my head and go back to work and forget all about this.

A month goes by and on take off one day guess what happens. That darn weld broke. I could hear my A&P's voice in my head as I am fighting a bad problem on take off.

I call this builder error. But of course I learned a lot more then that from this. I learned a lot. Our parents called it, learning the hard way. I hope not to learn this way anymore.

Tony

[rwanttaja]

I've attached a summary of Builder Error causes and affected systems. This is from a 2009 EAA presentation, so it has fewer cases. I think I probably will update it for next spring's article.

Many people think "Wings coming off" when they contemplate builder error, but as the attached chart shows, structural issues are a minority. A lot of that is due to the prevalence of fairly complete kits; it's hard to botch a wing spar when the spar comes completely assembled.

The biggest issue with builder error is getting the systems to work...the fuel system, the oil system, the reduction drive system, the control system, etc. There are a lot of tasks that need to be accomplished for the airplane to work, and too many builders skip steps or don't perform fundamental testing to verify things are done right. Note that problems with the fuel system or engine installation accounts for about two-thirds of the total builder error cases. In many designs, these details aren't covered as well as other parts of the airplane. The Fly Baby builder's manual, for instance, is about 260 pages long. The engine section is nine pages.

When you look into the cases, it's rare that a commercial component fails on its own. There's usually something related to mistakes the builder made.

Ron Wanttaja

[1600vw]

I like your work and the pie charts.

If someone leaves a nut loose or did not follow plans and did not install a washer or something like this I call this builder error. But if someone routed the exhaust to close to something and caused a fire I call that installation error. Or they cowled the engine in such a way as to burn the mag up from over heat, again installation error.

But to just label them all under builder error is not doing any good. If I was going from shop to shop and trying to improve safety, I would not group everything under one heading. Break it up into groups kinda like the pie charts, but do not label it, builder error, but errors in building an airplane. Not errors from those building the airplane. If you word it like this believe it or not ears will open and not close. People will even give idea's as how to improve. Its a matter of changing the way one thinks, not the way one is doing something.

Tony

[Sam Buchanan]

I like your work and the pie charts.

If someone leaves a nut loose or did not follow plans and did not install a washer or something like this I call this builder error. But if someone routed the exhaust to close to something and caused a fire I call that installation error. Or they cowled the engine in such a way as to burn the mag up from over heat, again installation error.

But to just label them all under builder error is not doing any good. If I was going from shop to shop and trying to improve safety, I would not group everything under one heading. Break it up into groups kinda like the pie charts, but do not label it, builder error, but errors in building an airplane. Not errors from those building the airplane. If you word it like this believe it or not ears will open and not close. People will even give idea's as how to improve. Its a matter of changing the way one thinks, not the way one is doing something.

Tony

As an EAA Technical Counselor I have gone "from shop to shop" many times in order to assist builders with remedying errors that can compromise safety and function. We never bother with semantics, just make a punch list of things that need addressing. If the builder had his hands on a component that can cause a safety issue, we discuss the situation and it is corrected by the builder. Whether or not it was "builder error" or "installation error" makes no difference, matter of fact I have never heard that distinction being made.

If I mess up the installation of a well-designed exhaust system, I get the blame...guess that would be builder error (since I'm the builder) if you want to stick a label on it. :)

Ron, your statistical work is very much appreciated. It points out why Tech Counselors devote special attention to inspecting fuel systems and engine plumbing/controls.

[1600vw]

A well designed exhaust or anything can be installed wrong without ever changing a thing. Then people start to call this well designed part junk when in fact it was installation error. I have seen this many many times in other fields, not aviation. But no difference. Like you said you screwed up an installation of something, you did not build, nor design said something you installed it wrong. Now in the shop looking at someones airplane you might get away with such broad strokes of a brush, but setting a group down and just talking, the broad stroke of a brush just does not do it. Will it work, yes, but not efficiently.

An exhaust installed wrong is not builder error. The airplane could have been built and flying for years, then someone buys this airplane and changes the engine but does it wrong, this is not builder error, but installation error.

Tony

[gbrasch]

Thank you Ron! This is great info and obviously you have put a lot of time into this. I have shared it with RV people on my site and of course gave you the credit. Glenn