The Savvy Aviator #20: The Most Dangerous Thing In Aviation?

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Aircraft owners are increasingly involved in the maintenance of their aircraft these days, and many participate hands-on. Is such owner-performed maintenance safe, or should maintenance be left strictly to the pros?

The Savvy Aviator

There's an old joke among aircraft mechanics that "the most dangerous thing in aviation is an aircraft owner with a screwdriver." (Or a wrench, or a toolbox, or a Swiss army knife ...)

For many mechanics, this is no laughing matter. I've been writing for many years (on these pages and elsewhere) advocating owner involvement and participation in maintenance, and I've gotten a fair amount of angry mail from repair station owners and working A&Ps who think I'm doing aviation a great disservice through this advocacy, and feel strongly that aircraft maintenance should be left strictly to the pros (like them).

It's not hard to understand where this idea originates. I doubt there exists a working general-aviation mechanic anywhere who doesn't have a few dozen horror stories about owner-performed maintenance nightmares he's found while working on GA aircraft: automotive hoses used in fuel systems; exhaust leaks patched with fiberglass and epoxy; rat's-nest wiring full of Home Depot plastic-insulated doorbell wire, Scotch electrical tape, Pep Boys' automotive crimp connectors and cold solder joints ... well, you get the idea. I'm the first to admit that I, too, have seen stuff like this in airplanes that really made me shudder.

(But then again, I've also seen plenty of things done by allegedly professional A&P mechanics that made me shudder. Unfortunately, the fact that someone holds an FAA certificate -- whether it be a pilot certificate or a mechanic certificate -- is no guarantee that he isn't a jerk.)

Some of the best-maintained aircraft I've ever seen are ones maintained largely by their non-A&P-rated owners. After all, no one is more motivated to do a first-class job of maintenance than the person whose posterior and those of his family are on the line.

Some of the most mechanically magnificent GA aircraft I've ever seen are kitplanes entirely built and maintained by their owners. If you exclude the initial test-flight period, these owner-maintained aircraft do not experience any greater rate of mechanical problems than do comparable certificated light planes. In fact, I suspect the average homebuilt is a damn sight better maintained than the average "professionally maintained" spam can.

So Who's Right?

Let's face it: There are plenty of aircraft owners who have the knowledge, skill and desire to work on their own aircraft and do a first-class job. On the other hand, there are also lots of aircraft owners who have little or no mechanical aptitude or inclination. Most readily admit that they are mechanically challenged individuals (a.k.a., "all thumbs") and happily leave the wrench swinging to the pros at their maintenance shop.

Then there are a small minority of owners who tinker with their aircraft even though they don't know which end of the screwdriver to hold, and wind up doing things that are illegal and unsafe. These are the folks that A&P jokes and horror stories are made of, but in truth they represent only a tiny minority of owners.

You Won't Save Money

There are lots of reasons to consider getting involved in swinging wrenches on your own aircraft, but generally saving money isn't one of them. While the labor rates at maintenance shops aren't exactly cheap, the fact is that you'd probably take an hour to accomplish what a professional A&P can do in 20 minutes. At least that was my experience when I started swinging wrenches on my airplane more than 15 years ago, and that of several aircraft-owner friends who do their own maintenance. Even though I now have a lot more experience and hold an A&P/IA, I'm still a lot slower than a career mechanic who swings wrenches every day. As owner-mechanics, we consider ourselves safe, competent and careful ... but slow.

Think about it. A working A&P can hang a cylinder on an engine in 20 minutes or so. No big deal: Install the base o-ring, pre-oil the barrel, insert the piston into the barrel using a ring compressor, lift the jug into position, slide the wrist pin through the piston and con rod, push the jug over the studs, thread on the hold-down nuts, and then torque them into place.

