When One Is Better Than Two

The pilot of a single-engine airplane and the pilot of a twin-engine airplane both prepare to takeoff on parallel runways. They begin their takeoff runs together; they break ground at the same time. Then, just after lift-off each pilot experiences the loss of one engine. At this moment, which pilot is in greater danger?

Common sense would say that the twin-engine pilot is in less danger, because after all, the pilot of the twin-engine airplane has an extra engine for just such occasions. But this statement is false. Believe it or not, it is the single-engine pilot who, having lost the use of his only engine and now has no power at all, is better off.

If you have only one engine and that engine fails, the pilot does not have many options. More important, the pilot is not really faced with any difficult choices. The only thing the pilot can do, is keep the wings level and land straight ahead. Hopefully the pilot will find something level to land on straight ahead — like the remaining runway, or the clear zone beyond the runway (sidestep the approach lights, if possible). But the point is that the single-engine pilot wastes no time figuring out options. The single-engine pilot has only one option: Land straight ahead.

The twin-engine pilot is in greater danger in two ways. One is caused by aircraft design, while the other has much more to do with the pilot…

  1. On conventional wing-mounted twin-engine airplanes, the loss of one engine sets in motion some possibly uncontrollable forces on the airplane. How it works: With both engines running the airplane is pulled through the air equally from both sides. But when one engine quits, the engine that is still operating continues to pull forward, but not through the center of the airplane.Essentially the operating engine — and its side of the airplane — tries to out run the non-operating engine and its side of the airplane. The airplane will sway in the direction of the dead engine. It would be like letting the right wheels of your car slip off the shoulder of a road into loose sand. The car would sway toward the side that has less traction/less thrust. This sway or yaw, must be controlled with rudder immediately or else the airplane will be flung like a Frisbee. The single-engine pilot, has no need to worry about all this and would probably be back safely on the ground by now.
  2. The twin-engine pilot is in greater danger because of the twin-engine mindset. The pilot might, in that blur of a moment when one engine quits, have the crazy notion that they can use the operating engine to climb out to safety. Now, there are some twin-engine airplanes that can climb out using only one engine, but by and large the airplanes that are used for multiengine training cannot.

If the pilot erroneously believes that the good engine will save him, when in fact the good engine is not capable of saving him, then valuable time can be lost as the pilot deliberates a decision that physics has already made. During the few moments when the pilot is hopelessly attempting to coax the airplane to fly, the airspeed will diminish, the rudder will lose its ability to counteract the yawing motion provided by the good engine, and the airplane will soon be out of control. It will flip over and crash.

The single-engine pilot has no choices and therefore wastes no time landing straight ahead. The twin-engine pilot also has no choices, but they might waste precious time before realizing that fact. Trying to force an airplane to fly when it is physically not capable of flight can be fatal. So what should twin-engine pilots do if they lose one engine just after takeoff? Ironically they should do what single-engine pilots do: Land straight ahead with no power. Cut the power to the good engine and land straight ahead on whatever is available.

It’s better to land straight ahead under control and with wheels under you, than to hit the ground out of control and on your back.

Twin-engine airplanes do have advantages over single-engine airplane — like when flying at night, or flying over mountains, or flying over water. In these situations however, the airplane has altitude and speed. But if I ever have an engine failure just after takeoff — where I’m slow and close to the ground — I hope I’m in a single-engine airplane!