Return to service

Maintenance is an area that’s totally foreign to most pilots, even those who own aircraft. Technicians have to deal with the same types of responsibility and regulations pilots do, however, so it’s good to know exactly what it is they do. Among those responsibilities is the authority to return an aircraft back to serviceable condition. It’s important to learn now what that means and what it doesn’t.

Part 43 of the federal aviation regulations specifies issues surrounding aircraft maintenance. Section 43.5 details returning an aircraft to service, and the first thing you’ll notice when you read it is that it says nothing about a qualified airframe and powerplant technician having to approve an aircraft for return to service. The reason is because aircraft owners and operators can do certain maintenance tasks on their own aircraft and make the necessary endorsements. Those tasks can be found in FAR 43 Appendix A. Section 43.5 is very basic. It boils down to three points–that the person returning to service must make a logbook entry, that the repair be made in accordance with a manner prescribed by the FAA, and that any change resulting in a performance or limitation change be noted appropriately in the flight manual.

Although simple in nature, the implications of the regulation are huge. Endorsements are the FAA’s equivalent of signing your name in blood. Flight instructors know this well. To put an endorsement in a logbook is to put your certificate on the line. It’s the same for flight instructors and mechanics. What that means for pilots is that in most cases, properly qualified maintenance technicians can be trusted to do their best to make the airplane safe and not return it to service before it’s ready. That’s evident in accident statistics where fewer than 20 percent of which are maintenance-related (that includes airborne failures of components that haven’t been previously worked on).

With that being said, mistakes do happen. There have been documented cases of accidents that occurred as a result of a maintenance flub. As a pilot, you can do some simple things to avoid such a situation.

1. Get to know your maintenance personnel

If your school doesn’t have a shop and you don’t already know these professionals, make the effort to go to the shop where work on your school aircraft is done. The benefits to having a personal connection with a maintenance tech are many. Most will let you look over their shoulder while they work, which means you’ll get some intimate knowledge not only of the type of work these folks do, but also the systems on your airplane. They can be a go-to source for systems questions, and you’ll less intimated in the future to casually ask them about an issue with your training airplane. Plus, maybe you’ll find your mechanic for your own future airplane in the process.

2. Read maintenance logbooks

Knowing who did what to the airplane is imperative. Many schools make this quite difficult because the maintenance logs are understandably locked away for safe keeping. But if an airplane’s been down–or even if it hasn’t–take the time to study the logs and ensure you know what has been done to it in the recent past.

3. Do thorough preflight checks

This point can’t be overstated. If you’ve ever wondered why we do a control check before takeoff, maintenance is one of the reasons. Many accidents have been caused by aircraft controls being hooked up backward after maintenance. This is especially true of the annual or 100-hour inspections, where these components are inspected. A control check is cheap and quick insurance against a senseless accident. There are many such examples of this. Carefully checking things such as oil, inspection plates, tires, and cockpit instruments could save you a heap of trouble.

Although some owners can fall into these traps, it’s much easier for them to keep track of maintenance records because they retain possession of the important documents. But students are no less immune to the issue. They just have to try harder to keep up with it.

Ever find a maintenance problem after the airplane has been returned to service or know someone who has? Tell us about it.

–Ian Twombly

  • Ben

    I was doing an engine run-up after a 100-hour check. I pulled the carb heat control in the cessna 152, and the wire pulled out…and out…and out…until I was holding a knob attached to about five feet of metal wire in my hand.

    Thus, the value of the runup was taught to me. We taxied back to the hangar and the AMT re-wired the carb heat in about five minutes, and we were good to go.

  • Adam

    very interesting read. I was just thinking about this subject on my way to work this morning. It stemmed from an article I did on my blog about career options in aviation. I’m wanting to get my PPL and one would like to own my own airplane. This is good information to know. Thank you for sharing.

  • Ron Amundson

    1. We had just finished a major rebuild… and everything looked good on the ground. Alas, the trim tabs cabled were reversed. Fortunately, both my boss and the mechanic were in the a/c, and the 2 of them had enough strength to prevent a stall, get the a/c under control, and then figure out the issue with the trim.

    2. One of our customers bought a new airplane, and had a pre-purchase inspection done at the owners field some 500 miles away. Upon arrival at home base, I could see whisps of smoke coming out of the cowling… it turns out a screw driver was left on the cylinder head during the prepurchase inspection.

    3. We had a new client come in one day for a annual, and the pilot said that the trim tab was sticky at times, but he could never get it to repeat for his prior mechanic. Apparently at some point in time, the horizontal stabilizer had been repaired, and a bucking bar was left inside. Being the bar had free range inside, sometimes it would interfere with the cables, and other times, it would bounce through the ribs, such that it couldnt be seen.

