The Savvy Aviator #61: Secrets of Cost-Effective Maintenance


Under the FARs, performing maintenance is the job of an A&P mechanic or FAA-approved repair station, but managing maintenance is the owner’s job. In essence, the FAA looks at each aircraft owner as the Director of Maintenance (DoM) of a one-aircraft aviation department. Unfortunately, few owners know how to do this important job, and most do it very poorly. Many owners leave it to their A&Ps to manage their maintenance, and generally are unhappy with the results.For the past four and a half years, I’ve been going around the country teaching owners how to manage the maintenance of their aircraft properly. My seminar is a very intense weekend of training — at least 17 hours worth — that covers a wide variety of subjects ranging from reliability-centered maintenance to regulations to engine condition monitoring to troubleshooting (just to name a few of the topics covered).But to make a long story short, the basic principles of good maintenance management can be boiled down to five simple principles. Follow these five principles religiously and you’ll discover that you have a safer and more reliable aircraft while at the same time spending a great deal less on maintenance.

Rule 1: Choose The Right Shop

To use a building-trades analogy, an aircraft owner’s job is to act as the “general contractor” for his aircraft maintenance. The owner hires skilled tradesmen — maintenance shops, mechanics and other technicians — to do the necessary maintenance work, then manages them to ensure they perform as desired and that they come in within schedule and budget, and occasionally fires them if they don’t perform to expectations.As in the building trades, the owner’s most important task by far is the first one: hiring the right shop, mechanic or technician for the job. If you hire the right person for the job, the rest tends to work out well most of the time. Conversely, if you hire the wrong person for the job, the best management skills in the world may not be sufficient to rescue the situation.Most owners do a miserable job of choosing shops and mechanics. Often, they simply use the shop at their home base because it’s convenient to do so. Or they choose a mechanic because he seems friendly. Or one that some aircraft-owner friend has nice things to say about.Doing the job right requires much more “due diligence” than that. You need to interview a prospective shop or mechanic just as you would a prospective employee. What do you look for in such an interview? Lots of things, but the most important attributes you should look for are what I call “the three C’s.” The mechanic (or the shop’s DoM) must be competent, communicative, and cooperative.Competent means that the mechanic or DoM has as much experience as possible with your particular make and model of aircraft. Over the years, I’ve found that a mechanic’s “total time” is far less important than his “time in type” — that is, his experience with your particular make and model. Just because a mechanic has done a great job on your friend’s Bonanza, Saratoga, Ovation or SR22 doesn’t mean that he’s competent to work on your Cessna T210 or 340A. Before you hire a mechanic, grill him about his experience with your particular make and model, and insist on getting specifics about his experience, not generalities. You want to find the mechanic or shop with the most “time in type” you can.Communicative means that the mechanic or DoM is committed to keeping you “in the loop” while your aircraft is in the shop: keeping you continually apprised of status and consulting you whenever a decision needs to be made. Many mechanics are excellent at this, but many others are not; their attitude is often, “You hired me because I’m an expert at what I do, so please go away, leave me alone, and let me do my job.” If a mechanic has this attitude, you need to find that out before you hire him — and then run, don’t walk, in the other direction.Cooperative means that the mechanic or DoM is someone that you find easy to talk to, and who is willing to listen to your directions and desires and do things your way to the extent that he can (while still complying with applicable FARs). It means someone you “can do business with.” Once again, many mechanics are cooperative and customer-oriented, while others are rigid and dogmatic — they believe that there are only two ways to do something: their way and the wrong way. Dogmatic mechanics tend to view the world in black and white, while cooperative ones view it as it actually is: a thousand shades of gray. Seek out the cooperative, customer-oriented ones — avoid the dogmatic ones like the plague.

