Can I work on my own airplane without formal mechanic's training?

Question

Suppose I am not planning to be a career A&P mechanics, but would like to get some hands-on skills for airplane maintenance, for reasons of both cost and hobby. Say my basic goal is to perform tasks from as simple as tire replacement, instrument replacement to avionics installation and troubleshooting. My goals may be progressive. The aircraft for maintenance is self-owned or owned by share. The ownership and operation of the aircraft is within US.

Can I work on my own airplane? Since I'm not certified for mechanics work would it be OK that a certified A&P endorse my work is standard-compliant?

Answer 1

FAR Part 43 contains the information of what you can and cannot do to an aircraft and what requirements you must have.

If you are a certificated Private Pilot (as in not a sport pilot), there are quite a few things you can do to an aircraft you own, that is not used for commercial purposes. Like:

• Replace wheel bearings
  
• Remove/repair/reinstall wheels
  
• Replace safety wiring and cotter keys
• Service landing gear struts by adding oil/air
• Lubrication not requiring disassembly of non-structural items like cover plates, cowlings, and fairings
• Simple fabric patches not requiring rib stitching or removing structural parts or control surfaces
• Replenishing hydraulic fluid
• Refinishing decorative coating of fuselage and other parts
• Repairing upholstery without disassembly
• Simple repairs to fairings, etc
• Replacing side windows
• Replacing safety belts
• Replacing seats or seat parts with approved replacements
• Troubleshooting and repairing broken circuits in landing light wing circuits
• Replacing bulbs, reflectors, and lenses of position and landing lights
• Replacing wheels and skis where no weight and balance computation is required
• Replacing cowling not requiring removing the propeller or disconnecting flight controls
• Replacing or cleaning spark plugs and setting gap clearance
• Replacing any hose connection except hydraulic connections
• Replacing prefabricated fuel lines
• Cleaning or replacing fuel and oil strainers or filter elements
• Replacing and servicing batteries

And others Source

However, note that it has to be your airplane, and it can't be used commercially (which I think includes offering it for rent). There is very little you can do in the way of avionics (read #31 and #32 in the reference I gave).

The fun thing to note is that although a PPL is required, the PPL training does not give any special attention to any of these items, and therefore really somebody off the street is technically just as qualified as a private pilot, but the private pilot is the only one authorized to do the work (provided they own the plane). When I got my PPL, nobody walked me through replacing cotter pins or anti-back-out devices...

Edit These rules though may be different when you get into experimental category aircraft but I can't source it now and will do more research and edit when I can clarify.

Answer 2

Short Answer:

Yes, you can work on your own plane, if:

I. You are performing maintenance work under proper supervision, or

II. You are performing preventive maintenance, and each of the following are true:

1. You are a certificated pilot (except sport pilot),
2. You either own or operate the aircraft in question, and
3. The aircraft is operated under part 91.

Long Answer:

14 CFR 43 regulates aircraft maintenance for those aircraft with a U.S. airworthiness certificate, but not for experimental aircraft (see §43.1 Applicability). For the purposes of this answer, I will use the term "aircraft maintenance work" to refer to any and all maintenance work on U.S. certificated aircraft that might fall under the legal definition of maintenance, preventive maintenance, and alterations. This does not include inspections.

§43.3 regulates who is authorized to perform aircraft maintenance work. Aircraft maintenance work is subdivided into maintenance, preventive maintenance, rebuilding, and alterations. For the purposes of this question, we are interested in two of the many description of who may perform aircraft maintenance work.

The first is found in §43.3 (d), emphasis mine:

(d) A person working under the supervision of a holder of a mechanic or repairman certificate may perform the maintenance, preventive maintenance, and alterations that his supervisor is authorized to perform, if the supervisor personally observes the work being done to the extent necessary to ensure that it is being done properly and if the supervisor is readily available, in person, for consultation. However, this paragraph does not authorize the performance of any inspection required by Part 91 or Part 125 of this chapter or any inspection performed after a major repair or alteration.

In other words, anyone can perform aircraft maintenance work under proper supervision. In your case, if you are working under an authorized mechanic who properly supervises you and signs off the work, yes, you can perform aircraft maintenance work.

The second is found in §43.3 (g), emphasis mine:

(g) Except for holders of a sport pilot certificate, the holder of a pilot certificate issued under part 61 may perform preventive maintenance on any aircraft owned or operated by that pilot which is not used under part 121, 129, or 135 of this chapter. The holder of a sport pilot certificate may perform preventive maintenance on an aircraft owned or operated by that pilot and issued a special airworthiness certificate in the light-sport category.

This is more complex. If we are to assume that you are the holder of a pilot certificate issued under part 61—for example a Private Pilot certificate—then you meet that part of the qualification. If you own your own aircraft, in whole or in shares, then you also meet that part of the qualification.

Now, you may also qualify if you only operate the aircraft regardless of ownership. 14 CFR 1.1 defines Operate as follows:

Operate, with respect to aircraft, means use, cause to use or authorize to use aircraft, for the purpose (except as provided in §91.13 of this chapter) of air navigation including the piloting of aircraft, with or without the right of legal control (as owner, lessee, or otherwise).

_{(Note that §91.13 defines careless or reckless operation. In other words, if you use an aircraft carelessly or recklessly you are not actually operating it according to the legal definition and so do not have preventative maintenance privileges for that aircraft. Now you know.)}

So, if you own, pilot, or otherwise operate the aircraft, you may have preventive maintenance privileges. The final qualification will be whether you operate the aircraft under part 91—which would give you preventive maintenance privileges—or under parts 121, 129, or 135—which would generally deny you preventive maintenance privileges. Note that parts 121, 129, and 135 refer to scheduled or on-demand passenger or freight operations available to the general public, to put it simply.

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Now, some of the answers here imply that you are not authorized to perform preventive maintenance if the aircraft you own or operate is used for commercial purposes.

This is not the case.

Many commercial purposes are allowed under part 91, including rental, flight instruction, aerial patrols, sightseeing, business transportation (think business jets), skydiving, and glider or banner towing, among others. If you otherwise meet the above qualifications and operate an aircraft for such purposes, you are legally authorized to perform preventive maintenance.

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This leaves us with the question of what constitutes preventive maintenance. The legal list is found in 14 CFR 43 Appendix A (c) and other answers have done a good job of outlining that, so I won't go into it further.

Answer 3

Keep in mind you can work on your plane you own it and bought. It's yours, you can take cylinders off, poor sand down them, do whatever you want, it's your plane. HOWEVER, it's not airworthy once you do so, unless you are a certified mechanic or the work you are doing complies with what is allowed under preventive maintenance. Do whatever you want if you own it, just remember it's not legal or airworthy to fly after your done until an authorized person releases it back into service.