Inspecting the Powerplant

At the front of the plane, the pilot carefully inspects the engine, making sure the oil is full and there aren’t any leaks—the same sort of common – sense checks you might make on your car. But the airplane has something else up front, of course, that you don’t find on many cars: a propeller.

The propeller is vulnerable to a lot of damage and has to be inspected carefully, even though the check only takes a few moments. The propeller’s leading edge can become badly nicked and pitted from small stones that it sucks up. A large rock can even

crack a prop blade. So a pilot has to check the leading edge for dangerously deep pits or for cracks that could cause part of the prop to break off in flight.

Inspecting the Powerplant

By the Book

When mull Aifphnci ifc stored on the ground, even if it’* only for a few ml ли tct between flights, they arc secured by tie­down ropo or chains. Because airports are wide open spaces, the wind at an airport can be stronger than on nearby residen­tial streets or commercial districts; sudden gusts of wind can damage planes on the ground. Planes should always be tied down when there is no pilot at the controls.


That could be a catastrophe for two reasons. First, the prop’s thrust will decrease, maybe a lot, and that could mean the airplane can’t sustain enough speed to maintain a constant altitude. In that case, the airplane will begin do descend and the pilot will have to plan for an emergency landing.

Second, the loss of a part of the propeller will throw it out of balance and could cause an extreme vibration of the engine. If the pilot doesn’t respond quickly by reducing the throttle, the engine could be severely damaged or even damage the rest of the airplane with its shaking. Once the throttle is reduced to idle, or to whatever lower setting will cause the vibration to stop, the pilot will have to begin descending in order to maintain safe airspeed, and that means an emergency landing.

No matter what happens during flight to damage the prop, the result is an emergency landing. What better reason to carefully check the prop?

While he’s near the nose, the pilot will inspect the front wheel, or the “nose gear.” The tire should be fully inflated, have a safe amount of tread remaining, and there should be no oil or fluid leaking from the shock-absorbing piston that’s clearly visible just above the tire. Then, the pilot inspects the right wing in the reverse order he looked at the left one.

Finally, the pilot moves back over the empennage and around the stabilizers, checking that they are securely hinged and that they move freely. While he’s back here, he’ll disconnect the third and final tie-down.

By now, in the course of less than 10 minutes, the pilot has looked over the entire airplane, moving everything that moves, tugging on anything he can get a grip on to make sure it’s securely attached to the plane. Now it’s time for one last walk around the airplane. The pilot wants to make sure all the tie-down chains are removed, and the radio antennae are in place. And he wants to be darn sure the fuel caps are tightened all the way down. That completes the preflight inspection.

Inspecting the Powerplant

On Course

There’s a bi’t of folk wisdom among pilots claiming that the quickest simplest way to check a propeller for invisible cracks is with the flick of a fingernail. The theory goes that an undamaged propeller will ring like a bell, while a crack in the prop will cause more of a dull thunking sound. I’ve always found that a flick that is hard enough to "ring’ the prop is also hard enough to cause a good bruise under the fin­gernail. What’s more, I have a tin ear for a ringing prop, so I prefer to inspect the propeller visually.