The Performance Standard
FAR Part 43 is titled "Maintenance, Preventive Maintenance, Rebuilding and Alteration." Portions of the 17 paragraphs and six appendices in this part specify who can do what types of maintenance, the definitions of major and minor alterations and repairs and what's required as far as record-keeping after maintenance. One of the most important paragraphs is 43.13 — "Performance Rules."
This paragraph says that work must be done using methods, techniques and practices prescribed in the manufacturer's maintenance manuals or other approved data. It also says that each person doing work on an airplane shall do that work in such a manner and use material of such a quality that the condition of the work shall be at least equal to the original condition. What's that mean?
Let's say Joe Owner decides to change a nose landing-gear tire, a task that's permitted under the PM rules. Upon reviewing the tire-changing tips in the FAA-approved aircraft maintenance manual, he learns that during the wheel reassembly operation, the bolts securing the two wheel halves must be retorqued to 90-inch pounds. To comply with the maintenance standard, Joe must have access to a calibrated torque wrench. Wheel half bolts are loaded in shear; this application does not require clamping (tension) loads.
During the inspection phase of the tire change, Joe finds that one of the wheel half through-bolts is severely rusted; can Joe boogie down to the local hardware store for a replacement bolt? No way. The replacement bolt must be identifiable as an aircraft-quality part.
The two examples are cited to show that a high standard of performance must be maintained. Few owners have enough experience in the aircraft-maintenance world to perform these tasks without coaching. That's where the benevolent dictator-style mechanic comes in.
He's your mentor. If you learn well and pay attention, it won't be long before you're trusted with more technical tasks. Aircraft maintenance is not rocket science — it's really a balancing act between doing no harm and efficiently troubleshooting and making repairs. Coaching is needed because airplanes are a curious mix of toughness required to fly for thousands of hours and areas so breakable that a misplaced hammer blow or an over-torqued fastener will result in damages that require hundreds of dollars and hours of labor to repair.
Many owners who begin learning PM tasks soon find that they enjoy and want more of the sharply defined what-you-see-is-what-you-get world of aero maintenance. Indeed, according to Part 43.3 paragraph (d), any person working under the supervision of an A&P (or other holder of a repairman certificate) may perform any task that the supervisor is authorized to perform, if the supervisor observes the work to the extent necessary to ensure that it's being done properly. It's not uncommon for competent owners to do almost all the tasks in an annual inspection.
Doing your own maintenance is not nonstop fun; broken fingernails, head dings from standing up too quickly under a prop and a fine lattice of safety-wire cuts on each hand top the list of drawbacks. But to many owners, these are less worrisome than the burden of "signing off" PM tasks.
The FAA wants signoffs in the airplane records after maintenance. Part 43.9 says entries must consist of a description (or reference to data acceptable to the FAA) of the work performed; the date the work was completed; and the name, type of certificate and certificate number of the person completing the maintenance.
Let's be clear on this data-entry business. The entry applies only to the work performed. If a tire was changed, the tire change is the only thing the signoff covers.
Here's an example of an acceptable entry for a main tire change.
November 15, 2010: Replaced the main tire (6.00 x 6, 6 P.R.) and tube (6.00 x 6) in accordance with (often abbreviated as I/A/W) chapter 32-40-01 and 32-40-02 in Mooney M20K maintenance and M20K parts manuals.
There are other money-saving resources for aero-maintenance neophytes. The best low-cost sources of inspiration and technical knowledge are type clubs. In exchange for a nominal yearly fee, aircraft owners can get on the Internet — from almost anywhere — and gain access to vast accumulations of model-specific and task-specific technical information. There's either a type club or an expert for almost every popular aircraft still plying the skies.
If you want to learn more about aero maintenance, I recommend getting on Amazon or any used-book site and searching for the out-of-print books in the Light Plane Maintenance Library series. Kas Thomas and other editors at Light Plane Maintenance authored the series. A good starting place is Rules and Inspections.
Maintenance-related books can also be purchased at avwebbooks.com.
One last word on this subject. One of the most grievous and dangerous errors owners make when they start to do their own maintenance is failing to understand how important it is to get their work inspected. The cornerstone of aircraft safety is redundancy — the "second set of eyes" inspection principle is a non-negotiable one.
Get your training, stay disciplined, get help when you need it and stay safe.
Go to airweb.faa.gov for a list of the FAA's preventive-maintenance tasks.