Plane and Pilot Magazine - MaintenancePlane and Pilot Magazine RSS feed Mon, 29 Dec 2014 00:10:04 -0800 <![CDATA[Engine Break-In: It's Easier Than You Think ]]> A proper engine break-in can go far in encouraging long engine life, low oil burn and reliable service
Perhaps more than some aviators, I'm often reminded how essential good mechanical work is on an airplane. Though I've been fortunate to fly a variety of aircraft in conjunction with overseas aircraft delivery and flight evaluation articles, my more normal rides are the same as yours—general aviation machines that don't need to work so hard for a living. Ferry pilots are well aware of the benefits of excellent maintenance, as they're sometimes forced to operate closer to the edge of the operational and systems envelope than some other pilots.

Delivery flying very often exposes pilots to the benefits/drawbacks of flying behind new or reconditioned engines. The benefits are obvious. The sometimes overriding drawback is the incidence of infant mortality, a tendency for engines to fail more often in the first dozen hours than in the next 500. To some limited extent, a proper break-in can shortstop that problem or at least reduce the chances of an early engine failure.

When the maintenance folks are finished rebuilding aircraft and engines, the pilot's job begins, and his may be the most critical mission, especially when it comes to breaking in new or overhauled engines. For about the last 25 years, I've done the majority of return-to-service test flying for Tom's Aircraft in Long Beach, Calif. Tom's shop works primarily on 300 and 400 Series Cessna twins, along with Caravans, Dukes, Barons, Navajos and the gamut of piston singles.

For that reason, I fly my share of test and break-in hops after an annual inspection or installation of topped or overhauled engines. Along the way, I've been privy to a library of tips and procedures from Tom's mechanics who always ride right seat on those flights. They record temperatures, pressures, rpm and other vital engine information, and make suggestions if something mechanical doesn't look right.

Perhaps surprisingly, the whole concept of engine break-in exists because engines are specifically designed for the break-in process. The engine's steel cylinders may appear to have smooth walls, but that's mostly an illusion. That's because a hone has been used to imprint microscopic grooves in the metal. The grooves act as tiny oil reservoirs that distribute lubricating oil along the surface of the cylinder. The piston rings are designed to travel the length of the cylinder and must hydroplane on that oil film throughout their travel. If there were no oil on the cylinder wall, the piston ring and cylinder would make metal-to-metal contact. Not a good thing under normal circumstances.

That's exactly the reason for the wise mechanic's advice that, "The worst thing you can do to your engine is start it." A cold start, especially one after several weeks of shutdown, virtually guarantees that all the oil has run down off the cylinder, so you'll be maximizing metal contact for at least several seconds. Read More...
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<![CDATA[Caring For Your Aircraft]]> Part V: Understanding your aircraft’s battery is simple, useful and important
The aircraft battery is a seldom-noticed and somewhat-ignored component of the machine’s life-giving systems. In past articles, we’ve discussed the aircraft’s ignition system, and noted that it doesn’t require a battery; the engine runs just fine with its magnetos creating the electrical pulses necessary to make the cylinders fire. But because few of us hand-prop airplanes any more, and because of our increased reliance on electronics and technology in the cockpit, the battery has become the star of the show in modern aircraft.

Our batteries—and in fact all batteries—essentially are energy-storage modules. In our aircraft, we rely on the battery to store enough energy, so when we turn the ignition key, there’s enough power to turn the starter, which turns the propeller and creates that initial spark that ignites the fuel-air mixture in the cylinders. Once the engine is firing on its own, the battery provides power to all the aircraft’s electronics, like radios, glass-panel displays, GPS units and the zillion other things in the aircraft that run on electricity.

Most think the battery’s job is done once the engine has started, since the alternator is now engaged by the turning engine and constantly feeds power to the battery and other electrical components. While that’s true, the battery still exists to provide emergency power in the event of an alternator failure. Anyone who has experienced an alternator failure at night knows the value of a well-charged battery.

Lead-Acid Batteries
Most of us are flying around with lead-acid batteries. While it’s true that most electronics have moved to nickel-cadmium, and more recently, Li-Ion technology, general aviation has stayed with lead acid for a number of reasons, including ease of maintenance and low cost. Lead-acid technology is robust, proven, and—like the lowly magneto—reliable. The technology is simple.