  • glen morthorpe

    You are totally wrong to let pilots believe they can repair airplanes with defects. FAR43 does say who can return an airplane to service and it is not a pilot, except for some preventive maintenance such as an oil change or tire inflation. A pilot can assist, of course, but only under supervision, and cannot write the logbook entry returning the airplane to service.
    Any time an entry is made of a defect that airplane is grounded until the entry is cleared, by repairing, replacing or defering. In general, only an A&P or IA can do this. Flying with an open squawk is illegal. This includes items such as nav lights or second radios, even though the pilot might not need them. If they are written in the log, the entry must be cleared prior to flight. Knowingly flying an airplane with a defect, even if it is not written up, is illegal. FAR 43.3 details who can return an aircraft to service, and App A details the limitations of what a pilot may do. Note that this does not include repairs, just for preventive maintenance.
    FAR 91.213 details flight with inoperative equipment and instruments, and states the methods under which this can be done. It does not permit a pilot to ignore the defective equipment nor does it allow a pilot to self-certify the airplane. In all cases at least an A&P is required to sign off the airplane as safe to fly, and the PIC/Owner must also be satisfied that it is safe.
    You can be sure that the insurance companies and the FAA are very aware of these rules, and we should be careful to give only accurate information to our students.

  • Ian Twombly


    I disagree. Show me where in the regulations it says an owner can’t work on his airplane and return it to service? There was no mention of pilots performing major repairs. And I never said pilots should fly with open squawks. What specifically is inaccurate about the post?


  • Jay W

    I speculate that Glen was reading the second paragraph, where you noted that there is “nothing about a qualified airframe and powerplant technician having to approve an aircraft for return to service” in FAR 43.5. That is correct, because different people are required to return the airplane to service under different circumstances.

    However, someone not reading that statement carefully may take it to imply that an A&P is NOT required to return the aircraft to service, which is a VERY different meaning! :)

  • http://AOL wrobertcarnes

    I together with the chief pilot were recently cited by the FAA for flying a twin training accft that had exceed the time on a oil additive AD. by one hour. Heretofor the time for the accft (Oil hrs. etc.) had been posted by the school operators maintenance crew which we regurly revied for compliance and safety. Should we, as instructors now have to review the logs of the accft every time we use the accft and not rely on the accuracy of the schools maintantence shop.?

  • http:[email protected] Patrick Winter

    I believe your correct Glen. Sorry Ian but read on 43.3.

  • glen morthorpe

    Your article was great, except for the second paragraph.
    [[Section 43.5 details returning an aircraft to service, and the first thing you’ll notice when you read it is that it says nothing about a qualified airframe and powerplant technician having to approve an aircraft for return to service.]] Yes it does, in 43.3, see below.
    [[ The reason is because aircraft owners and operators can do certain maintenance tasks on their own aircraft and make the necessary endorsements.]] Yes they can, but not repairs. They are limited to certain preventive maintenance tasks that do not include repair, replacement, or defering the work.
    [[ Those tasks can be found in FAR 43.17.]] No, 43.17 is purely for Canadians who work on US airplanes, it has nothing to do with US pilots.

    91.213 details what must be done when there are inoperative items of instruments and equipment. If anything is not working, the airplane is grounded. A pilot does not have the authority to fly an airplane with inoperative instruments or equipment (basically anything that was originally in the airplane or added later, including carpets, seat belts, radios, etc). Only a mechanic can release the airplane for flight, even if the pilot is totally happy to fly it he cannot do so without a sign-off from a mechanic.

    Suggesting otherwise is a risky thing to do and exposes you to liability.

    Except as provided in 43.3 no person may maintain an aircraft, airframe, engine, propeller, appliance or component part. 43.3 (b) says a mechanic can do this, or a person working under the supervision of a mechanic, but the mechanic must personally observe the work being done. This person cannot carry out any inspections (43.3.(d))

    43.5 says the work must be signed off, but 43.3 already says who can do this work, and who can carry out any inspections, and this does not include a pilot.

    43.7 tells you who is authorized to return an aircraft to service, or an airframe, engine, propeller, appliance or component part. 43.7 (b) says clearly this can only be a mechanic or IA.

    A pilot is authorized to do preventive maintenance, and to sign this out, but preventive maintenance is defined and does not include repairs or replacing parts, except under very limited restrictions. Look at Appendix A (c) for the details of who and what.

    So a pilot cannot carry out repairs.

    A pilot cannot sign out any repairs or return an aircraft to service after maintenance (or repair work) has been done.

    Your article was a good opportunity to teach the rules, maybe you could read up on the regulations, talk to a couple of experienced mechanics, and do it again. Teaching how to make a maintenance logbook entry would also be a great topic. Is it OK to fly with a busted radio, for example, if it is not written in the logbook?

  • Ian Twombly

    First and foremost, my bad on saying 43.17. I meant to cite the appendix and for some reason got off the topic there. Will make that change.

