After a pleasant but cold weekend in Boston, it was time to return to our home on an island off the coast of Cape Cod. After receiving a forecast for good VFR weather from Bridgeport Flight Service, I called the local FBO to have them preheat the engine on my 1974 Cessna Cardinal. When we arrived at Norwood Memorial Airport, it was 6 degrees Fahrenheit.
The aircraft passed my preflight inspection without any discrepancies. I reasoned that "pulling through" the propeller was unnecessary because the oil was warm from the preheat. I loaded my wife and child into the back seat of the airplane and climbed into the pilot's seat.
After running the checklist, I turned the key to "Start" but could only hear the starter whine. This had happened to me on other cold mornings, and I remembered my mechanic's suggestion that repositioning the propeller should correct the problem until it could be repaired permanently.
Most likely, there was either ice or residue built up on the pinion shaft, preventing it from engaging. I reasoned that if the propeller was moved to another position, the starter would operate properly.
I shut off the ignition and battery switches, got out of the airplane, and started turning the prop. On the third rotation, the engine started.
My first thoughts were of basic survival. I took a quick step backwards away from the propeller. It was turning at more than 1,500 rpm only six inches from my nose.
Realizing I had survived the encounter, I then focused my thoughts on protecting my family, secured by seat belts in the back of the now- moving airplane. Because of the slippery ramp conditions and the blast of the propeller, I could not reenter the cabin to apply the brakes. From the outside, the only thing I could do was try to block the wheels. But it was too late. The airplane was on its way.
In a few seconds, after traveling about 20 feet, it struck a parked airplane. Luckily, no one was hurt and both aircraft received only minor damage.
Apparently, a malfunctioning condensor in one of the magnetos still had enough life in it to render the mag "hot." After priming, there was also enough fuel in the cylinders to allow combustion. Since I trusted my ignition system, I had not adequately secured the aircraft. After an engine tear-down inspection and a new propeller, the Cardinal was able to fly again, thanks to an understanding insurance company.
After the incident, I discovered certain facts that had never been fully brought to my attention. Never in my eight years of flying had I been exposed to the proper precautions for hand propping, especially when the sole purpose of the rotation is not for an engine start. The small cautionary notations in owner's manuals are not enough.
Why wasn't it ever publicized that, if I turned the propeller opposite the direction of normal rotation, the magneto's impulse coupling would not generate a timed spark and the engine would not start? Although there is debate that reverse propping can damage vacuum pump vanes, one has to consider the value of his life relative to the cost of a vacuum pump vane.
I also found that there have been numerous recalls, service difficulty reports, and airworthiness directives issued concerning faulty ignition switches, internal magneto condensers, and P-lead wires that were often worn and not properly grounded. All of these items can contribute to a "hot mag" situation.
With multi-viscosity oils, "limbering" of the oil by rotating the propeller is now unnecessary. I have talked to several mechanics who believe hand rotation of the propeller in cold weather is without merit and should be completely discouraged. The only exception, of course, is if you have been properly trained to hand prop or you are flying a vintage airplane without a starter.
Many insurance companies will not insure losses for any accident claims arising from hand rotating your propeller — for any reason. I was lucky to have one that did. Even if you were following the recommended procedure and were not intentionally trying to start the aircraft, you may not be covered.
Whether you live in a cold climate or not, how many times have you manually rotated your prop after shutdown to get it out of the way so you could connect the towbar? This is a perfect scenario for an inadvertent engine start — the engine is still warm and, especially if you didn't shut the engine off by pulling the mixture to idle cutoff, residual fuel in the cylinders could still ignite.
I learned that about one-third of all inadvertent propeller starts result in serious injury or death to the unsuspecting pilot or ground personnel. Never again will I trust the ignition system to be fully functional and disconnected just because the key is in the "Off" position.
Paul B. Kovner is a private pilot with 725 hours of flight time, most of which is in his Cessna Cardinal. He lives on an island in New England.
"Never Again" is presented to enhance safety by providing a forum for pilots to learn from others' experiences. Manuscripts should be typewritten, double-spaced, and sent to: Editor, AOPA Pilot, 421 Aviation Way, Frederick, Maryland 21701.
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