Maintenance Regulations—There Aren’t Many

I had a chance to meet Mike Busch, the Savvy Aviator, a couple of weeks ago when people who write for Sport Aviation magazine got together to chat in Oshkosh. I really loved talking to Mike because he and I have written a lot about how badly most piston airplane owners misunderstand the FAA regulations governing maintenance of their airplanes. There just aren’t a lot of rules.

FAR Part 43 is the chapter of the FAA’s rulebook that governs maintenance, rebuilding, and overhaul for all types of aircraft. And it’s the shortest chapter in the entire rulebook – just 17 rules. In contrast, FAR 45, the section governing identification and registration markings of aircraft, has 33 rules. FAR 47, the chapter on how to register an aircraft, contains 71 rules. And FAR chapter 91, the general operating rules, contains hundreds of individual rules.

In fairness, I must note that FAR 43 does have several rather long appendixes that are somewhat specific. Appendix A is important to airplane owners because it lists the preventative maintenance tasks an airplane owner can perform. On the list are things like changing landing gear tires or landing light bulbs, installing new aircraft batteries, and similar routine maintenance.

Overall, for piston-powered airplanes weighing less than 12,500 pounds for takeoff, FAR Part 43 does not include much specific detail about what is required to legally maintain the airplane. It’s a different story for turbine-powered airplanes, or those in the transport category weighing more than 12,500 pounds. For those airplanes very specific and detailed maintenance programs are required. Manufacturers create maintenance plans an owner and his shop can use, or an airplane owner can devise his own maintenance plan and seek approval from the local FAA inspectors.

The basic maintenance requirement for a piston airplane with a standard-category airworthiness certificate is that it undergo an annual inspection. The other maintenance specification that is very clear deals with the transponder and altimeter check every two years. The only other very specific maintenance requirements come from airworthiness directives that can demand inspection, overhaul, modification, or even replacement of any component of the airplane.

Aircraft owners benefit in many ways by participating in owner-assisted annual inspections. These owners are learning about electrical systems at an EAA SportAir Workshop in Canada.

What you can’t find in FAR 43 or its appendixes is any mention of TBO. Piston engine makers and the airframe manufacturers who install the engines issue a time between overhaul recommendation, but it has no FAA regulatory force for those of us not flying our airplanes for hire. TBO is a recommendation that you should start thinking about engine overhaul or replacement after the recommended number of flying hours or calendar time has passed, but no special action is required.

Appendix D of FAR 43 lists items that must be checked on an airplane during an annual or 100-hour inspection, but the wording is so vague that it doesn’t provide any real specificity on what passes inspection, and what doesn’t. For example, Appendix D does require a compression check of the engine cylinders. But if the compression is “weak” – which is the word the FAA uses – the inspector is supposed to check for “improper internal condition, or improper tolerances” inside the cylinder. But what is “weak” compression? The FAA doesn’t say. What is an improper “internal tolerance” in a cylinder? That’s up to the inspector, too.

Appendix D repeatedly uses the words “poor condition” to be checked for. What the heck is “poor condition”? Under the rules, “poor condition” is what the mechanic with an inspection authorization (IA) looking at your airplane says it is. Is “poor condition” un-airworthy? I guess it is, because it’s the main thing on the list of Appendix D that an inspector is supposed to look for.

The lack of maintenance regulation leaves mechanics, inspectors, and airplane owners all with a lack of guidance, and with risk. The mechanic and inspector minimize their risk of being blamed for something failing if they replace or overhaul as many parts of the airplane as possible at each inspection. The airplane owner is at risk for spending a huge amount of money that isn’t necessary to keep the airplane reliably airworthy.

Mike Busch, creator of the Savvy Aviator seminars. His column appears monthly in the pages of EAA Sport Aviation.

I am not saying, nor do I believe, that APs and IAs are dishonest or intentionally run up annual inspection and other maintenance bills. The FAA has simply put them in an almost impossible situation of using their own judgment to determine how much wear is too much. Aircraft and engine manufacturers do create inspections guides with some specific detail on what passes inspection and what fails, but the manufacturers are also in a CYA position. If their inspection guide directs the mechanics to replace or overhaul a component with even minimal wear, they have helped establish an “I warned the owner about that” record that can be used as defense in court if something goes wrong.

The system unintentionally conspires to drive up maintenance costs with no real discernable benefit in flying safety. That’s why Mike Busch has been so successful with his Savvy Aviator seminars that teach pilots about the maintenance rules and how to effectively get the maintenance they need from their shop without paying for unnecessary work.

The best summary of the problem I ever heard was from an experienced IA who said, “I try to tell my young A&Ps that an annual is an inspection and repair only as necessary; it’s not an aircraft restoration.” I wish all shops would follow that direction.

You can become savvy with your aircraft maintenance by watching a Mike Busch webinar every month at 8 p.m. CDT as part of EAA’s webinar series.


This entry was posted in Aircraft, Industry & Government, Mac Clellan's Left Seat Blog, Safety, Technology. Bookmark the permalink.

