Airframe and Powerplant

Get greasy, have fun — it's all in the name of education.

This is not a spectator sport. Flying calls on us to be involved, to take command lest we get taken for a ride. Taught early on to "fly the airplane" first, pilots strive to be in control and to oversee aircraft operation from preflight to tiedown. Psychologists occasionally apply unglamorous descriptions to this type of behavior, but we just think it's normal.

Yet when it comes to maintaining airplanes, we place matters into the hands of a mechanic. Come annual-inspection time, especially, we tend to drop by the maintenance hangar, hand over the keys and a squawk sheet, go home, and hope for the best.

That's not a bad move, mind you, because A&Ps are, as a group, skilled professionals having invested years of schooling and on-the-job training to be paid something less than wheelbarrows full of cash. Not only that, an A&P's signature in your airplane's logbooks puts him in the hot seat: Your airplane must be airworthy, both by the irregularly enforced Federal Aviation Regulations and by the absolutely enforced laws of physics.

For the mechanically inclined, however, there's much to gain by performing as much of one's own maintenance as the rules allow. Most important is the working knowledge you gain of your airplane and its systems. Reading the handbook or poring over the maintenance manuals positively pales in comparison to getting your fingernails dirty. Not only will you have a better feel for your airplane's maintenance needs, but you'll be in a much better position to diagnose problems away from home. It's the education that keeps on giving.

Naturally, you can't do all the maintenance unsupervised. FAR 43.3 and Appendix A outline preventive maintenance tasks that can be performed by the owner or operator. (A copy of FAR 43.3 can be found on p. 3-134 of the 1993 edition of AOPA's Aviation USA.) Take note that such maintenance has to be done according to accepted standards and practices and entered in the appropriate logbook.

Those items called out in Appendix A form a rather short list compared to the tasks an owner or operator can perform with a mechanic's supervision. According to FAR 43.3(d), "A person working under the supervision of a holder of a mechanic or repairman certificate may perform the maintenance, preventive maintenance, and alterations that his supervisor is authorized to perform."

Saving money isn't — and should not be — the primary reason for your participation. Mainly, the cost of parts — and the number of them needing replacement at the annual — tends to set the overall cost of the inspection. Many shops will charge you the full retail price on replacement parts. By doing supervised annuals, you can save typically 15 to 25 percent but as much as 50 percent on parts, depending upon where you shop. Check the pages of Trade-A-Plane for the larger discount houses.

According to how much of the work you're capable of and willing to perform, you can save a chunk on the mechanic's time, too. Don't expect to pay the A&P/IA for a half-hour's worth of peeking and prodding, though; a thorough inspection takes time, and because his signature's in the logbooks, he ought to be interested in carefully determining the airplane's condition.

If you're fired up to help out during the annual, here's what you do. First, find a mechanic or shop that will let you participate. Some have no interest in dealing with the aircraft owner except to cash his checks — forget them, and start asking around. One of the best sources here is the type club. Place a call to the group supporting your marque, and chances are excellent that someone there can refer you to a local, willing wrench. A few of these, like the Cessna Pilots Association, have in-house shops that not only encourage owner participation, but virtually demand it.

Calling on your type club for help gets you over the first hurdle — finding someone familiar with your brand of airplane. Of course, if you're flying a 172 or Cherokee, this is not such a serious concern because most A&Ps have at some time worked on one of these. But if you're flying a Mooney Mustang or a Twin Bonanza, it will be well worth your while to seek out a specialist. The more complex the airplane, the more important this is.

Eventually, you might gain enough knowledge of your particular airplane to compensate for a good wrench not intimately familiar with it. But until you do, stick with a practiced hand.

You might find a mechanic willing to perform the annual at your hangar — or less likely, at your tiedown spot — but this is not necessarily the best route. At some airports, itinerant mechanics are verboten; it's best to check with the FBO or airport manager first. Also, the inspection will require some special tools and equipment that might not be available on the tarmac. At minimum, you will need an air compressor, a full toolbox of standard and aviation-specific tools, and, for retractables, a set of jack stands. If the only tools you own can be found at the other end of the fuel tester, stick with the mechanic who will let you into his shop. He will probably charge you more for his time to help offset the overhead at the shop, but it will be well worth it.

Maintenance manuals are mandatory for the annual, so if you don't have them, get 'em. You will need the maintenance and parts manuals, as well as a current printout of airworthiness directives (ADs), service bulletins (SBs), and service instructions. There is a handful of reference works the maintenance-involved owner ought to have (see "Airframe and Powerplant: The Well-Read Aircraft Owner," March 1992 _Pilot_). The service manual will include an annual-inspection check list; let this be your guide. Also, if you think you'll be doing much of the work, bone up on Advisory Circular 43.13-1A, "Acceptable Methods, Techniques, and Practices," the mechanic's companion to the right way of doing things.

