As the student moves through primary training, though, preflights are apt to devolve into ritual. Yeah, the wings are still attached, and there’s oil in the engine. Let’s fly!
This is less of a problem in the context of a busy flight school, where each aircraft is likely to be scrutinized by several different students and their instructors in the course of a day and 100-hour inspections can come as often as every few weeks. But habits made as a student tend to carry over after a freshly certificated pilot goes out into the world. Out there, perfunctory preflights invite trouble. How much trouble? In an average year, 30 airplanes and a handful of helicopters are wrecked because their pilots missed discrepancies that should have either been fixed on the ground or grounded the flight.
Some could have been fixed pretty easily. The Mississippi-based owner of a Cessna 182 got the same lesson that the Alaskan pilot of a Piper Super Cruiser learned about a month earlier: The engine won’t keep running long with the fuel selector turned off. It will, however, run just long enough to get you off the ground and into a really awkward situation. Both airplanes had just been returned to service after annual inspections; the mechanics had turned the fuel off. (Both mechanics also insisted that they’d told the owners about this.) Anybody seen that before-takeoff checklist?
Fuel system problems figure heavily in the history of inadequate preflights, and most aren’t a great deal more complicated. The most common, of course, is not determining exactly how much fuel is on board. If you don’t know how much you’ve got, how do you know it’s enough? After his forced landing, a Navion pilot told an FAA inspector that, “Had I had another five gallons in the tip [tank], I would have been OK.”
Water contamination is another perennial favorite. If the airplane has been sitting on the ramp through four days of Florida thunderstorms, you think you might want to check the tanks? (And maybe drain a little from the gascolator on top of the tank sample to make sure they’re the same color? A tube of pure water looks a lot like a tube full of avgas.) And unless fuel is already dripping out of them, it’s worth teaching your students to take a good, hard look at those vent tubes while they’re under there. Various tiny critters like to crawl in and take up residence, leading to fuel starvation as vacuum builds inside the tank. The owner of one Rutan Vari-Eze prevented this problem by putting a black rubber cap on the tube, which worked beautifully. It would have been even better if he’d remembered to take it off again one August afternoon. When the engine quit at 2,000 feet he knew exactly what the problem was, but couldn’t do anything about it in the cockpit.
Losing an engine is bad, but a flight-control failure can quickly become catastrophic. While things can break or jam in flight—most often because loose items get stuck in inconvenient places—the problems were usually apparent on the ground, or would have been if the pilot had bothered to look. A Twin Otter freighter making the short hop from Hyannis to Nantucket, Massachusetts, lifted off early and rolled left until it crashed. Investigators found the lower control lock still installed—the same mistake that has destroyed aircraft from Skyhawks to King Airs, usually with fatal results.
Other discrepancies were a little more subtle but no less disastrous. A planned photo shoot at the 2009 Sebring Sport Aviation Expo turned deadly when a Remos GX rolled right uncontrollably immediately after takeoff. It turned out that when the factory crew unfolded the wings, they’d neglected to connect the left aileron. A Washington owner restoring a Piper Super Cruiser had a history of doing crow-hops before the airplanes had been inspected; when his IA took him to task, he smiled and said, “It hasn’t killed me yet.” It did the next time. The PA-12 pitched up to a near-vertical attitude before stalling in. It turned out that he’d connected the elevator cables backwards—the third time he’d reversed cables on an airplane he was working on.
By the time they started the take-off roll, each of these pilots should have checked “flight controls free and correct” twice – once during the walk-around, and again during the runup. Are your students learning to believe that everything will always work as long as the wings haven’t fallen off? There’s a lot to be said for having your instructors take pains to get their attention. While you don’t want them draining the oil or putting water in the fuel tanks, there are other ways. They can always ask the previous instructor to pull a breaker or two. Loosening some fasteners is OK provided you remember they’re loose. One DPE of our acquaintance liked to get out to the field early and stash a rubber chicken somewhere around the airplane—under the cowling, or back in the tailcone. If the student didn’t find it, the flight portion of the checkride would usually be postponed.