The science of building/maintaining aircraft

Building and maintaining aircraft is mostly science and perhaps a bit of art. There should be a keen awareness on the tradeoff made between affordability, suitability, and safety. If it’s a homebuilt and you built it, than who knows better than you on how to maintain it? That’s somewhat debatable and while the amateur-built regulations give us plenty of rope with which to hang ourselves, there are some best practices that should be taken as gospel. Many have been learned the hard way.

A few observations:

Hot Seat—Understanding amperage, circuit breakers, and good wiring technique is more than just a good idea. A homebuilt flying the Everglades some years ago in visual conditions asked ATC if they were aware of any fires in the area. ATC knew of nothing, but the pilots soon discovered that the automotive electric seats they had installed had turned into hot seats. Unfortunately, the plunge into the swamp was fatal and the NTSB noted that a circuit breaker supposedly protecting wiring and accessories from a short circuit, didn’t. We can discuss the wisdom of electric seats in homebuilts but wiring practices are really non-negotiable. It was high price to pay for a bit of ignorance.

Hose Clamps—Another fatal accident occurred when a mechanic decided to use an automotive hose clamp to secure a muffler and exhaust pipe on a Piper Cherokee, resulting in an in-flight fire. The aircraft version, while about 15 times more expensive, had a critical detail that the mechanic apparently overlooked or thought unimportant. There is a pin on the clamp, which is inserted into a hole in the muffler and exhaust pipe and holds the two together even if the clamp loosens. Some parts of aircraft really do need to be expensive and well-made.

Plumbing—A recent honest mistake apparently involved the builder of an RV-10 who suffered an engine stoppage due to fuel starvation. There is currently a $35 million lawsuit pending against Vans Aircraft and the manufacturer of the fuel flow transducer that the NTSB reported was plugged by an improperly-used sealant in the system. There was loss of life so the legal system is involved. Sometimes that’s warranted but this has little, if anything, to do with Vans in my view.

There is a long thread on Vans Air Force that looks at the pros and cons. One of the writers thoughtfully points out that there is perhaps not enough guidance on what and how one should specifically assemble various parts and pieces. In my two earlier examples, it seems the guidance was pretty clear and the crux of this suit may hinge on what the builder knew and when he knew it. How much guidance should a manufacturer for a kit or a component provide, and does that incur additional liability? Is it their responsibility to educate builders on everything that a certificated mechanic should know? Guess a jury will sort that one out.

One thread respondent points out that in too many cases there is “tribal wisdom” or the excuse that if the Framistan hasn’t failed in 350 hours it must be done right. Perhaps, but there are some notable examples of certificated aircraft where a rigorous process didn’t uncover a particular fault until years or decades later. Is that evidence of negligence?

I’ve had the honor of meeting with Dick VanGrunsven and you won’t find anyone more concerned about design, safety, pilot proficiency, judgment, ease of kit assembly, and the use of proven methods. There are thousands of Vans kits flying and he’s become one of the most successful manufacturers in the world.

But building and maintaining an aircraft is still a daunting task. The certificated manufacturers have to regularly defend against a variety of suits—most of which are groundless but very expensive. The “gotcha approach” once a suit is filed doesn’t always serve the industry or buyers of aircraft particularly well. An admission that something could be improved, such as more guidance or improving the hardware, is often used as evidence of wrongdoing when that isn’t usually the case.

This trial will be closely watched from many quarters. In the interim let’s insure that our machines are so well built (if we built them) and maintained that we’re willing to put our families into them. Don’t forget that flying part either.