Bad for Aviation: Hand Propping Run Amuck

yeah that's right that long stretch of rope leads right here to the tail wheel mount on the cub and there's one other place it leaves too which is to our new avweb series called bad for aviation we're gonna look at how pilots do stupid stuff that cause accidents and incidents follow me watch your head on the strut see that cherokee over there it owes its very existence to that tail wheel tie down a few years ago i was starting this airplane by hand propping it which is the only way to start this particular cub it jumped the chalks and was boresighted on the cherokee over there if it had got loose i think it would have chewed it to bits and the whole megillah could have exploded so what saved it was that five dollar stretch of rope from ace hardware so in this series we're going to take a look at how you prevent that kind of stuff because in the end you lose control of your cub when you're propping it that's bad for aviation let's say for example it's airport day for the local scout troop and while they're chowing down on pancakes in the airport cafe before touring the ramp the young eagles get a surprise visit from a runaway cub or luskim or a malibu for pete's sake we can all agree this would be for aviation after all we don't want to scare the lads too early in their potential aviation careers or they won't be around long enough to buy pilot logo wear and combination flashlight fuel testers and that would be an incalculable human tragedy i wish i could say that such things are rare but they aren't really just on my airport alone there have been two in the past few years and the other day a champion got away from a friend of mine he was using a tail tie down but the rope broke and in this case had it not been for the fortuitous location of a drainage ditch this one could have made it into the runaway airplane hall of fame by either taking off or plowing into the italian food festival in the distance inadvisally the pilot pulled the engine through by hand because a starter malfunctioned he was trying to nudge the starter back into engagement no chocks no tie downs mags on throttle forward it could have been terrible for the foodies across the field but it definitely was that's pretty bad for aviation in my case i made a bad choice of chalks to paraphrase crocodile dundee that's not a chalk this is a chalk go ahead and laugh if you want to but this airplane's not getting away from me by running over the chocks the only reason i don't have bigger chocks is i can't lift bigger chocks the thing about hand propping even a small engine like this continental a65 is that well if it's not wild-ass crazy dangerous it's always risky if you can avoid it with an electric starter do that if your battery is dead grab a coffee and charge the battery save yourself the potential grief and if you're a cheap pilot bastard like me and you don't have a starter as a cub here surely does not then you got a hand prop and there are ways to reduce the risk of doing that first secure the airplane personally unless i just can't avoid it i never prop without both the tail tied down and the chocks period hard stop these chalks may be cartoon overkill but better that than this another runaway that happened last spring when mechanics started an unsecured cub it took off and flew for a mile and a half nobody hurt but one more cub turned into a yard sale and by the way when you tie the tail take up the slack in the rope so if it runs away it won't snap taut increasing the likelihood of parting as happened to my friend last week half inch rope is okay three quarter inch is better if you can't tie or chop the airplane for whatever reason the next best thing is to put someone in the cockpit to handle the throttle and hold the brakes and that ought to be a pilot not some clown you find wandering around the airport contact contact the fa recommended way of hand propping is to always have someone in the cockpit but any tail dragger pilot will tell you if you adhere to that you won't fly much sometimes if you want to fly you got to prop it without help even if i have someone in the cockpit i still tie it and i still chalk it i mean why not it takes two minutes and if those two minutes can prevent this from happening why wouldn't you do it and by the way if you're really worried about the airplane getting away one trick is to shut the fuel off before you crank it there'll be enough gas in the car bowl to start the engine and you can turn the fuel on after it fires with the fuel off the airplane won't get far and it certainly won't take off that would not however have helped the cherokee over there people who get injured in propping incidents are either run over by the airplane or they get some body part into the prop arc securing the airplane avoids the road kill staying out of the prop arc saves you from getting whacked this is the prop arc no matter how fast the prop is spinning if you stay out of the ark no harm will come to you it doesn't matter if you're in front of it behind it or to one side out of the ark is out of the ark and hear a word about magnetos i'm sure you know the good thing about magnetos is also the bad thing about magnetos they don't require any electricity to make spark energy sufficient to fire the plugs if they're spinning they can make spark what prevents them from doing that is this this is the p lead or primary lead it grounds the magneto coil and renders the mag inert that's what the magswitch does it connects the p-lead to ground but p-leads have been known to fail either by a wire break or a lug coming loose and that means the mag is hot and it can fire there are two mags on every engine and one failed p-lead is all it takes if you move the prop the engine might not start but it can fire enough to beam you so if you move the prop always stay out of the ark now where was i oh yeah impulse couplings many magnetos have a device called an impulse coupling it's a little spring-loaded doohickey that gives the magneto a little rotational acceleration to improve the spark when the engine is turning slowly which it is when you're hand propping now airplanes with electric starters usually have one impulse coupling sometimes two the a65 here can have