See thread title. That’s about it.
Enough to top up oil and pump up the tyres. About the same as a car owner needs.
You have to be good enough to know a problem when you see one. Visual inspections are important, and being a mechanic (knowing how to fix something) can’t hurt.
Depends on how much $$$ the pilot has to ensure some one else knowledgeable and reliable will do it instead.
With narrow exceptions, you actually need an entirely separate license to perform maintenance on an airplane, and it’s fairly rare for pilots to have one since it has substantial requirements on its own.
So, you don’t need to be a mechanic at all, and even if you are a mechanic, you’re not necessarily allowed to work on your plane even if you want to!
You are required to inspect the plane prior to flight, which generally means checking the oil level, fuel level, tire pressures, and general condition of all the visible components. That is the extent of the mechanical skills required.
I always wondered how satisfied I can be that the airplane will fly and hold together after checking the visible parts, when there are also so many not-so-visible parts that I can’t check.
Okay, so I’ve done my preflight. I know that all the visible hinge-pins are there. I’ve checked the oil. I’ve dumped a bit of gas from the sump. I’ve checked that some visible parts of the control cables aren’t frayed.
So how do I know the cables aren’t frayed where I can’t see them. How do I know all the connector rods and linkages and hinges and cotter pins are all still good in all the places I can’t see?
It always seemed to me that a pre-flight inspection just scratches the surface.
It’s not a hypothetical concern. One loose bolt in some place you can’t see, and a wing might fall off at altitude. I knew a glider pilot who crashed and died because that happened.
Try doing a walk around on a passenger jet with wings you can’t touch and can only see the underneath of. Ultimately you have to check what you can as well as you can but trust that the people who are able to check everything else, have done their job properly.
That’s why AC have scheduled inspections at so many hours of engine run time and hours of flight time. After an engine has run it’s allotted hours, it’s removed from the airframe and rebuilt.
My dad owned, flew, and maintained the old WW II trainer planes as a hobby. Ryan PT-22, Fairchild PT-26 and his great and grand showpiece, the Stearman N2S3. A 10th grade graduate who sold tools for a living, he did most of the mechanical maintenance on 'em. But he was no fool, when he felt out of his depth, he’d bring in a certified A & E person.
Damn, I miss those days punching holes in the clouds with him.
See, that’s one thing I like about helicopters. Everything is exposed. 
It that true for private aircraft, or only commercial?
ANSWERS FOR PILOTS: PREVENTIVE MAINTENANCE WHAT CAN A “DO-IT-YOURSELF” PILOT DO?
The link is to an AOPA article from June, 2012.
A private pilot does not need to be a mechanic, but a private pilot needs to have enough mechanical knowledge to perform a pre-flight and keep an eye for problems while flying.
Some private pilots go beyond the minimum. They certainly could get their AP certification allowing them to make repairs, but it’s a significant investment of time, money, and effort and most do not.
True for both.
The biggest exception is homebuilt aircraft - the FAA is willing to allow someone who builds an aircraft to do maintenance and repair on that one particular aircraft. But that’s yet another investment of time, money, and energy on the part of the pilot/builder.
AFAIK - may be different from Canada to USA - you can do any maintenance you want on an aircraft, provided the maintenance (beyond fill up, top up oil, and tire pressure) is then certified by a licensed Aircraft Mechanic. Beyond the basics it’s probably a good idea to leave it to someone who knows what they are doing.
Some things are done better and different than on a car, since you cannot pull over to the shoulder if something fails in flight. For example, many bolts are not only tightened but then have a wire twist to hold the bolt on (like a cotter pin) and for smaller planes, checking the state of cotter pin wires is a good idea when doing a walk-around. Also you don’t just grab some bolts and sheet metal from Lowes to fix your plane - aircraft parts are specific, have to be approved parts, and the manufacture process is held to standards that mean you should not get any 1-in-100 defective parts prone to cracking. Some aircraft bolts are hollow-filled with dye so cracks are colorfully apparent.
What about fraying wires? The other thing about an certified mechanic is they work by the book during the regular inspections (100 hour or annual for private planes, 50-hr of flying time for commercial) to look at things that experience and manufacturer recommendation have noted as important. If someone’s wing falls off or a control wire frays and breaks before such failures are expected, the maintenance and also special emergency inspections will specifically target those points from now on - “inspect wing roots for beginning cracks at such-and-such a point”. Since small plane designs are remarkably conservative, a lot of past experience will dictate when parts are liable to fail and they will be inspected for signs long before that. The FAA also publishes regular notices of mandatory fixes that must be applied to certain models to address concerns.
Yes, that’s allowable in private aviation in the US, but the trick is finding a certified mechanic to sign off on your work. Once they do that they’re legally on the hook for what was done so any mechanic worthy of the name is going to have a very, very high standard for applying a signature to your work.
Nothing wrong with the answers to date.
Note that aircraft owners may work on their own airplane. Pilots (as pilots) can’t. And the OP asked about pilots, not owners.
IOW, as a pilot with no mechanic’s license I can fix mine, you can fix yours. For the simple list of fixes in the AOPA article cited above.
But I can’t fix yours nor you mine. Nor can I fix one I’m renting, borrowing, etc. Even wielding a screwdriver on a loose panel fastener on a non-owned airplane is legally perilous. The only fasteners non-owners can touch are the ones (e.g. Dzus) fasteners, that don’t need a tool.
ISTM a private pilot needs to be enough of a mechanic to:
- Know how an aircraft engine works;
- Use that knowledge to detect problems inflight (or before launching);
- Know how to check the oil, and add oil if necessary;
- Know how to check the tension and condition of belts (alternator belt, helicopter clutch belts);
- Know how to check linkages and hinges.
Really, your typical private pilot will only act as a ‘mechanic’ when he or she adds oil. The other things are diagnostic, and the pilot should alert an A&P.
This isn’t quite correct. Anyone (and their dog) can do maintenance on a homebuilt aircraft (in the US, don’t know rules elsewhere). What the repairmans certificate allows you to do is the yearly “condition inspection” on an aircraft that you built. As you note, that is one license for one person per aircraft.
When I owned a share in a plane someone else built we could do anything we wanted to maintain it (I repaired a fuel tank leak and replaced the landing gear bungees) but every year had to hire an A&P for the condition inspection.
On the plane I built I can also do that inspection myself (but have hired an A&P to help with the parts I wanted to learn more about).
Fair enough - the rules on these things rapidly become complicated but yours was a better summation than mine was.