Methusaleh on Wings

Last week’s downing of a Turkish Phantom F-4 fighter-bomber by Syria indubitably marked a political turning point in the region. But as I read about it, I couldn't help but wonder: An F-4? Really?

Yep. As it turns out, the McDonnell Douglas Phantom F-4 is still flying in half a dozen air forces, including Turkey's, according to Wikipedia.

That’s pretty impressive, as it’s been 52 years since the plane first entered service with the U.S. Navy. Hah, that’s nothing, harrumphs the old pilot in the back of the room: The Boeing B-52 Stratofortress, first flown in 1955, is expected to stay active right into the 2040s.

How do airplanes keep flying a lifetime after the first copy rolled off the line?

There are many ways to answer that question. You can speak of the mechanical fortitude of planes, some of which really do keep on taking off and landing when their original pilots are in the old folks’ home. That’s what happens when you engineer something to the extremely high specification it needs to fly. In the air, you know.

Or you can talk about the robustness of the underlying design. Here your line of patter touches on how the airframe—the one part that hasn’t been swapped out, tacked on, or improved—is just about as good as anything we have today, at least for plain-vanilla flying (as opposed to, say, radar-eluding stealth). By up-arming the thing we can still use it as a “platform,” as they say, particularly for standoff weapons—missiles that can be fired from a safe enough distance to allow even a 1950s-era plane to get away.

But the fun way to answer the question is to refer it to a similar one posed long ago, and in another field entirely. Why, biologists once asked, do birds live so long?

There is a rule of thumb in biology that the body size of a species correlates with its lifespan. A mouse, even a coddled one, is lucky to last a year; an elephant can get to 60; a whale, to 90.  But, strangely, if you graph body size against lifespan you get two parallel upwardly sloping lines--one for mammals and another one, much higher up, for birds. Parrots often live as long as elephants. Pound for pound, birds outlive mammals by a huge margin.

But not all birds live long and prosper. Landbound species like ostriches last no longer than mammals of the same size. So it turns out that it’s the flying part that’s critical. Indeed, the one category of flying mammal—bats—lies smack dab on the bird trendline, too.

The great biologist William D. Hamilton once suggested that it could be that birds were simply engineered better--like airplanes, he said. Or—and you could hear the drumroll, because this was his real belief—it might instead have to do with the enhanced ability of a flying animal to escape predators. When violent death is less likely, natural selection will favor those individuals that take some energy away from breeding and put it into the repair and maintenance of their bodies.

The Phantom jet is a faintly parallel case. Today it survives precisely in those air forces that do not expect to use it to establish air superiority by going after enemy fighter jets. It survives as a weapons platform, as a means of showing the flag, and as a way of observing the other side (apparently, that’s what the Turkish Phantom was trying to do).

Flying is just one way to stretch out the longevity of an animal. You can also use brains and technology to get to the top of the food chain, as we human beings—a long-lived bunch—have done. Or you can use a hard shell to fend off predators, in the matter of the even more astoundingly long-lived tortoise family.

That reminds me: Just this week “Lonesome George” died. He was the last of his breed of Galapagos tortoise, having lived for about 100 years—most of them without any female companionship at all. It must have seemed like 200 years.

Images: putneymark/Wikipedia

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