Can the Owner of a Certified Airplane Do Their Own Maintenance?

Answer: FAR 43.3 permits a pilot to perform preventive maintenance on an aircraft they own or operate, provided it is used strictly for noncommercial operations under Part 91, so no flight instruction or scenic flights.

Under Appendix A of Part 43, you'll find a list of preventative maintenance that can be done without supervision of an A&P mechanic. Much of it has to do with replacing something already installed. For example, the pilot/owner is allowed to perform tire changes, service shock struts, lubricate wheel bearings, and replace hydraulic fluid, side windows, lights, batteries, and tray-mounted avionics with the exception of transponders, DMEs, and autopilots. They can also replace, clean, gap, or rotate spark plugs, replace prefabricated fuel lines and nonhydraulic hose connections, and clean or replace fuel and oil strainers and filters.

If you are attempting this maintenance for the first time, it's a good idea to have an experienced aviation mechanic (A&P) by your side just to make sure you're doing it correctly, have the right tools, and don't accidentally wrench yourself into a corner.