Retired airline captain Barry Schiff has been flying and instructing for nearly 50 years.
Every once in a while we read about a hapless pilot who hand-props an airplane without someone in the cockpit. The machine has its way and powers itself into other aircraft. I recall at least one instance when an empty airplane actually took off and flew aimlessly for quite a while before crashing.
There was a time when electrical starters were the exception and most airplanes had to be started by hand. Even following World War II most small trainers — such as Aeronca Champs and Piper Cubs — had to be hand-propped.
Today, most aircraft have electrical starters, and the only time a pilot needs to start an engine by hand is when the battery is dead. Finding a line person willing to prop an engine is like finding free avgas. They either don't know how or the FBO for whom they work prohibits hand-propping because of insurance restrictions.
What many pilots do not realize, however, is that if the battery is really dead and the airplane has an alternator, hand-propping won't do any good. Oh yes, the engine can be started, but nothing electrical will operate. This is because an alternator cannot generate electrical power without some current from the battery. This points out an advantage of a generator, which can develop electrical power even when the battery is completely dead.
Never attempt to prop an engine unless you have first been instructed by someone who knows how to do it safely and understands the hazards involved. The first thing you will be taught is to ensure that you are standing on firm ground. Avoid gravel or other surfaces that might cause you to lose footing. You also will be taught the proper way to lay the palm of your hand on the face of the blade with the fingertips barely curling over the trailing edge. Never grip the blade unless you are willing to sacrifice fingers or a hand to the cause.
You also will learn the proper terminology for communicating with the person in the cockpit. This includes Switches off! (ignition off), Contact! (ignition on), and so forth. (Contact! should not be called until a blade has been moved to the 10:30 position with the switches off and it is immediately ready to move through a compression stroke.) Never trust that the pilot has set the brakes even when he says they are set. Push on the spinner to ensure that the airplane doesn't move.
As a pilot develops proficiency in hand-propping, he will learn to avoid aircraft with high-compression engines as well as those with three- and four-blade propellers. These are more difficult and dangerous than those with low-compression engines and two-blade propellers.
A pilot should not prop an engine unless it is at a safe height. If the engine is too close to the ground or too high above it, propping the engine requires leaning forward into the propeller disk or stretching awkwardly to reach a high blade, either of which makes it easier to lose balance and fall into a whirling propeller.
Postwar taildragger trainers have their propellers at just about the ideal height. But the same-size airplane with a nosewheel lowers the engine, which makes propping more difficult. An Ercoupe, for example, is easy to prop except that it is too low for someone tall.
When I was a 16-year-old lineboy, the pilot of an Aero Commander with a dead battery asked me to prop one of the twin's lofty, high-compression engines. It was not appealing, but I caved in when he offered $5 for each blade that I pulled through a compression stroke (ignition On). That plus youthful foolishness and conviction of immortality swayed me. Color me stupid. It wasn't worth the $55 I earned for propping that engine, but my, that was a lot of money in those days.
For those who know how to prop an airplane without endangering themselves, there is a relatively safe way to do it without anyone in the cockpit — a procedure that I used successfully when I owned an Aeronca Champ.
Before starting, ensure that the airplane is tied down and chocked. To prevent the throttle from vibrating open after engine start, restrain the throttle in the fully closed position with a bungee cord secured to some structural member in the cabin. Then prime the engine as necessary, turn off the fuel valve, turn on the ignition, and go for it. After confirming that the engine is idling satisfactorily and won't go anywhere, untie the airplane, remove the left chock, climb into the cockpit, and remove the right chock using a cord leading from it to the cockpit. Finally, return the fuel valve to the On position (before the engine dies of fuel starvation) and remove the bungee cord from the throttle.
Seaplane pilots, of course, cannot prop an engine from in front of the aircraft unless they can stand on water. (I have met a few pilots who believe they can.) Instead, the pilot stands on the right float, flicks the prop downward from behind, and clambers into the cockpit when the engine starts.
One instructor refers to the segment of space between one propeller blade and another as an "arc of death." Stay away from it unless you know what you're doing, and never stick anything in there that you can't afford to lose.
Visit the author's Web site ( www.barryschiff.com).
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