Lead-acid aircraft batteries contain six or 12 “flooded” lead-acid cells connected in a series to make a 12-volt or 24-volt battery (each cell is nominally rated at 2V). The cells are encased in a plastic container equipped with electrical terminals (or sometimes a receptacle for mating to the aircraft). Each cell consists of positive plates made of lead dioxide and negative plates made of spongy lead (a form of metallic lead). The “flooded” part refers to the electrolyte that fills each cell, made of sulfuric acid and water.

The positive and negative plates are separated by layers of polyethylene to prevent the plates from shorting together. Electrons flow from the negative plate, out the battery terminal to whatever electrical component is being powered, then back through the positive plate. The electrons leaving the negative plate cause an oxidation reaction that converts the spongy lead into lead sulfate. The gathering of electrons at the positive plate causes a chemical reaction that converts the lead dioxide into lead sulfate. The whole process continues until most of each plate is converted to lead sulfate and the battery is fully discharged.

Meanwhile, the engine is turning the alternator, which sends an electrical charge back to the battery, keeping it from discharging completely. During the charging process, current is passed through the cells in the reverse direction. The reverse current causes a reverse of the chemical reaction, returning the positive plates to lead dioxide and the negative plates to spongy lead. When this process is complete, the battery is fully charged. Read More...
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<![CDATA[Caring For Your Aircraft]]> Part IV: From selecting the correct grade to changing it at correct intervals, knowing your oil is important
Oil is to an aviation piston engine what blood is to the human body: a crucial element in keeping it alive. Though blood fulfills the task by carrying nutrients to the various cells in the body, oil accomplishes the same function by creating a microscopic film between metal parts that keeps them from grinding each other into oblivion from heat and friction. Oil also carries the nasty by-products of combustion away from the critical parts of the engine, and holds them in suspension until your next oil change. Oil also disperses the intense heat created during combustion. In all, oil is your engine's best friend.

There's much hearsay about engine oil and oil changes in the piston aviation world. It seems everybody has an opinion and advice, though much of it isn't based on fact or comes from old ideas. The oil we use in our airplanes today isn't your grandfather's oil (though many of us miss oil cans), and understanding modern techniques and formulations will help us squeeze more life out of our engines. In the end, isn't that what it's all about?

We were fortunate to talk with Paul Royko, AeroShell's Technical Manager of piston-engine oil, who speaks frequently at aviation events and conferences. Though he won't admit to it, Royko is something of an aviation-oil guru, and his advice is something all pilots can benefit from. AeroShell has been providing oil to aviators since they developed the first ashless dispersant aviation oil in the early 1950s. In the 1960s, Aeroshell made headlines again when they developed their now-famous Turbine Oil 555, which was created especially for the Concorde, and could withstand the high-bearing temperatures and stresses of supersonic flight.

"The best advice I can give to pilots is simple," says Royko, "Pick the proper oil for the conditions you fly in. The other critical thing is to change the oil and filter at the proper intervals, and finally, fly often. Those three simple things will extend the life of your engine and your oil, and will help you catch problems early."

How Oil Works

To put that advice into practice, it helps to understand the seemingly simple process of how the oil works in your engine. In a cold engine, the oil sits in the oil sump, pulled by gravity to the lowest point in the system. When you start the engine, oil is pulled out of the sump by an engine-driven oil pump. It's sent through the oil filter (or oil screen if you don't have a filter), and proceeds into the crankcase, where it lubricates the critical bearings and other components. Oil travels into the cylinders, where it creates a seal between the piston rings and the smooth walls of the cylinders, allowing compression to occur.

The oil carries away heat through convection as it travels through the engine. Typically, the oil will travel through an oil cooler, where air flow will carry the transferred heat away. Microscopic bits of metal that are the result of friction also will be carried away, and will end up in the oil filter.

<![CDATA[Upgrade Your Plane! Part III]]> Firewall forward—life after TBO In previous issues, we took you through upgrading an aircraft exterior (P&P Dec. 2009) and an aircraft panel (P&P Jan./Feb. 2010). Now, we go firewall forward.

When purchasing an aircraft, the selection criteria usually relate to mission capabilities such as seating capacity, speed, range, weather capabilities, etc. Consequently, the first engine-related decision that most aircraft owners make comes at TBO (time between overhauls). Granted, there may be some decisions about engine replacement parts along the way, but by and large, what to do upon reaching TBO is a decision that always looms large just over the horizon.

