Why We Follow the Rules When Hand-Propping an Aircraft

By Mike Davenport, EAA 89102, Langley, British Columbia

I have hand-propped many aircraft over the years. There have been Kinners, Franklins, Lycomings, and Continentals, and while some were easier than others, there was never a moment when I didn’t approach the task with caution. Had I not, a recent effort could have turned out very badly.

We pulled the aircraft out of the hangar to taxi it to the pumps and top off the two tanks after some maintenance. We had been doing some repair work on the fuel system that required the tanks to be drained. The gauge on the header tank is simplicity personified: a bent wire in a cork. How much gas you have is indicated by the position of the bend in the wire. If it is up high, the tank is likely full. Conversely, if little wire is showing, you should either have a gas pump in sight or fuel in the wing tank. But I digress.

The owner as per usual got in the front seat, and together, we went through the starting ritual.

The author hand propping well clear of the blades

The calls were routine: Fuel is on, switches say off, and two shots of prime while I pull the prop through six blades. Then he called brakes set, throttle set, and contact. At that point I repeated each call and got a nod in response. As I swung the prop I stepped back each time, keeping all of my personal bits and pieces well clear.

This time, however, the engine showed no sign of wanting to start, so we assumed it was flooded as gas was leaking from the carb. I confirmed that the switches were off and then pulled the prop backward several times to clear the flooding. Once more we went through the familiar starting ritual, and it started on the second blade.

I climbed into the back seat while he called the tower and got permission to taxi to the pumps. All good but … when we got there, he turned the mags off and nothing happened. Well, actually something did; the engine kept on running! The switch position had no effect. Since this was clearly not a good thing, we made a quick call to tower and got permission to taxi back to the hangar. Once there we messed with the switches and throttle to no avail. The engine just kept on running. This obviously was not acceptable, so he turned off the fuel and eventually it quit when it consumed all the gas in the system.

The cause of all this inconvenience was a broken wire that allowed the mags to remain “hot.”

I did say inconvenience, didn’t I? But think of the worst case. If I hadn’t used the proper technique and it had started on one of the dozen or so blades I had pulled, I could have been seriously injured or, worse yet, my friends and family could have been planning a memorial. If you have to hand-prop an airplane, please get instruction on how to do it properly, and also treat every propeller you touch as if it is “hot.”

Post Comments