13 Responses to Maintenance Regulations—There Aren’t Many

  1. Frank Gregory III says:

    My understanding of the article is that Mr. Busch has made a lot of money or a living off his seminars while blasting the average A&P mechanic trying to make enough money to stay of welfare.

    • Frank, that’s sheer nonsense.

      I have neither made any significant amount of money doing my seminars (for which I charged just enough to break even), nor blasted A&Ps for making money. Quite to the contrary, I want A&Ps to make money. They’re seriously underpaid. It makes no sense for an aircraft mechanic to make less than an automobile mechanic, but that’s exactly the current situation. I know a lot of A&Ps, and I don’t think one of them wants his kids to go into the same profession. That’s a serious problem, and doesn’t bode well for the future of the GA maintenance infrastructure. We desperately need good, experienced, talented GA mechanics to stay in business, and we need others to take their place when they retire.

      My firm Savvy Aircraft Maintenance Management works daily with hundreds of maintenance facilities throughout the US (and a handful overseas) and has an absolutely excellent working relationship with the vast majority of them. All our Savvy account managers are current or former shop owners or directors of maintenance with at least 20 years experience in GA maintenance. These guys know how the world works on the shop floor of a GA maintenance operation because they’ve all been there and done that. We work hard to protect the shops we work with, and to make sure they are treated fairly and get paid promptly.

      The only A&Ps I criticize are ones that don’t understand the concept of good customer service, particularly ones that try to intimidate aircraft owners into doing work that isn’t necessary, isn’t required by regulation, and doesn’t provide any demonstrable benefit to safety and dispatch reliability. There are still some out there, and they need to be avoided like the plague.

      In my experience, there are plenty of excellent GA maintenance shops and mechanics out there, so there’s no reason any aircraft owner should ever have to put up with the less-than-excellent ones. My goal in my owner seminars and my firm’s managed maintenance program has always been to teach owners how to tell the difference between good maintenance and bad maintenance, and hopefully to vote with their feet and credit cards. I think we work with more GA maintenance shops than any other firm in GA, so we have a unique perspective on which shops are the best ones, which are the worst, and which are somewhere in between. We do our best to steer our clients toward the excellent shops and away from the not-so-good ones. If there’s any justice in the world, the excellent shops should prosper and the not-so-good ones should fail. I believe that’s the way the free enterprise system is supposed to work.

  2. David Camp says:

    Good stuff! There would be a lot more flying and customer cash flow if owners could be assured the costs would be reasonably minimal – and only increase if they felt better about it. The anxiety of feeling like you’re going to get ‘taken’ (or in-fact do) actually drives many enthusiasts from the sport. I know some A&Ps that still make good money and have all the work they can handle, because their customers know they do their best to keep costs down. In-turn, their customers spend more with them because they are comfortable with handing the A&P their wallets. It’ simple business. Raise the average invoice and lose customers. Smart business is good for everyone.

  3. Gary Brossett, A&P-IA says:

    Actually there are only a bakers dozen and one of them (43.17) is for our northern friends. There is no lack of guidance in 14 CFR 43…how about 43.13:

    shall use the methods, techniques, and practices prescribed in the current manufacturer’s maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, and practices acceptable to the Administrator,

    shall use the tools, equipment, and test apparatus necessary to assure completion of the work in accordance with accepted industry practices. If special equipment or test apparatus is recommended by the manufacturer involved, he must use that equipment or apparatus or its equivalent acceptable to the Administrator.

    shall do that work in such a manner and use materials of such a quality, that the condition of the aircraft, airframe, aircraft engine, propeller, or appliance worked on will be at least equal to its original or properly altered condition (with regard to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness).

    That’s volumes of guidance!!!

    • The late, great Bill O’Brien — longtime FAA national resource specialist for maintenance — was fond of saying in his IA renewal seminars that Part 43 is as short as it is (only 13 rules) because it was written for mechanics, and mechanics have a short attention span. (Bill was the only person who could stand up in front of 500 IAs and get away with saying something like that.)

      I’ve spent a lot of time parsing the maintenance regs and discussing them with FAA laywers like Ed Averman in the regulations branch at FAA HQ. In my opinion, those regulations are extremely well thought out and quite elegant in their simplicity and consistency. They give mechanics precisely the correct amount of guidance without being unnecessarily overreaching or restrictive. This is one area where I think the FAA got it right.

  4. Tony T says:

    So! As I read appendex A it appears that as an aircraft owner with a Private Certificate I can perform the following “Preventive Maintenance” task…. am I reading it correctly??

    (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.

  5. Mac says:

    Hi Tony,

    Yes, you are reading the preventative maintenance appendix correctly. Each of those items can be performed by an airplane owner or operator who has at least a private license. It gets a little complicated in the part about “does not involve complex assembly operations.” An example may be an airplane that requires the propeller to be removed in order to remove all of the cowling. Removing and replacing a propeller is not on the list, but cowling removal is. In that case the propeller removal would not be allowed, so neither could you remove the cowling on that particular airplane.