Rule 2: Insist On A Written Estimate

Once you perform your due diligence and hire the right shop or technician to work on your airplane, your next job is to ensure that the shop doesn’t wind up presenting you with an invoice that will make you faint or take out a second mortgage. How do you accomplish that? Simple: Always make sure you know what maintenance is going to cost before you approve it.You might think this is so obvious that it’s not worth saying. You’d be wrong. It always astonishes me how often owners approve maintenance without knowing what it’s going to cost, and then suffer from serious “sticker shock” when they get the shop’s invoice. It also astonishes me how often shops undertake expensive work without obtaining the owner’s explicit and informed approval.The irony is that this couldn’t happen if it were your automobile that was in the shop for maintenance rather than your airplane. Virtually every state has laws and regulations that require automotive maintenance shops to present each client with a detailed work order and cost estimate, and to obtain the client’s explicit approval (usually in writing) before starting work. Those same laws and regulations usually prohibit the shops from exceeding the agreed-to estimate without going back to the client and obtaining approval of an amended estimate.There are no such laws and regulations for aircraft-maintenance facilities. Aircraft owners are generally assumed to be sophisticated folks who are smart enough to find out what the work is going to cost and get it in writing before giving approval to proceed. Bad assumption! It’s astonishing to me how often aircraft owners fail to ask the threshold question, “What’s that going to cost?” before approving work, and only find out the answer at invoice time (when it’s too late to affect the outcome).Ah, but what about an annual inspection, where the shop doesn’t know what things will cost until they open up the aircraft and inspect it? That’s easy, too. Owners must insist that an annual inspection be divided up into three distinct, sequential phases: inspection, approval, and repair.During the first phase (which is typically covered by the shop’s flat-rate inspection fee), the shop opens the aircraft, inspects both the physical aircraft and the maintenance records, and generates a report listing the discrepancies found. That discrepancy list should clearly identify “airworthiness items” from other, lesser discrepancies. It should also include a specific repair recommendation for each discrepancy, and a specific cost estimate for parts, labor, and outside work.During the second phase, the owner reviews the discrepancy list, recommendations and estimates. He asks questions about anything he doesn’t fully understand to ensure “informed consent.” He may want to get a second opinion on some items from another mechanic or his type-club tech rep. He may want to explore various alternatives to the repair recommendations offered by the shop. At the conclusion of this phase, the owner goes back to the shop with specific direction (preferably in writing) as to which items on the list he wants repaired, and how he wants the repairs to be done.During the third phase, the shop performs the repairs as directed, and the owner fully expects that the invoice will conform fairly closely with the written estimates that he has approved. Should unforeseen contingencies arise while doing the work (as they sometimes do), the shop must stop work, go back to the owner with an amended estimate, and obtain the owners explicit authorization to proceed (or not).As obvious as this may seem, it’s frightening how often it doesn’t occur. Many shops engage in a practice that I call, “Inspect a little, fix a little, inspect a little, fix a little, lather, rinse, repeat.” If a shop does that, then there’s no clear “decision point” at which the owner can review the discrepancy list and cost estimates, achieve informed consent, and give explicit authorization to proceed. Owners must insist that shops not operate in this fashion, and fire them if they won’t cooperate.

Rule 3: If It Ain’t Broke, Don’t Let ‘Em Fix It

Every aircraft service manual contains page after page of recommendations for scheduled preventive maintenance. Do this every 50 hours. Do that every 100. Do something else once a year. The lists of scheduled tasks go on and on. The service manual for my Cessna 310 has no less than 350 separate, scheduled, maintenance tasks.Any owner who follows the manufacturer’s scheduled maintenance recommendations is simply throwing money down the drain. Why? Simply because the very notion of a one-size-fits-all maintenance schedule makes no sense from a scientific or engineering point of view. It makes absolutely no sense to apply the same maintenance schedule to an aircraft based in Tampa and one based in Tucson. Or one that flies 30 hours a year and another that flies 300. Or one that’s tied down outdoors and another that lives in a heated hangar. Yet that’s what the service-manual recommendations call for.Consider this: My Cessna 310 service manual calls for removing, disassembling, cleaning, lubricating, reassembling and reinstalling the elevator, rudder, and aileron trim-tab actuators every 200 hours. The service manual for virtually every Cessna single and twin model has a similar recommendation. This involves at least six to eight hours of work. So if you actually “did it by the book,” you’d add roughly $3 per hour to the cost of flying.In the 21 years and more than 3,000 hours that I’ve owned my Cessna 310, I’ve never disassembled or lubricated any of the three trim tab actuators. Not once! Why? Simply because they didn’t need it — and last time I looked, you don’t get extra credit for doing unnecessary maintenance.How do I know the trim tab actuators didn’t need to be lubricated? Because I check their condition at least annually, and it takes all of two minutes to do so. The procedure is dead simple, and involves two steps. First step is to climb into the cockpit and rotate the trim wheel all the way from one end of its range to the other, checking to see whether the trim wheel rotates smoothly without any sign of resistance or binding. Second step is to climb out of the cockpit, walk over to the trim tab, measure how much free-play it has, and check that against the maximum allowable free-play set forth in the service manual. If the trim wheel moves smoothly through its full range, and if the trim tab does not have excessive free-play, then the trim tab actuator is just fine and doesn’t need to be fooled with.OK, so if a Cessna trim-tab actuator can go for 21 years and 3,000+ hours without needing to be lubricated, why does Cessna say to do it every 200 hours? Because Cessna’s service-manual recommendations have to work for every airplane in the fleet, even the worst-case airplane. And there’s probably some Cessna somewhere — probably a Cessna 185 on floats up in Alaska that spends six months of the year operating off salt water and the other six months of the year locked up in a hangar because the weather is too bad to fly — that actually does need to have its trim tab actuators lubricated every 200 hours!But my airplane lives in a hangar and flies regularly throughout the year, so servicing the trim-tab actuators on my airplane every 200 hours would be gross overkill (by a factor of 10 or 20).More to the point, it never makes sense to maintain a component on a fixed timetable (i.e., every so many hours or so many months) when it’s feasible to monitor the condition of the component (which takes two minutes for trim-tab actuators) and maintain it only when the condition monitoring tests indicate that maintenance is actually required. We call this “condition-directed maintenance” (CDM) as opposed to “time-directed maintenance” (TDM).CDM is always more efficient than TDM, because it causes components to be maintained only when they actually need maintenance, instead of when the manufacturer guesses it might need maintenance … especially when the manufacturer’s guesses are heavily laced with pessimism to account for the worst-case airplane in the fleet.We should only perform TDM when CDM is infeasible because no practical condition-monitoring technique exists. Studies show that CDM is feasible for well over 90 percent of the components in our aircraft.Many shops and mechanics insist on “Doing everything by the book,” and often suggest to owners that this is required by regulation. In fact, manufacturer-recommended maintenance schedules are almost never required by regulation, and almost always represent a huge waste of money. If your shop is one of those “Do it by the book” facilities, just say, “No.” And if they won’t take “No” for an answer, find another shop.

