Can I do my own airplane maintenance?
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Answered By AOPA
Can I do my own airplane maintenance?
7 Replies
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AOPA Staff Answer
You can perform certain maintenance operations. They are listed under Appendix ""A"" of FAR43.
(c) Preventive maintenance. Preventive maintenance is limited to the following work, provided it does not involve complex assembly operations:

(1) Removal, installation, and repair of landing gear tires.

(2) Replacing elastic shock absorber cords on landing gear.

(3) Servicing landing gear shock struts by adding oil, air, or both.

(4) Servicing landing gear wheel bearings, such as cleaning and greasing.

(5) Replacing defective safety wiring or cotter keys.

(6) Lubrication not requiring disassembly other than removal of nonstructural items such as cover plates, cowlings, and fairings.

(7) Making simple fabric patches not requiring rib stitching or the removal of structural parts or control surfaces. In the case of balloons, the making of small fabric repairs to envelopes (as defined in, and in accordance with, the balloon manufacturers' instructions) not requiring load tape repair or replacement.

(8) Replenishing hydraulic fluid in the hydraulic reservoir.

(9) Refinishing decorative coating of fuselage, balloon baskets, wings tail group surfaces (excluding balanced control surfaces), fairings, cowlings, landing gear, cabin, or cockpit interior when removal or disassembly of any primary structure or operating system is not required.

(10) Applying preservative or protective material to components where no disassembly of any primary structure or operating system is involved and where such coating is not prohibited or is not contrary to good practices.

(11) Repairing upholstery and decorative furnishings of the cabin, cockpit, or balloon basket interior when the repairing does not require disassembly of any primary structure or operating system or interfere with an operating system or affect the primary structure of the aircraft.

(12) Making small simple repairs to fairings, nonstructural cover plates, cowlings, and small patches and reinforcements not changing the contour so as to interfere with proper air flow.

(13) Replacing side windows where that work does not interfere with the structure or any operating system such as controls, electrical equipment, etc.

(14) Replacing safety belts.

(15) Replacing seats or seat parts with replacement parts approved for the aircraft, not involving disassembly of any primary structure or operating system.

(16) Trouble shooting and repairing broken circuits in landing light wiring circuits.

(17) Replacing bulbs, reflectors, and lenses of position and landing lights.

(18) Replacing wheels and skis where no weight and balance computation is involved.

(19) Replacing any cowling not requiring removal of the propeller or disconnection of flight controls.

(20) Replacing or cleaning spark plugs and setting of spark plug gap clearance.

(21) Replacing any hose connection except hydraulic connections.

(22) Replacing prefabricated fuel lines.

(23) Cleaning or replacing fuel and oil strainers or filter elements.

(24) Replacing and servicing batteries.

(25) Cleaning of balloon burner pilot and main nozzles in accordance with the balloon manufacturer's instructions.

(26) Replacement or adjustment of nonstructural standard fasteners incidental to operations.

(27) The interchange of balloon baskets and burners on envelopes when the basket or burner is designated as interchangeable in the balloon type certificate data and the baskets and burners are specifically designed for quick removal and installation.

(28) The installations of anti-misfueling devices to reduce the diameter of fuel tank filler openings provided the specific device has been made a part of the aircraft type certificiate data by the aircraft manufacturer, the aircraft manufacturer has provided FAA-approved instructions for installation of the specific device, and installation does not involve the disassembly of the existing tank filler opening.

(29) Removing, checking, and replacing magnetic chip detectors.
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I think most owners are aware of the items in Appendix "A" of FAR43, however most are probably not aware of the FAA letter FAA Interpretation from the Chief Counsel's office, the interesting paragraph (page 2 second paragraph, in its entirety)

Many preventive maintenance tasks are listed in 14 C.F.R. part 43, appendix A, paragraph(c). The paragraph sets forth in 32 numbered sub paragraphs items the FAA has determined to be preventive maintenance. Even though the introductory text of sub paragraph(c) states that "[p]reventive maintenance is limited to the following work...." (emphasis added), in view of the broader definition of preventive maintenance in section 1.1, we believe that such limitation 'is not controlling. Similarly, for the same reason, we also believe that the following sentence in Advisory Circular 43-12A, Preventive Maintenance (which was referenced in Mr. Hernandez's letter), is overly restrictive. That sentence, found in Paragraph 3(b)(1), states: "If a task or maintenance function does not appear in the list, it is not preventive maintenance." As with the other paragraphs of Appendix A (i.e., on major repairs and major alterations), the lists are better viewed as examples of the tasks in each category - they cannot be considered all - inclusive. There are, no doubt, many "simple or minor preservation operations [tasks]" and many "replacement[s] of small standard parts not involving complex assembly operations "performed daily, especially on small general aviation aircraft, that the agency would consider to be preventive maintenance, though they are not included in the 32 listed items. It is our understanding that Flight Standards 'Aircraft Maintenance Division is planning to clarify this issue in a future revision to the AC.

