What if?

I shoved the thrust levers about three-fourths forward and called for our flight engineer, John, to “trim throttles.” He further advanced the thrust levers and made fine adjustments until each of the three engines on our Lockheed L–1011 TriStar produced the same amount of thrust.

The center engine was running a little hot, so I asked John to pull it back slightly. Through the corner of my eye, I could see he was retarding the throttle more than I would have expected.

“Rotate!” I raised the nose in response and had the TriStar poised for flight on its hind legs when I noticed that John had pulled the throttle fully aft, yet the engine was still developing full power and running hot.

“Nothing I can do with it, Barry. We’ve lost control of Number Two.” John demonstrated by moving the throttle fore and aft with no change in power.

“That’s a new wrinkle,” I replied as we began climbing to our assigned altitude. The first officer said correctly that we had to treat this like an engine failure.Virtually everything in an airplane has the potential to fail and at some point, probably will.

We advised ATC of our need to return to Newark as John pulled out the engine failure checklist. I turned off the start switch, which immediately deprived its engine of fuel. We were safely on the ground 15 minutes later.

Although this was an unusual event, something similar can happen in a lightplane when a throttle jams. If it freezes in the idle position or when developing insufficient power to maintain altitude, there is no option in a single other than to make a forced landing. But how would you handle the situation if the throttle jams and engine control were lost while developing cruise or climb power? Descending, approaching, and landing safely with excess power could be challenging. The only way to handle the problem would be to shut down the engine with the thought of cycling power on and off as needed.

Some might be surprised and amused to learn that this was the way pioneer pilots operated their rotary engines. Such an engine rotates about a fixed crankshaft attached firmly to the airplane. (Engine rotation cools the cylinders.) The pilot used a “burp” switch on his control stick to turn the ignition on and off. There was no in-between. It was either full power or none.

Although a pilot with a jammed throttle also can vary power from full to none by cycling the magnetos on and off, it probably would be better to use the mixture control. When the mags are turned off, the engine continues to inhale a fuel-air mixture that could contaminate and foul the spark plugs, which could interfere with power restoration. Using the mixture control to modulate power is effective if the propeller continues to windmill, which it should if airspeed is maintained at or above the best glide speed.

During my decades of flying, I have observed that virtually everything in an airplane has the potential to fail and at some point, probably will.

In 1958, I was flying a cattle buyer from Los Angeles to a feed lot near Gilroy, California, in a Ryan Navion. It was a cold night, and my passenger asked me to turn up the cabin heat. I pulled out the knob and waited for warm air to flood the cockpit, but there was none. I pulled the knob farther, and it came loose in my hand. There would be no warmth on that wintry night. I should have known better, but we opted to continue even as the cabin became increasingly frigid, almost to the point of being hazardous.

Along similar lines, have you ever opened an air vent and discovered that you were later unable to close it? It happens.

While flying a Beechcraft Bonanza from Reno, Nevada, to Albuquerque, New Mexico, I began to switch fuel tanks. The valve was somewhat stiff, so I muscled it in the desired direction, which is when the handle broke off in my hand. Fortunately, there was a pair of pliers in the glove compartment that I could use to wrench the valve into position. To this day, I never plan to switch tanks unless relatively close to an airport.

Fortunately, most gadgets in a modern airplane are extraordinarily reliable, but like all devices, they can fail and create consequences you might not have considered. On the next rainy day, crawl into a cockpit and play What if? Ask yourself what you would do if this control or that switch were to fail. It can be an enlightening exercise in preparedness.

www.BarrySchiff.com