For many owners, the TBO process isn’t fully understood. For me, researching my options made the decision at TBO clear. The nuances of the decision process are worth pondering. There are five basic options to consider upon reaching TBO. We’ll discuss each in detail so you can fully understand and appreciate the significant—and oft misunderstood—differences. To begin, we must first understand what the term “TBO” means.

Every engine is assigned a TBO value from the company that designed, certified and manufactured it. For piston engines, these values can range from 1,200 to 2,400 hours, with 2,000 being the most common. There also is a 12-calendar-year TBO for engines, which is largely ignored. Regardless of whether it’s based on calendar years or running time, the TBO value really is nothing more than a recommended service interval assigned by the manufacturer. The TBO is neither a manufacturer guarantee that the engine will last that long nor an FAA-required maintenance interval (unlike an FAA-mandated annual inspection). TBO simply is an original equipment manufacturer (OEM) recommended service interval with a margin of safety built in.

<![CDATA[Airplanes, Cars—What’s the Difference?]]> What you need to know, on the road and in the airairplanes vs carsWhat’s the difference between car (or motorcycle) engines and aircraft engines? It’s a perennial question with a series of stock answers, none of which is sufficient.

It’s as obvious as asking the difference between cars and airplanes, but it’s as technical as explaining the differences between car pistons and airplane pistons. The quick answer is, “They do different things.” The longer answer is more interesting, so let’s get right into it.

Demands differ. It takes 12 to 15 horses to run a small car 60 to 70 mph (cruise speed), and the car’s peak horsepower is 10 times that. Cars never run at full power for more than a few seconds; airplanes may use 100% all the way to cruise altitude. The car spends a lot of its life at a 10% power setting; an airplane at 70% to 80%. Also, part of the drag the airplane engine overcomes is due to a wing’s requirement to produce lift (tires produce all the lift a car needs), so the engine isn’t just moving the airplane through the air, it’s also holding it up. With a helicopter hovering OGE (out of ground effect), this is more obvious, though the principle is the same as in an airplane.

Duty cycles differ. Two thousand car hours typically represent between 70,000 and 100,000 miles, about half the car’s expected life. With a piston-airplane engine, 2,000 hours is about all we expect. On the other hand, the car will run out that mileage in five to seven years; a GA airplane will last 40. Airplane engines are used infrequently, hard and for relatively short times, all of which promote additional stress and wear.

Operating environments are different. While it’s no picnic under the hood of a car, it’s worse inside a cowling. Particularly with air-cooled aircraft engines, temperature stresses and rates of change can be enormous. A 100-degree day on the ground can be below zero in mere minutes at altitude. Rain can shock unshielded air-cooled cylinders and heads. Manual operation of aircraft cooling systems (e.g., cowl flaps) means that these systems are operated suboptimally at best and incorrectly at worst, introducing additional stress.

Operators are different. Finally, we see a factor in favor of the aircraft engine! In general, pilots are better attuned to their engines than are car drivers. Offsetting this advantage, though, is the fact that pilots face more demands from their engines, which require more attention and are fussier about fuel type and grade, throttle and mixture settings (to say nothing of prop settings!), and temperature management, all of which are irrelevant or automatic in modern cars.

Maintenance is different. Modern cars don’t need “tune ups.” Unleaded gasoline, modern electronics, improved metallurgy, and constant design and material enhancements have coalesced into today’s modern engines that require only periodic fluid changes to stay healthy above 100,000 miles. Airplane engines have few of those advantages, but they do receive a professional look at least once a year—something car engines don’t get (and usually don’t require).
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<![CDATA[I Need A Price Check On Runway 6, Please]]> User fees have the potential to significantly change the way we flyI Need A Price Check On Runway 6On February 5, 2007, President Bush released his 2008 fiscal year budget. Fears of how the budget would affect aviation came to fruition with a proposed budget cut of $1 billion off of the present funding level of $14.3 billion. A week later, the government declared that they’d be looking for a closer matching of costs to benefits; additionally, they recommended increases in the fuel tax and the implementation of several user fees. To make matters worse, if the budget goes through as presented, general aviation will be at war with commercial aviation about who and how much each side will have to pay for the right and privilege to fly. And the clock is tickling—funding for the FAA expires on September 30, 2007.

At stake is the cost to run a branch of the government, the FAA, which has approximately 14,500 air traffic controllers watching over almost 3,400 airports in 316 ATC facilities throughout the United States. As a side note, our ATC force is beginning to age. By the year 2015, approximately 75% of the controllers will be eligible for retirement. This creates a demand for 11,500 new hires over the next 10 years, which equates to an average of 1,150 new jobs per year. If a career as an air traffic controller is in your blood, now is a good time to submit your employment application.

