Training and Safety Tip: Expect surprise
The engine was so “unreliable” that I could set my watch by its daily “failure.” Actually, there was nothing physically wrong with it. I just had one of those flight instructors who delighted in pulling the throttle with, “Your engine failed! What are you going to do?!”
The procedure that worked best for me was to roll my eyes, pitch for best glide, pick a field while simultaneously simulating restoration techniques on my perfectly good engine, and carry out a flow from right –to left. “Fuel selector,” I would say, waving my hand in the general direction, “mixture, throttle, mags, primer… No go. Puttin’ her down.”
There wasn’t really anything wrong with this training, other than it was overdone. A real engine failure is a rare thing, which is actually what makes it so dangerous: It catches you by surprise.
My instructor was preparing me for mechanical failures, which are even rarer. Most engines that stop running have simply run out of fuel, a problem easily avoided by proper planning and careful, constant monitoring. But despite my instructor’s chronic obsession with pulling the throttle, he never prepared me for the more likely kind of mechanical problem: a partial engine failure. In this scenario, only part of the engine stops producing power. A blocked fuel injector or a stuck valve, for instance, can rob you of 25 percent of your power in a typical four-cylinder engine.
You’ll know if this happens. It’s noisy and the airplane shakes. Your first thought will likely be that your engine is coming apart. But if the propeller is still spinning, something less sinister is likely afoot. First look at your engine temperatures, if you have any. A “dead” cylinder cools quickly. Work the throttle, and if the rhythm of the vibration increases and decreases with power, a cylinder has collapsed. You still have power to get to an airport. You can probably still even climb.
That said, it’s wise to make a decision quickly, because in rare cases, a partial failure could be the first sign of a total failure.
If the noise and vibration sounds irregular, like a skunk and a raccoon duking it out in a trash can—random, grinding, ripping—shut the engine down, pitch for best glide, pick a field… and remember your training.
But if the noise is steady, just stay steady—and plan to land on the nearest suitable runway.
