Never Again

Prop bites

April 1, 2005

As I pulled the propeller blade down, a cylinder fired and sent the propeller spinning. It happened in a split second and nothing seemed wrong until the engine fired. I never imagined I would have this story to tell.

I have been involved with airplanes and aviation for most of my 54 years. Starting when I was very young my dad took me flying and taught me the basics of aviation. One of my earliest memories about airplanes is my dad explaining the dangers of propellers. "Don't go close enough to a propeller for it to hit you if the engine starts unexpectedly" and "Don't touch or move a propeller unless you have the proper training and use the proper procedure" — that's what I remember.

We often rented an Aeronca Champ at Saginaw Airport, just north of Fort Worth, Texas. (The airport has since been swallowed up by development in the area.) On those first flights I started learning about propeller procedures. "Brakes set, mixture rich, mag switch off," then our helper outside would step up to the propeller and pull it through a few times and step back. "Mag switch on, contact!" Only then, our helper stepped up again, pushed backward on the prop to check that the brakes were set, then gave the prop a good swing, and the engine came to life. A wave of thanks and we were off.

After U.S. Air Force pilot training and many different airplanes, I find myself with almost 6,000 flight hours; I've developed a strong attraction to older airplanes and enjoy learning, as well as teaching, the techniques and procedures required to operate and fly them.

Today my pride and joy is a 1946 Fairchild 24 with a 200-horsepower Ranger engine. The Fairchild 24 and its Ranger engine were mainstays of general aviation in the 1930s and went on to help fight World War II in the 1940s.

The Ranger is an in-line six-cylinder engine, built with the cylinders inverted, pointing down instead of up, so propellers mounted on the crankshaft could have plenty of ground clearance and not have the cylinders block the pilot's view. However, upside-down cylinders, either on radials or in-line engines, can collect oil in the combustion chamber after the engine is shut down. If too much oil finds its way into the combustion chamber when the engine is starting it can produce a hydraulic lock during the compression stroke.

This situation results in lots of bending and breaking of engine parts. Pilots of older-vintage airplanes avoid this problem by pulling the propeller through before starting. The idea is to turn the engine through at least one compression stroke for each cylinder to clear any excess oil.

Older airplanes also often have wood propellers, as is the case with my Fairchild. Wood propellers should be stored in the horizontal position to prevent different amounts of moisture from accumulating in each blade and causing an out-of-balance condition. This requirement usually causes the pilot to pull the engine through one or two compression strokes after shutting down. These characteristics of older airplanes place the pilot in frequent contact with the propeller.

Over the years, I got the proper training and always include some specific procedures in my flying to ensure propeller safety, especially in the Fairchild.

So on a beautiful July morning I had been out enjoying some Fairchild flying and beautiful Colorado mountain scenery. Back at the fuel pumps at the airpark near Erie, Colorado, where I live, a friend came up to chastise me for having too much fun without him.

After taxiing from the fuel pumps, I swung the Fairchild into position in front of my hangar, checked the magneto grounding, then pulled the mixture control to full lean to kill the engine. As the propeller came to a stop I turned the magneto and master switches off and shut off the fuel valves. I got out, opened the hangar, pushed the airplane in, and chocked it. I spent some time cleaning oil and bugs off the airplane. After finishing up I was in front of the airplane and reached up for the propeller, thinking, "I'll pull it through to clear any oil that is starting to accumulate and to straighten the prop."

As I pulled the propeller blade down, a cylinder fired and sent the propeller spinning. Before I knew what had happened, it hit the back of my right hand and the fingers of my left hand. After hurrying to the sink in the hangar and wrapping some wet towels around my right hand, I headed back to the airplane. I could not understand how the engine fired after I had just checked the magneto grounding before shutdown. Upon reaching the cabin door I immediately saw the problem. The key was still in the magneto switch and the switch was on the right magneto, the position next to Off.

My hands were hurting and swelling rapidly because of broken and shattered bones. There was also a cut on the back of my right hand that would require three stitches. Repairing the demolished bones would require three and a half hours of surgery and more titanium plates, pins, and screws than I want to count. All the medical professionals commented about how lucky I was that my injuries were so minor. Propeller injuries are usually much worse.

What went wrong? Why didn't I get the magneto switch turned all the way off and the key removed? I cannot remember anything unusual that distracted me during the shutdown. Something clearly did, and it caused me to leave the magneto switch in the Right position and the key in the switch. Why did I move the propeller without checking the magneto switch? I believe the answer is that I was certain I had completed the shutdown as usual. In my mind the switch was off and the key was in the airplane's side pocket. As I reached for the propeller, it did not even occur to me to go check!

Distraction, complacency, overconfidence, assumption — all of these must have been at play and resulted in failure to complete or use proper procedures, twice! First, not completing the shutdown procedure. Second, not checking the magneto switch before moving the propeller. It seems so clear looking back, but it happened in a split second and nothing seemed wrong until the engine fired.

What went right? I only had a badly broken right hand and a broken little finger on my left hand. The emergency room doctors and nurses told me they normally see severe head or upper-body injuries from propeller accidents. This kind of accident can easily be fatal. This time, the engine did not have enough fuel available to actually start running. The airplane was chocked and did not move toward me.

Odds are that I will never touch a propeller again without checking the magneto switch, no matter how recently I have turned it off. Beyond the specifics of propellers and magneto switches, this accident has underscored for me the importance of checklist procedures, and repeated verification of them, to guard against deletions because of unnoticed distractions. It also points out to me how easy it is to make an assumption, and act on it, without realizing an assumption is being made.


Chuck Clemen, AOPA 432796, is a commercial pilot and flight instructor with nearly 6,000 hours. Along with the Fairchild, he owns a 1994 Maule MX-7-160, and a 1958 Piper Pacer project.


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