I get a certain perverse pleasure out of fishing for stupidity and not to make light of my fellow aviators’ misfortunes, the Grand Banks of stupidity is found in the NTSB accident database. Here, you will find a vast and ever varied trove of trained, government-certified airmen enlisting the aid of perfectly serviceable airplanes to commit appalling acts of incompetence.
Some of these are truly 10-9 random events that no one could have avoided, but just as many are palm-slap-to-forehead triple gainers into an empty pool. That suggests there really ought to be a check box on the NTSB 830 form that says “What The ^%& Was I Thinking?” The honest and self-aware among us should admit that in a long flying career, we’ve come perilously close to our own entry in the Darwin sweepstakes once or twice. Maybe more. I certainly know I have and, unfortunately, quite recently. And not for a reason I would have ever imagined possible.On any metric of stupid acts, the guys who let an airplane they’re propping get away from them are your 90thpercentile in brain numbness. How hard is it to keep this from happening, right? Yet it happened to me and I’m still not certain why. On to the gory details.
Propping is an act that tempts fate in the way that dancing on thin ice or squirting lighter fluid on smoldering charcoal does. I have a love-hate relationship with the process. I love it because it means I’m about to fly an airplane reduced to its most basic elements; no farting around with master switches, batteries, lights, glass gizmos and all the other peripherals that don’t relate to just flying. I hate it because as much as I realize the previous sentence is utter bulls&^t, no matter how careful you are, propping is flat out dangerous for reasons I needn’t enumerate.
I am, therefore, obsessively careful when propping. I double chock the wheels, tie down the tail and I’m acutely aware of throttle and switch position before I touch the prop. And as a crusty old instructor whose name I have forgotten taught me 40 years ago, I always assume the mags are hot. And I never, ever pull the prop through to clear the cylinders with the throttle wide open, whether the switch is hot or off, whether it’s tied down or with someone in the airplane. I’d rather let it sit until the next day than take that risk. Last, if I have a choice, I don’t use the self-serve pumps so I can avoid at least one start cycle. I call the fuel truck or use the gas cans in the hangar. Like an extra $1.60 on a fill-up isn’t worth avoiding propping a hot engine?
Yet when you fly an old airplane like our Cub and you fly alone, you make certain compromises. You can’t, contrary to what’s wisely recommended, have an experienced hand in the cockpit to handle the switch and throttle. That means you have to reposition the prop with the mags hot between swings or else do a hell of a lot of walking. No one I know does that. Where to stand when propping is negotiable. I like to stand in front because that’s what I learned and my swing through ends with a vigorous backwards step. Some people like to prop from the rear, standing between the strut and prop; others stand to one side. Whatever works. It’s a comfort-level thing that I don’t think matters much in the absolute.
All airplanes have a propping personality of sorts and all are probably different. Our Cub, with a 75-hp Continental conversion, likes two shots of prime and three pull throughs with the switch off. Then it will start on the second or third blade when the switch goes hot. A cracked throttle gives it a brisk enough idle to run with a will. But the day it got away, it didn’t behave that way. Ten blades into the effort, not even a pop. Odd.
Switch off, another shot of prime and a couple of pull throughs. Switch back on, throttle cracked and it fired on the first blade. Then came the surprise. After a shaking, snorting idle, it roared to, if not full power, pretty close to it. No risk to me, I was 10 feet away and to one side. But the Cub jumped the chocks and headed straight for the shade hangars across the alley for a line of new sun hangars. Would have made it, too, but the tail tie did its job and stopped it cold, but not without pulling the hangar door off its track, which is how the tie was secured. By the time I got around to snap the throttle back to idle, it was already at near idle. WTF? (And by the way, I know the trick of turning the fuel off for starting; wouldn’t have made a difference here.)
I ran this scenario by a couple of friends, both of whom suggested the extra shot of prime may have caused this. But that’s not possible. Engines need fuel and air to generate power and one without the other generates nothing. In other words, to roar up to near full power, the throttle had to be open or at least more than cracked. How it got that way, I haven’t a clue. Just as I always do, after the prime, I pushed it back to the closed stop, then cracked it off the stop. I know I didn’t intentionally advance the throttle beyond that, but it sure as hell got advanced somehow. I was the only mook on the ramp.
The reason it jumped the chocks is that we have several pairs; a jet-sized pair normally used for starting and a smaller set that goes in the baggage compartment. That set was missing, so I used another small set in the hangar because I knew I’d need them for starting at the field where I was planning some photography and wanted to take them with me. Those chocks, clearly too small, went to the scrap heap and I replaced them with a pair suitable for securing an F-18 at takeoff thrust. These consume the entire baggage compartment, but desperate times call for desperate measures. Also, returning home with unsoiled underwear has a price that might include no room in your already minimal baggage compartment.
Other than the bigger chocks, I haven’t changed anything about how I prop the airplane much. I can’t be any more careful with the throttle and switch because prior to this fiasco, I was being as consciously careful as I knew how. One small change, I guess. I discovered that the engine will start with the throttle fully closed. It kicks over in a clanky idle that keeps the impulse coupling banging away, but it runs and it’s altogether less frantic.
Summing all this up, more good than bad came of it. We got a set of ass-kicking chocks and the hangar door, which used to be slightly off kilter and stiff to operate, now works better than ever. Best of all, thanks to a presciently placed length of -inch Dacron, I avoided becoming just another hapless mullet in the NTSB’s remorseless list of idiocy. Close may count only in horseshoes and hand grenades, but I’m gonna go with this: It counts in propping, too.