The proposed 2008 federal budget has the potential to stymie general aviation with expenses and fees in much the same way the issue of product liability affected aviation in the 1980s and 1990s. If you remember, aircraft manufacturers pretty much ceased to produce single-engine aircraft because of the exorbitant product liability insurance costs that were tacked on to the cost of producing an airplane. So, we went through a period of several years when we were flying around in airplanes that were beginning to age, and there were no replacement airplanes on the production line.

Presently, the FAA gets funding from two sources: excise taxes from aviation taxpayers and a general fund that’s supported by all taxpayers. President Bush is expecting the users of aviation services to pay for the cost of those services. But just who are the users of aviation services? We’d all agree that pilots are users. Commercial passengers are users. But what about the economic impact to a community in the form of businesses and jobs that are generated by the aviation industry? If you remove pilots from the equation, then you’ll rapidly remove aviation from the community.

The FAA projections of this budget indicate that piston-engine pilots will see a tax increase of $100 million, or a 344% increase. Turbine aircraft are projected to see a tax increase of $868 million, or a 333% increase.

Fuel taxes are being targeted as an additional source of funds. Under the proposal, the current tax of 19 or 22 cents per gallon would be raised to more than 70 cents per gallon. This doesn’t sound like much—only 50 cents a gallon—until you start computing the gallons consumed on an hourly basis. Keep in mind that the average GA flight is between one and two hours. Then you have to get back home. Businesses will reflect this extra cost of doing business in the price of their products. To me, this sounds like the inflation that the government says it wants to keep in check.

But what about nonbusiness pilots who fly for pleasure. Many of these pilots may be wealthy, by someone’s standard, but there are other pilots with “normal” levels of income who spend their disposable income on flying. That $100 hamburger is going to cost a whole lot more. These pilots are the heart and soul of general aviation. They’re the pilots who generate an economic impact to their community by using aviation goods and services provided by local aviation businesses.
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<![CDATA[How To Keep Older Aircraft Flying]]> A new proposal offers some hope for owners of America’s aging aircraft fleet

How To Keep Older Aircraft Flying

It’s a sad state of affairs when it’s far easier for older pilots to have new knees installed in their vintage bodies than to have new fuel valves installed in their vintage airplanes. It’s, however, becoming an unfortunate reality, as the general aviation fleet grows progressively older and accessing “approved data” becomes more difficult. But now a glimmer of hope is on the horizon for those owners who wish to safely and legally maintain and upgrade their antique, classic and vintage airplanes.

Before looking at the possible solution, it’s useful to take a closer look at the situation. According to the FAA, the average age of the American general aviation fleet in 2000 was 30 years old. By 2020, the average age will likely be 50. As it is, many of those airplanes no longer have the active support of their original manufacturers, and that’s a problem with little hope of improvement.

In fact, many companies that once worked so hard to gain type certificates for these planes have long since gone out of business. Fearful of liability problems, some of the companies still in business are reluctant to provide the data. Based on the advice of government lawyers, the FAA has also decided that it will not release the approved data it holds, which only adds to the problem. Yet, at the same time, it requires owners and mechanics to use approved data for the maintenance, repair and restoration of older aircraft. This is the classic Catch-22 now facing owners of vintage airplanes.

Ironically, owners of aging aircraft have compounded the problem by doing a great job of maintaining their airplanes. Through diligent upkeep, the support of type clubs, and field approvals to install modern, improved parts, owners have played a significant role in extending the lives of airplanes that weren’t designed to fly after 50, 60 or even 70 years.

But, as careful as most owners have been in assuring that their planes are airworthy, over the past few years, several high-profile accidents have brought increased scrutiny to what is now termed the “aging-aircraft” issue. Vintage-aircraft owners cry foul when the FAA points to a wing-separation accident involving a T-34 long used in simulated combat training to justify its increased attention to the entire T-34 fleet, and especially when that reasoning is extended to all older airplanes. Airplane owners point out that the vast majority of vintage airplanes are not now, nor have they ever been, subject to such stresses.

Owners say they simply want fair treatment, the assurance that egregious cases won’t be used as the basis for future rules, and a common-sense approach to repairing and maintaining older airplanes in the absence of “approved data.” Now, thanks to the aggressive advocacy of the EAA and its companion group, the Vintage Aircraft Association (VAA), a possible solution to the problem has been proposed.

