Preventive Maintenance Dos and Don’ts
Pilots and aircraft owners are allowed to perform quite a few maintenance tasks on the aircraft they fly. A full list of what the FAA allows can be found in 14 CFR Part 43 Appendix A, Paragraph (c). Many of the tasks can safely and easily be performed by handy individuals. However, below I’ll highlight some pitfalls to be aware of.
Personal maintenance cannot involve complex assembly, which, unfortunately, is left undefined by the FAA. Also, just like a mechanic, you are required to do the work in accordance with the latest manuals (you do have the latest revision of your aircraft’s MX manual, don’t you?), and you must ensure that all your tools function accurately and properly (which means calibrated, in FAA-speak). All parts installed on certificated aircraft must also be certified aircraft parts or made to aerospace standards, even screws and washers. So no running to a local or national hardware store for fasteners. Speaking of fasteners, item 26 says you are allowed “Replacement or adjustment of nonstructural standard fasteners incidental to operations.” Do you know how to differentiate between structural and nonstructural fasteners? For one thing, bolts are a no-go, but screws can get tricky.
For example, many Piper models have metal fuel tanks that screw into the leading-edge area of their wings. There are 70 screws per tank, and they tend to rust once the paint gets chipped off. Owners like to replace them with shiny, stainless steel, truss head AN526 screws. They look great, it’s easy to do, and why pay a mechanic for an hour of work just to replace screws? The problem is, the Illustrated Parts Catalog (IPC) lists those as MS27039 screws. Those are structural screws and are about 3x stronger than the AN526 screws. It turns out that once installed, the fuel tanks are an integral part of the wing’s load-bearing structure, plus they’re holding around 200 pounds of gas. Not only is the pilot/owner not permitted to change the screws, but they unknowingly weaken their wing structure by installing the wrong screws.
When in doubt, please, ask a mechanic. Here at Sweet Aviation, our technicians are more than happy to help provide professional advice. We love planes just as much as you do and will be glad to give you some advice or arrange a training session to teach you some simple, and legal, preventive maintenance services. This may or may not be a cheaper way to maintain your aircraft, but you are guaranteed the enjoyment and added value of learning more about your aircraft while spending some quality time with it in the hangar prior to launching into the friendly skies.