But when I hang a jug, I spend 20 minutes watching the TCM video just to make sure I remember all the necessary steps (since I haven't hung a jug since three years ago), and another 10 minutes looking up the torque values and torque sequence (stuff any working A&P knows from memory because he changes jugs every week or two). Then I waste five minutes trying to remember where I put my cylinder-base wrenches, and another 15 minutes going next door to borrow a 5.25-inch ring compressor. And so it goes.

In other words, when I swing wrenches on my airplane, my work is careful, meticulous, strictly by-the-book ... and pathetically slow. I suspect the same is true of most owner-mechanics who only go through one annual inspection a year instead of dozens.

So unless you value your time at less than one-third of your A&P's shop rate, you're money ahead to let him do the work.

So Why Do It?

Good question.

I owned airplanes for 20 years before I first had any interest in picking up a wrench. I never would have guessed that I'd become involved in aircraft maintenance.

After owning a succession of single-engine airplanes, I bought my Cessna T310R in 1987. Eighteen months later, the A&P who had been doing my maintenance relocated, and the mechanic who took his place was relatively young and inexperienced and made me a little nervous. So when the airplane went into the shop for its annual inspection, I decided to hang around and watch, just for peace of mind.

It wasn't long before "hang around and watch" turned into "hang around and help." Lots of mechanics wouldn't have put up with me, but this one did -- in fact, he seemed to appreciate my interest, and was very patient in answering my questions and showing me the ropes of basic aircraft maintenance.

Much to my surprise, I found the hands-on work oddly therapeutic -- a sharp contrast to my normal daily routine ("slaving over a hot computer keyboard"). I've always enjoyed learning new things (my wife calls me a professional student), and I found myself intrigued by how much there was to learn about aircraft maintenance in general and about my Cessna T310R in particular.

Over the next few years I found myself taking on more and more of the maintenance work myself, under the patient supervision of a succession of A&Ps. Clearly, I was hooked.

As I started doing more and more of my own maintenance, I discovered that my aircraft became mechanically better and better. In my past aircraft ownership experience, my airplanes always seemed to have a few squawks waiting for the next time the plane went into the shop. Now, even though the T310R was by far the most complex airplane I'd ever owned, I discovered that it was virtually squawk-free. When anomalies did arise, I'd find myself fixing them immediately, rather than letting them stack up.

So why consider owner-performed maintenance? In my case, the answer is "satisfaction." The satisfaction that comes from doing something with your hands; from learning something new and complex; from getting to know a complicated piece of machinery in a way that that cannot be achieved without taking it apart and putting it back together; and from flying a squawk-free airplane that receives the finest maintenance that dedication (not money) can buy.

Getting Started

Will aircraft maintenance give you the same kind of satisfaction that it does me? There's only one way to find out, and that is to try it. Remember, I never thought of myself as a wrench-swinging kind of guy -- until I tried it and (surprise!) discovered that I liked it.

Regardless of how you think you feel about aircraft maintenance, I strongly suggest that every aircraft owner go through at least one owner-assisted annual inspection. It'll cost you a week or two out of your busy schedule (consider it a novel vacation idea), and you'll learn more about your aircraft's design, construction and condition than you can possibly imagine. You'll also learn a lot about yourself. You might discover that you enjoy working on your airplane, maybe even that you've got a knack for it. Or perhaps that you hate it and/or have absolutely no aptitude for it.

I also suggest you learn how to do some basic preventive maintenance on your airplane -- at least how to change the oil and oil filter, and perhaps to clean, gap and rotate the spark plugs. This involves only a couple of hours of work -- even the busiest aircraft owner can do it over a weekend. The real beauty of doing your own oil and filter changes -- besides the fact that it saves you the hassle of taking your plane to the shop every 25 to 50 hours -- is that it forces you to remove the engine cowlings regularly and get up-close-and-personal with your engine. It's the sort of inspection that pilots really ought to be doing every preflight, but unfortunately can't be done on most of today's tightly-cowled aircraft except at oil-change time. Think of an owner-performed oil change as an "advanced preflight."

What Can You Do Legally?