For several years, the EAA and VAA have been petitioning the FAA for a method through which owners can get approved data, but with little or no success. The problem seemed intractable until the two organizations decided to try a radical new approach. Instead of trying to get data, they’ve proposed a new vintage aircraft certification category, which would eliminate the approved-data issue, and allow owners to work with their mechanics, using “accepted data” and practices (FAR Part 43).

Simply put, under the proposal presented to the FAA in March, owners could voluntarily remove their airplane from its current type certificate, and transfer it into the new certification category. It’s important to repeat a key word in that last sentence, and that’s the word “voluntarily.”

Earl Lawrence, the EAA’s vice president of industry and regulatory affairs, is one of the principal authors of the proposal, and from the beginning, he says he was well aware that aircraft owners wouldn’t take kindly to any new, mandatory solution. Beyond that, the EAA wanted to make it clear that this was the beginning of the process. Of the proposal and the reaction to it, Lawrence says, “It’s developing the debate that we wanted to get going. Some people have felt that we already wrote a rule and handed it to the FAA. But what we have done is present a proposal to get a discussion going because we wanted to address how we can keep these aircraft flying.”

The EAA summarizes their proposal this way: “Create a certification category that will give owners and their mechanics the ability to maintain vintage aircraft using safety-based form, fit and function criteria, as opposed to unavailable or outdated type-certificate data.”

The proposal will allow an owner of record to choose whether or not to place an airplane into the new vintage category, a choice that wouldn’t be reversible. The transfer into the vintage category would also mean the airplane couldn’t be used for hire. Except for owners who use older aircraft for commercial purposes such as ride hopping or flight exhibition, this would be a small price to pay for the proposed benefits.

To understand how voluntarily moving an airplane into the new category could be beneficial, it’s helpful to look at a real-world comparison between what’s being proposed, and what currently exists. Under current rules, an owner who wishes to install a part that’s not within the original type certificate, or has been approved under a supplemental type certificate (STC), must petition the FAA for a field approval. This is often an expensive and time-consuming process, made worse if the manufacturer of the part hasn’t sought approval from the Parts Manufacturing Authority (PMA). Under the proposal, if the owner’s mechanic is satisfied that the part meets the requirements of FAR Part 43 for “safety-based form, fit and function,” the part can be installed and a simple logbook entry made. Depending on the final form the proposal may take, it’s possible that the FAA may need to be notified that the work was performed, but no approval will be required.

Among the type club representatives in attendance at the March
meeting, initial reactions to the proposal appeared to be favorable. Gary Rankin is president of the American Navion Society, a group representing many of the owners of the nearly 1,000 Navions still flying. He says, “I came away feeling very optimistic that this proposal offers a long-term solution for those of us who fly older aircraft and want to upgrade and maintain them safely.”

Butch Joyce is the operations manager for AUA Insurance, a North Carolina-based agency long known for writing coverage for vintage aircraft, and is himself the owner of a vintage airplane. Stressing that he was speaking as an aircraft owner, and not officially for his company or its underwriters, Joyce asserts, “My personal opinion of the proposal as it was presented is that I don’t see a problem with it as an insurance issue. That’s because the airplanes would be maintained as they are now, and I think it would be an improvement since we’d have more current data.”

No one expects the FAA to take immediate action on the proposal—with the most optimistic hope for approval and implementation within two to three years. But in a hopeful sign, the EAA’s Lawrence noted that at the conclusion of the March meeting, working groups were established and immediately began the task of studying five key aging-aircraft subject areas, a process that will include serious discussions on the future of a new vintage-aircraft certification category. The groups were planning to reconvene as early as July’s AirVenture in a public forum for a review of their work.

In the meantime, as their airplanes age, vintage-aircraft owners must continue to work within the constraints of a lack of approved documentation, and of contradictory regulations requiring such documentation. For the long term though, optimists such as Earl Lawrence see a real possibility that a unified general aviation community of owners, type clubs and industry leaders can convince the FAA that the proposal will improve safety, guaranteeing its success.

<![CDATA[How Old is Too Old?]]> A number of recent airworthiness directives for the general aviation fleet seem to be directly related to the aircraft’s age and flight time. So when is it safe to fly an aging plane?
How Old is Too Old?
Many of the most celebrated aircraft in the general aviation fleet have eventually shown signs of their age, like the Beechcraft V-tailed Bonanzas.