A good deal of time spent on any annual is given to examining the logbooks for compliance with ADs and SBs. (For Part 91 operators, no SB, including those labeled mandatory, need be completed for the airplane to be legal, but the modifications called out by many of them can improve reliability or durability, and so are worth examining.) This you can do well ahead of time, creating a list of current ADs and recurring ADs requiring compliance at or near this annual. Your mechanic will want to look over the logs, too, but you can save him some time by organizing the paperwork.

Before you meet with the A&P, have the normal-wear parts in hand. This means oil, oil filter, spark plug gaskets, and any other wear items called out in your maintenance manual. Also, by looking through the logbook, you will know if it's time to change the induction air filter or vacuum system filters or other periodically replaced items. This is where your homework can really pay off in parts preparation.

To help illustrate the benefits of the owner-assisted annual, consider the case of one particular Mooney 231. This is the airplane I fly most of the time; it is owned by Mark Reno, a certified Mooney aficionado and maintenance maniac. His attitude is enviable: If anything breaks, it gets fixed. We strive for a 100-percent airplane; everything works, no excuses. It greatly improves one's outlook flying over the Rockies at Flight Level 240.

Last year's annual was an odd one for this Mooney. As Reno was out of town, we decided to take it to a well-known Mooney shop. This facility performed an exceptionally thorough inspection and carried out repairs to the alternator, which had, in fine 231 fashion, grenaded itself after about 300 hours time in service. There were additional electrical system items to fix, as well as a few long-term maintenance details — like the oxygen bottle recertification and tail-pivot bushings — which came due as well. In addition, all six exhaust gaskets were leaking to some degree, and most of the 24 pushrod seals were weeping — chronic problems with the 231's Continental TSIO-360. The bottom line was nearly 58 hours of shop time, $1,700 in parts, another $500 for the oxygen bottle, and more than three weeks' downtime — the bill came to a bit over $5,200.

Part of the expense was lack of communication. With the owner out of town, items that did not affect safety of flight and might have been deferred were, in the absence of Reno's judgment calls, fixed or replaced. I have no qualm with the shop's desire to make the airplane "right," but it is possible to be zealous to the point of economic absurdity.

This year was different. With the help of Reno's friend — an A&P/IA — the annual was performed in the Mooney's hangar in three working days, two Saturdays and a Sunday. It could have been finished the first weekend if all the wear items had been on hand and if we didn't have to hunt around for jack stands. The A&P brought his tools — a suspension- sagging trunkful of them — and we had an air compressor and common hand tools in place. All told, Reno paid the mechanic for 14 hours' labor, approximately 10 for the inspection itself and the remainder for performing some of the repairs. Reno himself spent a total of three 12- hour days opening and closing the airframe and tending to some of the fixes.

To be fair, this year's annual was unusually squawk-free, largely because some larger repairs had been done along the way, like top-end work and a turbocharger replacement. (There's no way around it: The higher and faster you want to go, the more it's going to cost.) Replacement parts included brake pads, fuel cap O-rings, air filter, vacuum system filters, nose-gear wheel bearings, a few feet of SCAT hose, one turbine inlet temperature probe, one cylinder head temperature probe, and a big helping of miscellany like replacement hose clamps and tie-wraps under the cowling. Total cost for the hired wrench and parts — mostly purchased from one of the big discount houses — was just under $1,000. It would have been a bit less if an AD had not been published as the annual was progressing — it called for inspection of the TSIO-360's valve keepers. This added some last-minute excitement, but we ultimately discovered the 231's valves to be well kept.

There's more to this self-maintenance stuff than saving money, as mentioned earlier. New wear items that had not surfaced in the airplane's 10 years and 1,100 hours of life turned up — nothing major, just a few popped rivets in nonstructural members and the like — and made it into the supplementary annual-inspection check list made up by Reno. The airplane has been scrutinized by three sets of eyes, and its condition is well known by the owner and me. There's no worry of tools left in the intake plumbing or haphazard maintenance practices.

Such a happy turn of events at the annual, in this Mooney's case, was the result of frequent inspections and careful maintenance all year long. Attention to details during the year can make the annual experience easier to swallow and far more predictable. Performing that annual goes hand-in-hand with that philosophy. You get back in peace of mind and educational value for the time and effort expended.