You don’t hear about people hand-propping planes very much any more. While there are still a good number of planes without electric starters out there, the pilots that fly (and hand start them) are generally a well-trained and cautious bunch, and don’t generally get into trouble.
THAT IS WHERE OUR STORY STARTS, KIND OF. In this case, we have a pilot of a large-bore, 300 horsepower Bonanza, who decided to pull the engine through by hand before starting it. His logic made sense at the time: the plane hadn’t been run in 30 days, and he wanted to pull the engine through to get the oil moving. After checking to make sure the engine was safe by looking at the start switch, he grabbed one of the blades on the 3-blade prop with one hand, and tried to pull it through.
TRIED is the functional word here – the engine wasn’t seized, but had really good compression. Our pilot tugged at the prop once, twice, three times, and couldn’t get it to move. With his bare hands, he moved outward on the prop blade to get more leverage, gave the prop blade a good heave, and was successful.
“WHOOSH” went the prop blade, now over the hump of the compression stroke, the piston drove the blade downwards, right into the path of the pilot’s other hand, which had been thrust into the disc of the prop by the effort of pulling the prop through! “SMACK” went the prop, right into the pilot’s outreached hand!
The pilot’s left hand got smacked pretty good by the propeller, which left a nice hash mark across the pilot’s index finger and knuckle. Some blood was drawn by the abrasion caused by the prop, and the pilot’s hand eventually turned several interesting colors to remind him of the folly of this effort. While no hospitalization was required and the bones in the pilot’s hand weren’t broken in this chance encounter, all it would have taken is having the hand move a little more, or the prop move a little faster, and the results could have been quite a bit different. Fortunately for the pilot, he had a recent Tetanus shot, or he would have had to get one of those for his efforts as well.
ENGINES AND PROPS ARE DANGEROUS – RUNNING OR NOT. Our pilot made several errors in judgment that led to this event:
1. The pilot was distracted talking to an instructor at the time this happened. He wasn’t focused on the task at hand, or the risk associated with it.
2. How often had the pilot done this? Unlike pilots of planes without starters, this was an infrequent event, which means his skill levels were probably minimal at best.
3. The pilot only used one hand to pull the prop through. His other hand had his flight kit in it, but if it hadn’t been occupied, it wouldn’t have swung into the area of the prop to be hit.
4. The pilot had gloves in his pockets, but didn’t use them to protect his hands. While the gloves were winter leather gloves, the damage the pilot received to his hands would have been less had he been wearing his gloves.
THE BOTTOM LINE: Treating every propeller as if it were live makes good sense. When you consider the energy behind the compression stroke of the engine, it doesn’t take a rocket scientist to know that the force generated will have an adverse impact if it comes in contact with your body. Learn from this painful lesson, and use care in pulling your propeller through. Trust us: you won’t miss the pain or the rehabilitation time, but you WILL miss the flying time that you could lose as a result of this type of contact.