When you’re talking about the age of airplanes, you’re actually discussing a couple of factors that are intertwined—hours and condition—and each seriously affects the other. There’s yet another subset of factors that should be considered, however—the material the airplane uses in its construction: aluminum, steel, wood or composite.

Let’s talk about the different materials first. Aluminum is, hands-down, the most common airframe material with which most of us will interface, although in the more sport-oriented fields, we’ll run into lots of steel and a little wood. Composites are something of a wild card because they’re so new that we haven’t accumulated enough hours or years to make definitive statements about aging, other than they don’t rust.

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<![CDATA[Money-Saving Maintenance]]> A forum of experienced A&P mechanics and IAs pass along tips to preserve the value and airworthiness of airplanes in the most cost-effective way

Money-Saving MaintenanceThose pilots who have ever found themselves paying huge chunks of money on maintenance bills know that they can get quite expensive. What most people don’t realize, however, is that there are other simpler and less expensive ways to save on aircraft maintenance bills—and it all starts with the aircraft owners and operators themselves. Just take a look at some mechanics’ advice on how you can prevent that dreaded maintenance bill from ballooning. The money you save in the end will be well worth it.

It may surprise you, but the first and foremost thing that any aircraft owner and operator can do is to make sure that their aircraft has a complete set of logbooks. It’s a 100% owner and operator responsibility (according to FAR Part-91) that doesn’t always get the adequate attention that it needs. All records and logbooks need to be treated as someone would a wad of $1,000 bills because that’s what they essentially equate to. Nothing much else can certify the condition, quality and worth of an airplane. The value of any kind of airplane can be increased or drastically reduced based on the quality, condition and contents of these records. So don’t underestimate the importance of keeping records up to date, orderly and secured.

In a recent discussion with some A&P mechanics and IAs, changing the engine oil on a regular basis was their number-one response to what aircraft owners should do in order to prevent costly repairs and achieve maximum engine service life. Engine oil becomes contaminated with acids, water, carbon, metals and other contaminants through normal use and flying, which can cause accelerated wear and deterioration. How often to change the oil depends on the conditions under which the aircraft is operated, but a general rule is every 50 hours for aircraft equipped with a full-flow filter, and every 25 hours for those with only an oil screen, or every four months, in any case.

Next on the list, as elementary as it may seem, is to keep your airplane clean and waxed. A clean aircraft looks nice, but there are several more valid reasons to keep it that way. Dirt and grime on airframe surfaces, around rivet heads and in seams hold moisture that invites corrosion to set in. A clean, waxed aircraft also is more aerodynamic and allows easier detection of defects and leaks. Keeping an aircraft clean and waxed should be a regularly scheduled maintenance task and shouldn’t just be something to do when you have some spare time. After washing an aircraft, it should be greased and lubricated, and the pitot static ports should be checked for obstructions. While you’re at it, thoroughly inspect the whole aircraft for any deep scratches or abrasions, and if any are found, take care of them as soon as possible. At a minimum, sand down the area to remove any roughness or burrs, and touch it up with paint. This is important because most aircraft are constructed primarily of 2024-T3 aluminum, which has a thin cladding of pure aluminum on its outer surface that resists corrosion, but the cladding is just a couple thousandths of an inch thick. Below that layer is an alloyed metal that’s susceptible to corrosion. A deep scratch exposing the alloyed metal can eventually cause measurable harm and be expensive to repair. Keep in mind that corrosion is irreversible, and that surface protection is the best method of preventing it.

Taking good care of the aircraft records and logs, changing the engine oil and keeping an airplane clean and waxed are three fundamental actions that every owner can take to maximize his or her aircraft’s service life. If you’re the type who wants to get serious about maintaining your aircraft in tip-top condition and avoid costly unscheduled maintenance expenses, however, there’s much more that can be done. FAR Part 43 authorizes holders of a private-pilot certificate under Part 61 to perform preventive maintenance on any aircraft that is owned and operated by that pilot, as long as it isn’t used under Part 121, 127, 129 or 135. It also provides a real thorough list of more than 30 preventive maintenance tasks that can be accomplished as long as they don’t involve complex assemblies. Remember that the key words here are “preventive maintenance”—which actually means maintenance tasks that are done to prevent wear and deterioration. For one thing, you can change your engine oil yourself for a fraction of what it costs to have it done.