{bold/underline emphasis is mine}

Reading appendix A item 1 the FAA says that I can perform "Removal, installation, and repair of landing gear tires"  and Item 4 "Service landing gear wheel bearings, such as cleaning and greasing."

I don't know how many people here have replaced their main landing gear tires or removed the bearings (inner and outer) for cleaning and regreasing however on my airplane in order to accomplish this task I must disassemble the brake caliper to release the wheel from the aircraft, and in my case the brake pads aren't riveted to the backing plates, they are connected via "button" and simply snap into place, plus to seperate the wheel halves I have to remove the brake disc/rotor as it is held in place with the same bolts that hold the wheel halves together.

So based upon the interpretation in the FAA's letter I believe I am comfortably within the guidelines of replacing the brake pads and the brake disc when replacing a landing gear tires. Since the FAA has already said I can do the tires and every GA aircraft with disc brakes would have to be disassembled I would thing the FAA would have consider this to be an owner performable maintenance item.

Oh and completing the job I have to safety wire the bolts on the caliper which is item 5 on the list "Replacing defective safety wiring or cotter keys"

Am I off the mark on this one?  I don't think so, I already working with the sub assembly that the FAA has already deemed to be a maintenance item, I'm just adding the stuff I have to remove to get to the maintenance item.

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Not to mention that "can" and "may" are different issues.  Not only must it be permissible by the regulations, but you also must have the knowledge and skill to do so.  For a lot of us, that means getting a licensed mechanic to teach us the procedure and observe our performance of it before we do it on our own.
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Ronald Levy:
Not to mention that "can" and "may" are different issues.  Not only must it be permissible by the regulations, but you also must have the knowledge and skill to do so.  For a lot of us, that means getting a licensed mechanic to teach us the procedure and observe our performance of it before we do it on our own.

Let us assume I have the knowledge to do the work I'm looking to perform competently, eg taught, shown, performed the work previously under the supervision of an A&P etc...  So am I reading the FAA interpretation of the rules correctly in that replacing the brake pads would fall under owner allowed maintenance?  I would think so.

Removing the brake caliper completely would be a no no as hydraulic lines are expressly forbidden and the brakes are hydraulically operated.  I'm sure you can make an argument that the FAA was referring to high pressure hydraulic lines, eg those operating gear retraction pistons, but I can see opening the the hydraulic line would introduce air that would have to be bled out, and although I'm capable of doing it, I would think this would not fall under the maintenance guidelines.

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Jeffrey Ross:
Ronald Levy:
Not to mention that "can" and "may" are different issues.  Not only must it be permissible by the regulations, but you also must have the knowledge and skill to do so.  For a lot of us, that means getting a licensed mechanic to teach us the procedure and observe our performance of it before we do it on our own.

Let us assume I have the knowledge to do the work I'm looking to perform competently, eg taught, shown, performed the work previously under the supervision of an A&P etc...  So am I reading the FAA interpretation of the rules correctly in that replacing the brake pads would fall under owner allowed maintenance?  I would think so.

Removing the brake caliper completely would be a no no as hydraulic lines are expressly forbidden and the brakes are hydraulically operated.  I'm sure you can make an argument that the FAA was referring to high pressure hydraulic lines, eg those operating gear retraction pistons, but I can see opening the the hydraulic line would introduce air that would have to be bled out, and although I'm capable of doing it, I would think this would not fall under the maintenance guidelines.

Except on my Grumman Tiger, you can change the brake pads without disconnecting the brake lines.  This is why the FAA took the view that something which is legal preventive maintenance on one plane might not be on another.  One has to examine the entire process to make the determination.

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Ronald Levy:

Except on my Grumman Tiger, you can change the brake pads without disconnecting the brake lines.  This is why the FAA took the view that something which is legal preventive maintenance on one plane might not be on another.  One has to examine the entire process to make the determination.

didn't say I had to disconnect the calipers (although I have under the A&P's supervision to rebuild them), I just said that removing it would be a no no without proper "supervision"

Other than trying to be dissuaded, I think the example I provided certainly falls under the guidelines of owner preventative maintenance.

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Jeffrey Ross:
Ronald Levy:

Except on my Grumman Tiger, you can change the brake pads without disconnecting the brake lines.  This is why the FAA took the view that something which is legal preventive maintenance on one plane might not be on another.  One has to examine the entire process to make the determination.

didn't say I had to disconnect the calipers (although I have under the A&P's supervision to rebuild them), I just said that removing it would be a no no without proper "supervision"


And I was saying that on some planes, there would be no need for a mechanic's supervision/signature to replace the pads since it isn't a "complex assembly operation", but on others where disconnecting hydraulic lines is involved, it could be, which is why there's no one-size-fits-all answer.