    Glen, I’ve read and reread your comments, and I fail to see what’s specifically wrong about the post (other than the reg number). I never said a pilot can repair an airplane. I said they can return it to service after certain maintenance tasks. The way I read 43.5 it says exactly that. And 43.3 backs that up, as you pointed out. As far as flying with inop equipment, there’s no mention of that in the post. So how is it risky to say, “The reason is because aircraft owners and operators can do certain maintenance tasks on their own aircraft and make the necessary endorsements?” Preventative maintenance is a type of maintenance.

    Thanks for the discussion.


  • glen morthorpe

    You are talking semantics. I am sure you know the difference, but too many pilots out there do not. They are not going to pull out a copy of the regulations and read about preventive maintenance, and even if they do, it is written so poorly they probably won’t understand it. What they will remember is your post saying that the FAA does not restrict who can repair and sign out an airplane, a statement that is true only under a very limited set of circumstances, and can get them into real trouble, legally and especially in the air.
    Even an A&P is restricted in what she can do, depending on her qualifications, so a pilot “fixing” an airplane then signing it out will not be legal at all.
    We should be encouraging pilots to follow the regulations, not interpret them.

  • andrew h.

    Glen wrote {You are totally wrong to let pilots believe they can repair airplanes with defects.} In fairness, Ian didn’t say this. Nor was it implied, except with reference to things the FARs alllow an owner/pilot to do. And, oh by the way, it must be the OWNER pilot who does the ‘preventive maintenance (PM), if not an IA/AP. Can’t be just any ‘operator.’ Ian actually says this, and I am giving it emphasis here.

    The list of PM actions is actually quite long, and deserves study by any owner inclined to get greasy. I’m one of those. From years of owning cars and working on them, as much for any other reason to know what EXACTLY was done and how well. Same with my bird. So…if I take ‘er down for PM, say for a tire change and bearing lube, I want that noted in the log. Thus, SOMEONE must return her to service. FAR allows me to do it …if it’s a maintenance action I’M PERMITTED TO DO. Thing is, as Glen says, semantics bears watching. I would call a tire change a repair. Not a major repair, but a repair. In the form of a PM action. I can sign that off.

    Glen said (FAR43 does say who can return an airplane to service and it is not a pilot, except for some preventive maintenance such as an oil change or tire inflation. ) C’mon, Glen. Be fair. You’re gonna scare a bunch of folks into not getting involved with their airchines. The list is much longer and more involved than airing tires and an oil change.

    Glen said “They are not going to pull out a copy of the regulations and read about preventive maintenance, and even if they do, it is written so poorly they probably won’t understand it.” Have to admit it’s not 100% clear, especially when it starts going on about ‘except those things expressly permitted’ and other double negatives, etc, etc. BUT, Glen, you’re wrong about pilots not pulling out the FAR and concentrating on what, exactly, he or she can do personally. I did, and most of the pilots I hang with are VERY familiar with the PM provisions. And, this is all Ian was trying to illuminate, I think.

    As Ian says, PM is a kind of maintenance. And in my book, it’s splitting hairs to say it’s not a ‘repair.’ But, if someone wants to look at it that way, I suppose that’s ok too.

    Great thread.

  • Ian Twombly


    Thanks for jumping in. Good catch on the owner/operator thing. I rechecked Appendix A, and you are correct. It says owner very clearly. Then I rechecked 43.3 and it says owner or operator. Now I’m confused…

    I was always taught owner/operator can do preventative maintenance, but honestly I was surprised the FARs would allow just an operator to do this. Seems like the FARs conflict as well.

    Please advise if I’m reading incorrectly.


  • andrew h.

    Ian, I believe you are correct, and you have thusly changed my understanding of this issue. As clearly as it states anything, 43.7(f), which talks about WHO can ‘Return to Service’, refers us to 43.3(g) which clearly says ‘aircraft owned OR operated by that pilot’ can receive PM. Pretty clear. After reading and referring about a dozen times to be sure.

    Personally, I think it’s appropriate the FAA identifies owners as an echelon of maintainers. I like that. I also think it’s very reasonable. Add to that, as an INVOLVED owner, I have caught omissions, some quite serious, that IAs have not cleaned up after work was signed off. No one is perfect, right?

    But…back to the original thread that you began. Owners (and it seems ‘operators’ as well) can ‘return to service’ an aircraft that they have performed PM upon. Was an aircraft ‘Removed from Service?’ If it wasn’t, then it does not require a ‘Return.’ I only know this, Ian. If I take my wheels and tires off, that baby is ‘Removed from Service’ while in that state. Is this a fine point. I do not know. At this point, the thread you originated has produced the intended result. We’re a little bit smarter, and, thus, safer. Have a good ‘un.

  • George K

    Does that mean if I find a locknut on a stab strut wire for instance not tight can I tighten it. to me thea is preventive Maintenace.
    Right or wrong??