Rule 4: Don’t Fix It Until You’re Sure What’s Wrong

How many of you have had the experience of putting your aircraft in the shop to get some squawk fixed, then getting it back from the shop with an invoice, only to find on the first flight after maintenance that the squawk wasn’t fixed? Hmmm … I see a lot of hands raised, and I see a bunch of you with both hands raised. Seriously, I doubt there’s an aircraft owner who hasn’t had this experience, and most have had it multiple times.Anytime this happens, you’ve experienced a troubleshooting failure. The shop wasn’t lying on the invoice when it claimed to have spent H hours working on the problem, and D dollars in replacement parts. The problem is that the H hours of labor and the D dollars in parts didn’t fix the problem. Therefore, clearly the H hours were spent working on the wrong thing, and the D dollars were spent replacing parts that didn’t actually need to be replaced. Why? Because the shop tried to fix the problem without first thoroughly understanding its cause. That’s a troubleshooting failure!Inadequate troubleshooting is probably the single biggest cause of wasted maintenance dollars. Why does it happen? There are a number of reasons. One is that many aircraft problems occur only in flight and cannot be reproduced in the maintenance hangar — and if a mechanic can’t reproduce the problem, then there’s no way for him to troubleshoot it systematically, and he’s forced to resort to guesswork about the cause of the problem (and those guesses are often wrong). Another is that good troubleshooting requires excellent systems knowledge, and sometimes our mechanics don’t know some of the systems on our aircraft as well as they should (which is usually our fault for picking the wrong mechanic for the job).In my weekend seminars, I spend fully half a day — one quarter of the weekend — on the subject of troubleshooting. That discussion is far beyond the scope of this article. But the bottom line is this: Never let a mechanic try to fix something unless and until you’re quite sure that he has diagnosed the problem thoroughly and understands exactly what’s causing it. Try never to put a mechanic in the position where he has to guess what’s wrong. When mechanics guess, owners pay.

Rule 5: Don’t Overkill The Problem

Finally, when your airplane has a problem and you’ve diagnosed it properly, get it fixed but don’t go overboard. I can’t tell you how many times I’ve seen airplanes go into annual with one or two weak cylinders and come out with a top overhaul (six new jugs costing $10,000 parts and labor). That’s nuts. If you have one or two weak cylinders, have them repaired — or replaced if they turn out to be unrepairable — but for Pete’s sake, leave the rest of the cylinders alone.Just today, I was corresponding with a T210 owner who explained to me that at his 2007 annual inspection, the compression test revealed one cylinder that measured 50/80, so the mechanic replaced the cylinder with a new one (at a cost of $1,800). Then at the 2008 annual, another cylinder came up 50/80, and the owner decided to “major” the engine (at a cost of $35,000).Give me a break! We don’t overhaul engines because of weak cylinders. We repair the cylinders (typical cost $300 to repair plus $600 to R&R) or, if they’re unrepairable, we replace them (typical cost $1,200 for a new jug plus $600 to R&R). We only overhaul an engine when something goes wrong with the “bottom end” that can only be repaired by splitting the case: a spalled cam, a cracked case, a prop strike, or something like that.

This Stuff Really Works!

That’s all there is to it:

  • Chose the right shop — one that’s competent, communicative, and cooperative.
  • Insist on a written discrepancy list and estimate before approving any work.
  • If it ain’t broke, don’t let them fix it.
  • Don’t let them fix it until you’re sure what’s wrong.
  • Don’t overkill the problem.

These five simple rules encapsulate the essence of good maintenance management. Follow them and you’ll wind up with a safe, reliable airplane while saving many thousands of dollars a year in unnecessary maintenance costs.These principles have worked beautifully for me for decades and thousands of hours. Now that I’ve started a company (SAMM) that provides professional maintenance management, these principles are working every day for the numerous owner-flown aircraft under our management and saving our aircraft-owner clients thousands of dollars a year. I guarantee they’ll work just as well for you if you let them.

Mike Busch is the founding editor of AVweb. He now operates Savvy Aircraft Maintenance Management at

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