Left Seat: What Really Kills Airplanes

Sitting idle and accumulating maintenance bills are taking their toll on the fleet of existing airplanes, and many will not survive the recession.

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Boeing B-52

Airplanes can live such extraordinary lives; it seems that many will never die. Martha Lunken reminds us frequently that 70-year-old DC-3s are still flying and working for a living. The B-52 bombers are often twice the age of their pilots but the old Boeing flies on. And 50-year-old Bonanzas are not exactly rare.

The remarkable restorations we see every year at Oshkosh, Wisconsin, prove that an airplane's life does not have to end because of old age. The number of flyable warbirds, all more than 60 years old, grows, not shrinks, every year. The same is true for other rare antique airplanes. But some airplanes do not enjoy such longevity. What is it that eventually kills off most airplanes while allowing a chosen few to fly on? The answer is a battle between economics and love of the airplane.

The economic forces can be seen most clearly when it comes to airplanes that work for a living. Maybe one or two of a type will be preserved when the balance sheet shows a working airplane is no longer earning its keep, but the vast majority are junked. Think of the beautiful Lockheed Constellations that most of us think were the most graceful of the big piston-engine airliners. A couple still fly to preserve memories and introduce a new generation to a bygone era, but none earn their keep.

Economics also plays a role in which airplanes the military chooses to keep flying. For example, the oldest T-38 advanced trainers are coming up on their 50th birthday but the Air Force plans to keep them flying for many years to come. It's a simple choice for the brass. A new trainer would take more out of the budget allocated by Congress than it costs to keep refurbishing and maintaining the T-38s. And unlike the high-tech new fighters the military covets, a trainer is, well, still a trainer, and the T-38 has proven to be very successful in its mission.

The airlines also respond directly to economic forces when choosing to retire or keep flying certain models. For example, when the rules changed to allow two-pilot crews in even the largest jets, it became very uneconomical to keep flying older airplanes that required a crew of three. Add pilot costs to the lower fuel efficiency of the older engines, and Boeing 727s, 747s and 707s disappeared along with DC-10s and others in very short order.

Sometimes modifying older airplanes overcomes their economic disadvantage. FedEx converted several airplane cockpits from three- to two-pilot configurations and modified engines so 727s and DC-10s still carry the packages on that line. Replacing the engines on the DC-8 with new efficient turbofans gave the DC-8s many more years of life in cargo service. Until fuel prices soared, the early small DC-9s made sense for some airlines after refurbishment, delivering more for the buck than a new 737 or 717.

But another element in the economic equation for jets is inactivity. You would think parking a jet, or at least flying it infrequently and preserving it carefully would stop the costs from rising, but it doesn't always work that way. The reason is that every important system and structure on the airplane has calendar as well as flight time limits. Inspections, overhaul or replacement come due on a jet sitting around at some certified interval even if it hasn't flown. The maintenance requirements are almost always a number of months or years or flight hours, whatever comes first. Those are very real costs that must be paid before the jet can be returned to service or be kept airworthy while flying little.

With the big drop in flying that has occurred during the recession, the calendar time factor is going to become an issue for many nonairline turbine airplanes. The longer a jet sits, the more the bill for calendar-time-required inspections and replacements piles up, driving down its value. At some point market forces and the cost of the work required to return the jet to service converge, and the airplane becomes essentially worthless.

The other big issue ushering aging jets to the grave is the vast improvement in engine and wing efficiency over the past 30 years. Jet airplanes designed in the 1950s and 1960s were essentially as fast as today's airplanes, but they achieved that performance with brute thrust. Jet fuel was cheap and the turbojet used a lot of it to go fast.

Light airplanes -- those with maximum takeoff weight below 12,500 pounds -- do not typically have the same calendar-related costs, and there has not been a significant improvement in fuel efficiency in more recent designs. For most light airplanes there are no "hard" limits on airframe, system and engine components. Retaining the value of a light airplane as it sits is more a matter of proper storage than of regulatory compliance.

For example, if a light airplane is kept dry in a hangar away from the damaging effects of sun, rain, snow and wind, the airframe and its components will suffer very little deterioration. Piston engines can be successfully "pickled" with special oil replacements that fight off internal corrosion.

To return a light airplane to service after long storage typically requires nothing more than a very detailed inspection by a mechanic who holds an FAA inspection authorization (IA). In other words, it needs an annual inspection, even if the most recent annual had been done many years before.

