Many of the most celebrated aircraft in the general aviation fleet have eventually shown signs of their age, like the Beechcraft V-tailed Bonanzas.

In just the last few years, a series of T-34s, the military equivalent of a Bonanza, have suffered wing separations. An emergency airworthiness directive (AD) grounded the fleet. Just a couple of months ago, a well-maintained T-6, a World War II trainer, lost a wing doing maneuvers over Florida. With the general aviation aircraft now averaging just less than 30 years of age, how can you tell if an airplane is safe to fly?

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.