SPORT AVIATION Mistake

[1600vw]

Don't point that thing at me! And you'd not be welcome on my range with that attitude. The NRA's three safety rules are:

1. ALWAYS keep the gun pointed in a safe direction.
2. ALWAYS keep your finger off the trigger until ready to shoot.
3. ALWAYS keep the gun unloaded until ready to use.

I bring this up because it's also a good attitude with that meat cleaver on an aircraft. Any one of them can keep you safe IF there are NO mistakes made by imperfect humans, but we all make mistakes at one time or another, no matter how hard we try, since we are not perfect. But if you follow #1, a mistake with #2 or #3 can't hurt you. You actually have three practices that almost completely eliminate the chance of a serious mistake. But they ALL take practice, especially the first one. For some things it might not matter, but with the potential consequences of a mistake in this area the belt and suspenders approach can be a life saver.

The same is true of avoiding the prop arc. Sure, there are certain situations where you might not be able to avoid that prop arc, but they should be rare, and faithfully practicing that avoidance should (hopefully) come to make you uncomfortable getting into that arc. This is NOT saying that the other practices shouldn't be followed, just that staying out of that arc is akin to rule #1 above.

So you never look down the barrel of a gun when you are cleaning it? Its broken down. You do not get it.

Do not use a switch to kill the engine and no way to make a mistake. Why just why would you shut off your airplane engine with a switch? No good practice at all. Make the engine die and it will not bit you or anyone else who might happen to walk up and lean on said prop. I go into my hangar all the time and find the prop moved. Now do not say people should not be moving my prop. Its being done by an A&P who keeps moving things around. Then leaves my wooden prop in the 12-6 position but this is another story.

Tony

[cub builder]

Tony, you have some misconceptions about engines not firing after starving them for fuel. There are residual vapors left in the carb that accumulate in the intake.

Shut down a carburated Lycoming or Continental some time with the mixture control, let it sit for about 10 or 15 minutes, then pull the prop through with a hot mag. It will usually fire. Yep. You can do the same after running the float bowl empty. Residual vapor accumulating in the intake is enough to make it fire. Never trust an engine to not fire.

As an A&P, I spend a lot of time working within the prop arc. That's why the spark plugs are one of the first things to come off the engine at inspection and one of the last things to go back in. Always respect the prop as potentially hot, but there are safe ways to work within the prop arc if necessary.

You read about the A&Ps that put the plugs back in. Those are the guys that get whacked by a prop on a "cold" engine with mags and fuel off.

-Cub Builder

[Bob Dingley]

Why I say kill your engine by starving it for fuel. This would have never happened had the pilot done this. This story makes a good point for this. Would you leave a bullet in the camber. you are doing this when you leave a fuel air mixture in the cylinder ready to fire. It's a loaded gun.

Tony

I get it Tony. It could have happened like this: Someone may have flooded the Cessna engine and flattened the battery. Re-hangared it with fuel in the jugs. No way to do a checklist shutdown. Ever fly with a club? Some one comes along and moves the prop. This is where we find out if it also has a bad P-lead.
Did I mentioned that I was military pilot at one time? Some days, I flew both a T-41 and a club C-172. Same animal. Every military recip, including the T-41 has an item in the runup C/L (after"mag check" and "idle check") called "grounding check". The C-172 does not, This is where you find the bad P-lead. I like to do grounding checks in everything I fly whether it has a star painted on the side or an N number.
For a time I flew a military type that had an O-540 Lyc and no mixture control. Shutdown C/L called for "Throttle 1500 RPM, FUEL VALVE OFF. Mags off after engine stops". No danger of prop strikes. It was a helo with a clutch.


Bob

[lnuss]

So you never look down the barrel of a gun when you are cleaning it? Its broken down. You do not get it.

Note that cleaning the gun isn't normally done on a live range, though there are exceptions, but those rules are for handling a gun anytime, range or not. And that "I can point it anywhere because it's unloaded" attitude isn't allowed on the ranges where I work. You're trying to justify avoiding those rules, or so it appears, but I don't know why.