    Another question that often comes up is working around the main gear wheel brakes. You are allowed to replace tires, grease wheel bearings and swap wheels for skis. Each of those procedures on nearly every airplane requires removing parts of the brakes, and brakes are not on the list of things you can do. But is removing enough of the brake system to get a wheel on and off complex? I don’t think so, but that’s just another one of the judgment calls the rules leave to us.


    Mac Mc

  6. Bruce Thompson says:

    I’m glad I read your entire article because it finished at a different place than I thought it was going. I would like to comment on one of the comments that said the FAA couldn’t possible micromanage maintenance. They ABSOLUTELY can and are. If you don’t believe this go work in any FBO as an A&P. Especially one that has a repair certificate. You cannot believe the pressure and the impossible situations the feds put these shops and mechanics in. To further the problem, each FISDO operates as it’s own little fiefdom. What is approved in one FISDO is not approved in another. You have to use approved data but the manufacturers data is not approved. I could go on an on hopefully you get the idea. GA is in a real mess today and only partly because of the economy.Part of the reason most “shops” will install new parts, (mags, plugs, carbs) instead of rebuilding the old ones is liability and fear of the Feds violating them for some illogical reason. One problem we are working on currently concerns a radio that can be an MMEL item.The feds say if we remove it because it is inop, we must have a field approval or 337 or the airplane is grounded. It can fly all day long with the radio not working but if we remove it for repair the plane cannot fly!
    So yes the FAA can and does micromanage maintenance and it is strangling GA.

  7. Mac says:

    Hi Bruce,

    Your comments are on target, but also prove the point that there are few regulations, but tons of local opinion. A&Ps and IAs are stuck with whatever opinion the local inspector hands out because there are not specific rules that could be used on a national scale. The poor airplane owner as well as the A&P are stuck in the middle with every FAA office making its own decisions which do not apply a few miles away in the area of another FAA office.

    As for MMEL (master minimum equipment list, that doesn’t apply to most light airplanes. But if you fly on some sort of certificate such as FAR 135 for charter, you will almost certanly need an MMEL. For the owner of a typical light airplane the situation is even less clear because everything in the airplane must work as intended, or you must have plans to get it repaired and placard the item as not working. Of course, if you don’t use the item–like my old ADF before it was removed–who knows if it works or not? Worked the last time I turned it on.


    Mac Mc

  8. Kent says:

    I had one AMI say to me “THIS AIRPLANE CAN’T BE ANNUALED, IT HAS TO BE RESTORED”. Can you guess what I thought of that statement and the mouth it came from. If an AMI tells me something that I know he has no FAR or CAR to back him up I politely as him to give me a reference to the FAR/CAR. If he can’t the I do not comply with his “opinion”. A&Ps and IAs get raked over the coals by incompetent AMIs but only if we are “faint of hart”. CARs, yep they are still in force, except where it, or a part of one, is specifically superceeded by an FAR.
    I think this is mostly correct, what do you think?

  9. Mac says:

    Hi Kent,

    You are correct. CARs (civil air regulations) are still valid unless they have been superceeded specifically by an FAR (federal air regulation). Even that statement is not complete because FARs do not always replace a CARs. For example, a number of airplanes in production are being built to the CAR 3 standards that were in place when the airplane was first certified for production. Even though FAR 23–the rules that govern certification of new production small airplanes–have a number of differences with CAR 3, the airplane already in production under CAR 3 continues to abide by those rules.

    An AD can, however, trump either CAR 3 or FAR 23 and require any type of maintenance action, modification, regular inspection, airworthy life limit, or even replacement of an aircraft component, structure, accessory or whatever the FAA determines is necessary to make the airplane airworthy.

    Mac Mc

  10. Angus Mc says:

    Loved this article, but their is an implication: PILOTs need to understand their aircraft better and not rely on the AIs and A&Ps as providers of maintenance canon. No amount of maintenance or inspection relieves the pilot of the responsibility for determining if an aircraft is capable of safe flight. That implies, as Mac and Mike point out, a lot more latitude, but also more responsibility in maintaining their craft. Of course there is no substitute for a good relationship with a skilled A&P, and sure, many aircraft owners have enough disposable income to be able to foist maintenance issues off onto a qualified shop, but that isn’t a substitute for a solid understanding of what it takes to keep a plane airworthy.
    That’s the other half of the story: pilots-owners should really have a better understanding of the maintenance requirements and process for their aircraft and its systems. ’nuff said.

  11. Angus, I agree 100%. The job of being a competent aircraft owner is one of the toughest in aviation, yet for the most part owners receive no training, testing, or certification in how to perform that difficult job. Instead, they are left to learn the art and science of aircraft ownership through the school of hard knocks. There are some wonderful shops and mechanics out there to help owners discharge their responsibilities properly (and some not-so-wonderful ones as well), but at the end of the day the buck stops with the aircraft owner. –Mike

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>