Of course, some components can decay even while properly stored, and those will be found and replaced during the annual. If the airplane has been left sitting outside, all bets are off because moisture intrusion will almost certainly have caused corrosion, and UV radiation from the sun will have damaged the nonmetal parts. In that case, the cost of required repairs could easily exceed the value of the airplane once it is returned to airworthy condition.

As I fly around the country with very little activity on the controllers' frequencies and see empty ramps that were once busy, I have come to believe that we are seeing the death throes of a large part of the general aviation fleet. With the average age of piston airplanes well over 30 years, it should come as no surprise. Except it is a surprise because nobody thought airplanes would last as long as they have. They could go on indefinitely, except for the lack of use.

For a long time people have been forecasting that the general aviation fleet is so old it must be replaced. I believe this recession will make that prediction come true, but oddly not because of age or because the airplanes are wearing out. It is really lack of use, and thus lack of proper storage or continuous maintenance, that will do them in.

Not all old airplanes will succumb. Those regularly used and loved will fly on for decades to come. And the passing of those relegated to the far corner of the tie-down area will really be an acknowledgment of a death that happened some time before. This recession is bringing a changing of the guard, and a mixture of new airplanes, and carefully maintained ones, will fly on in greater numbers when the economy recovers.

New Owner, New Look

In June, Flying was sold to Bonnier Corp., a big, family-owned media company based in Sweden. Over the past few years, Bonnier has been investing in special-interest magazines here in the United States and now has nearly 50 different titles. You have no doubt heard of many of the magazines, such as Field & Stream, Popular Science and Yachting. The magazines cover a wide range of interests, from cooking and parenting to fishing and skiing, but in every case they are dedicated -- just like Flying -- to readers passionate about their favorite activities.

You will notice the familiar names in this issue, and the range of topics is what you have come to expect from Flying. But I'm sure you will also notice a new look in both the graphic design and the quality of the paper.

Bonnier has invested a significant amount of money to upgrade the paper stock and to return to the so-called "perfect" binding that we used until earlier this year. The new paper is much heavier and whiter. The airplane photos look much better on the new paper. You will also notice that the cover of your subscription copy is now shiny, with a special coating to protect the surface and make the image sharper.

These are very difficult times for both aviation and magazine publishing, but I am pleased to say Bonnier is making investments in Flying's future.

That's Why There Are Two

Not long ago I was headed home from Jabara Airport in Wichita, Kansas, when the routine mag check revealed a totally dead mag on the left engine of my Baron. When I rotated the switch to the "left" position, the engine died.

The engine had started normally on the good mag. What is more interesting is that I had flown maybe as much as three hours with one mag failed on the left engine and didn't know it. A couple of days earlier the mag had checked out fine before departure from my fuel stop in Indianapolis. The flight to Wichita was just over three hours, and during that time the mag quit. I didn't sense any change in engine operation; it was as smooth as ever, and there were no temperature indications and not a hint of a problem.

The mechanics at Midwest Corporate Aviation jumped on the problem quickly. The mag tester, which can find most failures, indicated the mag was performing normally. It wasn't. They removed the P-lead that grounds the mag to shut it off to see if the switch in the cockpit was the problem. It wasn't. Finally, they took the distributor cap off the top of the mag and found a bunch of strange gray debris inside the mag. Nobody had seen anything like it.

Further investigation found the coil -- the component that intensifies the electrical output of the mag to make the powerful spark -- had somehow shorted out to the case. Instead of going out the leads to the spark plugs, the electrical energy from the coil was arcing to the inside of the magneto case and was being grounded right back into the engine.

Wichita is probably the only city in the United States where a magneto coil is on the shelf and available, so I was in the air after only a couple hours delay. But everyone remains puzzled because it was a brand-new magneto with barely 100 hours and less than 10 months of operation. None of the Midwest mechanics, or those at my home shop in Hartford, Connecticut, had ever seen such a failure. Coils sometimes break down inside and the electrical current can no longer pass through because the circuit has become open. But nobody had seen a coil short out and arc to the case.

The mag is a Slick. Either Slick or TCM magnetos can be used on the Continental engines in my airplane. The company offered a warranty on the coil, and I'm sure it will investigate the cause of the failure. But the problem was another reminder -- in case one was needed -- that dual ignition is a must, and that new is not always better than a component performing normally.