one or two or none at all if it doesn't have one at all and you have to prop an airplane without an impulse coupling sucks to be you you can tell if it has an impulse coupling by rotating the prop out of the arc and that double click is the impulse coupling releasing the impulse coupling is energetic enough to provide enough spark to maybe fire a cylinder probably won't start but it can kick the prop and dope slap you straight to the er so stay out of the ark now where to stand when hand propping this gets a little religious some people are devoted to standing behind the prop some people swear by propping from the front of the airplane people who stand behind the prop often have colorful nicknames like lefty or stumpy and if they use their foot as a wheel chock they also tend to limp hey just kidding propping from the rear has one big advantage you have ready access to the throttle especially in a cub if the engine spins up more than you expect and believe me that happens you can readily reach in and chop it to get control of the airplane a little harder to do in a champ because the door's in the way so try to jam it open so you can get at it in a hurry if you have to also if you're propping from the rear and the airplane does get away it will tend to impale the hapless pilot on the strut which has the advantage of keeping the body near the wreckage and while that makes it easier for the first responders it's still ivy i think that's bad for aviation yeah that's bad for aviation oh and by the way one recommended technique in the cub is to hold on to the front of the door frame to keep yourself from slipping forward into the prop like this but you do need to watch your footing around the wheel and the shocks personally i like to prop from the front because well that's the way i learned to do it also if i have to run away i've got a clear field and i'm likely to be highly motivated but either way works if you're on floats rear propping is the only practical choice and unless you also own a boat with medical facilities on dry land just make sure the airplane is secured and that you stay out of the prop park if you pull it through with the switch off after you've primed and most of us do that do it the same way you would as if the mags were hot which they very well might be if a pea lead is loose this wouldn't be my favorite way of doing this on the prime blades pull it through like the engine is going to start the best advice is to place your fingers on the front of the prop and not wrap them around the blade this is because the prop can kick back when you're positioning it and although it might not injure you it sure as hell hurts ask me how i know and now the leg swing some people insist on it some people think it's kind of dumb because you're putting a body part into the prop arc maybe the leg swing is necessary for a big engine or radio but i hardly think you need it for a piddly little tail dragger but if you want to do the leg swing do the leg swing here's an example of both methods on a big rotary engine note that the guy who doesn't do the leg swing is the one who actually gets the engine started otherwise just grasp the prop hand on the front of the blade and step back decisively as you pull the blade through try not to lean too much toward the prop arc and if it's icy or you otherwise have poor footing well at least cold weather suppresses bleeding move the airplane to a better spot step to one side so you can clear the prop arc in two dimensions sideways and front ways some people like to step toward the right side of the airplane just to have better access to the throttle but i find that a little awkward if you've got someone in the cockpit make sure the brakes are set by pushing back on the prop before pulling it through and be clear about the throttle position and whether the mag switch is on or off i like to use the old school contact to confirm that the mags are hot if somehow against all the odds and the winds of fate you've managed to start the airplane without chopping yourself to bits or traumatizing the local scout troop for life the last area of risk is getting into the airplane once the engine is running some owners rig a glider or banner toe release so the tail can remain tied down while you climb in then just pop the release and you're on your way but it does leave the rope lying around on the ramp or on the hanger floor here's a clever nested chalk design that allows pulling the shocks from inside the airplane once it's started and you're strapped in you could easily make up a pair of these i just keep my 747 shocks in place and remove the left one first then the tail tie down and then the right shock when i'm ready to climb in i usually toss the chalk into the front seat or toss it through the open hanger door this is a little easier if i'm flying with someone who can hold the brakes for me so the message here is if you're propping keep the main thing the main thing stay out of the prop arc and remember if you're not both chalking the airplane and tying the tail down the next sound you hear might be the prop chewing through an unsuspecting cherokee and that would be really bad for aviation bravo i'm paul bertorelli thanks for watching [Music] one more thing before i go in this video i use a clip of brian barnett hand propping his j3 from the back notice before he does that he kind of hitches up his pants here it is again i recognize that body language because i do the same thing it's sort of the getting on to the game face am i ready to do this is the switch set where it's supposed to be how about the throttle i didn't forget the chalks or the tie down are my shoes tied so i won't slip and fall into the prop these things taken together prove a basic truth hand propping is a routine operation with acceptable risk but it is unforgiving of carelessness and shortcuts it can go from routine to catastrophe in a heartbeat if you don't know that you probably shouldn't be hand propping at all i'm just saying i do wish that guy would pull that prop back bonanza figures

Channel: AVweb

Views: 124,748

Rating: 4.9482379 out of 5

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Id: viiIBz1AEnQ

Length: 14min 51sec (891 seconds)

Published: Sat Sep 04 2021