The FAA has carved out a broad laundry list of so-called "preventive maintenance" tasks that a pilot-rated owner can perform on his aircraft without requiring supervision or sign-off from an A&P mechanic. The relevant regulation is FAR 43.3(g), which reads:

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.

The definition of "preventive maintenance" appears in Appendix A(d) of FAR Part 43, and most owners are surprised to learn just how much maintenance they're allowed to do on their own recognizance. As an owner/operator, you're permitted to:

  • Change engine oil
  • Replace fuel and oil filters
  • Service spark plugs
  • Service hydraulic fluid
  • Service battery
  • Lubricate just about anything
  • Change tires and tubes
  • Grease wheel bearings
  • Service landing gear struts
  • Replace fuel/oil hoses
  • Install safety wiring and cotter pins
  • Replace landing and position lights
  • Repair landing light wiring
  • Replace the battery
  • Remove and replace tray-mounted radios (except DMEs and transponders)
  • Change database cards
  • Paint anything except balanced flight controls
  • Repair upholstery
  • Replace side windows
  • Replace seats
  • Replace safety belts
  • Patch airframe, fabric

... and that's just what you can do on your own without a mechanic's supervision.

With the cooperation of your friendly neighborhood A&P, there's almost no maintenance task you can't do. Here's what FAR 43.3(d) has to say about that:

A person working under the supervision of [an A&P] may perform ... maintenance, preventive maintenance, and alterations ... 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.

In other words, you can do anything that your A&P will let you do (and agrees to supervise and sign-off). In this context, "supervise" means whatever your A&P says it means; the reg says he has to be available for consultation, but that doesn't mean he has to watch your every move or breathe down your neck. As you earn the trust of your supervising A&P, he'll probably let you do more and more of your own work and simply drop by to inspect it once you tell him you're done.

How do you earn your A&P's trust? Keep in mind that he doesn't expect you to be an expert -- in fact, coming across like a know-it-all is a good way to scare off your mechanic. What's most important is to demonstrate to your A&P that you know your limits, and that he can trust you to stop and consult with him any time you're not absolutely sure of what you're doing. Exhibit a careful, conscientious and humble approach, and your A&P will probably give you lots of latitude.

If I Ran The FAA

Note: digitally enhanced picture.

When I'm appointed FAA Administrator (and the way I heard it Marion Blakey barely aced me out), one of the first things I'll do is issue an NPRM proposing some sort of "limited repairman certificate" that would allow a maintenance-knowledgeable aircraft owner to maintain his own aircraft without A&P supervision. Builders of homebuilts have long had this privilege, and the new Light Sport Aircraft rules offer a similar privilege to owners of the smallest, simplest certificated aircraft.

But if you own a Skylane or a Centurion or a T310R and you want to do anything beyond the preventive maintenance tasks set forth in FAR Part 43 Appendix A(d), the FAA says you've got to be A&P -- or be supervised by an A&P willing to take responsibility for your work. Why?

Some years ago, I did jump through all the necessary hoops to earn my A&P certificate. It was a fascinating and challenging adventure, and I now carry my mechanic's certificate with great pride. But there's no doubt in my mind that earning the A&P is total overkill for an aircraft owner who simply wants to swing wrenches on his own personal aircraft.

In my view, maintaining a personal-use Cessna 182 shouldn't require 4,800 hours of supervised wrench-swinging experience or two years of A&P school. Nor should it require learning about turbine engines, pressurization systems, wood structures, dope and fabric, or air-cycle machines (just to name a few of the vast number of subjects on the A&P exam).

What it should require is an in-depth knowledge of the systems and procedures for maintaining a Cessna 182. Period.

I've spoken to several high-ranking FAA officials about the idea of a "limited repairman certificate" for owners of certificated personal-use aircraft. Their responses ranged from "don't hold your breath" to "over my dead body."

Well, Marion Blakey's five-year term as FAA Administrator is up in 2007, so maybe I'll have a shot.

See you next month.


Want to read more from Mike Busch? Check out the rest of his Savvy Aviator columns.