And there's more. One has to know the regulations or you're in trouble real quick. Airworthiness Directives must be tracked and kept up-to-date and performed properly. Service bulletins, maintenance manuals for the airframe, engine and prop. Keeping those databases updated. Then there's the POH or AFM, a legally-required document that also has to be kept updated. STCs. Checking the TCDS sometimes. Service Difficulty Reporting. One must be able to do all that, know what is and what is not legally necessary, what should be done with some of the stuff that isn't legally necessary. None of it it has anything to do with wrenching experience on any motorbike or car or boat.
Here's an example of the complexity of it all. Some of it applies only to larger or more complex aircraft, especially things like pressurization (there are a few pressurized light aircraft), AC power generation and distribution (400 Hz, not 60), and turbines, but it all gets covered in formal training programs. Canadians are expected to have logged 70% of the
applicable tasks for the category of license applied for, and there are four categories here. There is a lot of overlap in those categories, so a quarter of the list is not acceptable. You need 70% of a big chunk of it, and those tasks must be done on your own, involving finding and using the data, selecting the tools and doing it right. No help.
https://www.aviationmaintenancejobs.aero/aircraft-ata-chapters-list
I tried copying and pasting the list, but it's too long. We're limited to 10,500 characters or something. Check it out.
Even at that, Canada has an Owner-Maintenance category of aircraft registration. It's limited to older, simple airplanes, and more than a few of the eligible airplanes have been transferred to it. Yet many of those owners get an AME to do much or all of the work, once they find that it's not nearly so simple. And maybe after they scare themselves once or twice.
There was a thread on POA regarding an accident a few months ago. The widow said that her husband "did a lot of his own maintenance." Red flag, that.