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<![CDATA[Just Tires?]]> Very few pilots realize how important they really areWhen we were student pilots, we were told to check the tires for condition and inflation before each takeoff. But as we progressed in our flying careers, some of us have taken tires for granted. Sure, we’re careful to check the “important” stuff—engine oil, fuel, headset batteries and radios—but we keep tires on a second-class status, merely glancing at them to make sure that they’re all accounted for and aren’t flat.

Continuing this bad habit, however, does have serious consequences. So perhaps it’s time to go back to the basics and take a look at tires in a whole different light because, in the whole scheme of things, they’re just as important as the rest of the components of an airplane.

The Trouble With Tires
For most of their lives, airplane tires don’t do much except keep the metal parts of the airplane off the ground. For brief periods, though, they work hard—especially during taxi, takeoff and landing. As airplanes get heavier, the margin in the tire loading goes down; as airplanes go faster, the margins become even thinner. With a high-performance airplane, the tires aren’t underutilized; in fact, they’re at their optimal design point—neither too large nor too heavy—for their intended task. That means that the tires need to be kept in excellent condition, and one way to assure that is to check the inflation, which, according to industry experts, is the single, most important parameter of a tire’s life, load, maintenance and safety.

One thing to keep in mind is that tires leak. Industry standards permit as much as a 5% pressure drop per day. So that means that even if you had an annual a week ago, your tire pressure doesn’t count for anything today. Even “perfect” tires can lose 1% to 2% of their pressure a day; and if the temperature changes dramatically, the air in the tires expands and contracts all by itself. And hours after you’ve checked your tires, a drop in air temperature can reduce the tire pressure to a dangerously low level.

It’s possible to overinflate, too. Not only do you run the risk of having the tire and/or wheel explode with tremendous force, but you also can get some undesirable handling.

Cody McCormick, an insurance underwriter who was the ground control approach chief at Troy, Ala., remembers, “I saw a guy with a new Maule with tundra tires on it down in KTOI. After about 10 touch-and-goes [with the tires properly inflated], he decided that he didn’t like the look of the soft tires, so he put about 24 pounds in them. He did 10 touch-and-goes on his next landing—I’ve never seen an airplane bounce so high so much, so far.”

But what about using nitrogen? Rob Robson, Goodyear’s aviation tires product support manager for North America, says, “If you can get dry nitrogen, that’s a good thing because it reduces corrosion on wheels. Oxygen also can affect the rubber. And nitrogen has the additional benefit of being non-combustible.”
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<![CDATA[An Advanced Course In Engine Management]]> When you have to pay for fuel, repairs and overhauls, you’ll want to treat your powerplant to the values of science, not hearsay
An Advanced Course In Engine Management
GAMI uses its two-cell engine test-stand to analyze its engines, employing unleaded autogas, a new spec unleaded Avgas and 100LL. The company also performed FAA certification testing for Superior’s new XP-360 engine on one of its test stands.
Today, bookstores have shelves of self-help and how-to books targeted at people just like me. You know, books like Brain Surgery For Dummies, Taxes For Dummies or The Idiot’s Guide To Juggling. There is one guide, however, that you won’t find in your local bookstore or, unfortunately, at your local airport. The Advanced Pilot Seminar (APS), better than books like Engine Management For Dummies, can only be found in Ada, Okla.

Walter Atkinson, George Braly and John Deakin developed the definitive course on Aviation Piston Engine Management. If you trust your life to a piston engine, it’s a course that you should take. Braly provides the science and the hardware to the course, Deakin brings years of experience and Atkinson puts all the pieces together. Their Advanced Pilot Seminar is a direct outgrowth of the GAMIjector/lean-of-peak controversy. In short, the seminar, given every other month, takes engine management from a black art to a science.

For instance, would you like to know how to lean for density altitude, any density altitude, for any engine? The Advanced Pilot Seminar will tell you how.

In most hangar-talk sessions, these three men are the high priests of lean. But contrary to some pundits, they do not preach a faith based on leap-into-lean operations. They rely on science to answer the difficult questions; for them, theory must conform to facts and reality.

It all starts with what we know or what we think we know. Almost all airplane engines operate in a very harsh environment, sitting on a sun-baked ramp for days or weeks at a time. Languishing for months, they soak in the cold during bitter winters. After sitting mutely for long periods, they start in seconds, with temperatures rising from ambient to over 1,500 degrees. With minimum cooling, they produce 100% power for takeoff, followed by hours of high-power operation.
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