I normally don't look down the barrel even when cleaning, unless it needs inspecting, then it's only when the barrel is removed from the action (or lock, in muzzleloaders) and magazine. Even when it's broken down, I do my best to avoid the barrel pointing at anyone, as much for developing the habit, as for anything. You don't seem to get the concept of belt and suspenders or, in this case, developing safe habits, as well as setting an example for others around you. And you certainly don't look down the barrel of a muzzleloader after it's been fired, even though you're sure it's empty -- there's still danger.

Do not use a switch to kill the engine and no way to make a mistake. Why just why would you shut off your airplane engine with a switch? No good practice at all. Make the engine die and it will not bit you or anyone else who might happen to walk up and lean on said prop. I go into my hangar all the time and find the prop moved. Now do not say people should not be moving my prop. Its being done by an A&P who keeps moving things around. Then leaves my wooden prop in the 12-6 position but this is another story.

Tony

I didn't mention anything about a switch, nor did I say I would shut off my airplane with a switch (though I might in a Cub, or the Chief I learned in -- no choice). Don't go reading things into my words that I didn't put there. I normally pull the mixture. But it's still possible for the engine to fire after shutdown, even if it's not able to keep running, and it only takes one or two cylinders to fire to potentially cause injury.

It's the same principle as closing a drawer so people won't trip over it, and not leaving a drinking glass near the edge of the kitchen counter, since when I walk by my elbow might bump it -- I don't need broken glass on the floor, nor a spilled drink. It's about prevention, Tony, not macho pride in always being careful. Perhaps you are sufficiently perfect that you never make a mistake, but I'm not, nor are most people. So I try to compensate by eliminating the potential for problems when I can recognize it, then still being as careful as I know how to be -- belt and suspenders.

I still avoid that prop arc to the extent possible, even with a cold engine that has mags off, that was tested for grounding just before shutdown, and has mixture lean and fuel shut off. There is still a residual danger, though it's unlikely to be a problem under those conditions, and good habits take time to develop, but not much time to break.

Bye...

[rwanttaja]

The whole point, I think, is that a prop...like a gun...should never be treated casually. Always handle both as if the worst-case event could happen. On cold days, I turn the prop over (backwards) by hand to loosen it up a bit; I have to move the prop to remove the cowling from my airplane. In all cases, I keep as much of my body out of the danger zone as possible.

Bill's objection, and my agrement with it, is that taking a photo with the airplane *is* a casual event. No reason to touch the prop or get in the arc.

Years ago, I came out to fly, and a buddy's T-18 was parked on the taxiway outside his open hangar ready to go. I figured he was out visiting the sani-can, and took off for a short flight. When I came back, it was still there. I called my buddy's home number, and he WAS there...and hadn't been to the airport that day.

Someone had tried to steal his airplane. Fortunately, his master switch was in an odd position, and they probably were stopped when they didn't find it. But it's not beyond the realm of possibility that they'd got the engine primed and ready to start. The mags were toggle switches, didn't need a key to start. If they'd wanted to cover their tracks, they could have tucked the airplane back in the hangar with no one the wiser...and the engine ready to go. As it was, the T-18 shared the hangar with an Ercoupe, and it took some trickery to fit them back together (they'd actually dropped the Ercoupe onto the T-18's wing in getting the homebuilt out, its tiedown ring gouging the skin).

In any case, this could have been a case of an airplane ready to go, with no (legitimate) person the wiser.

(The full story...which is even weirder...can be found at http://www.bowersflybaby.com/stories/witch.htm)

Extremely low probability, yes. But not messing with the prop unless necessary is a good policy....

Ron Wanttaja

[1600vw]

The whole point, I think, is that a prop...like a gun...should never be treated casually. Always handle both as if the worst-case event could happen. On cold days, I turn the prop over (backwards) by hand to loosen it up a bit; I have to move the prop to remove the cowling from my airplane. In all cases, I keep as much of my body out of the danger zone as possible.

Bill's objection, and my agrement with it, is that taking a photo with the airplane *is* a casual event. No reason to touch the prop or get in the arc.

Years ago, I came out to fly, and a buddy's T-18 was parked on the taxiway outside his open hangar ready to go. I figured he was out visiting the sani-can, and took off for a short flight. When I came back, it was still there. I called my buddy's home number, and he WAS there...and hadn't been to the airport that day.

Someone had tried to steal his airplane. Fortunately, his master switch was in an odd position, and they probably were stopped when they didn't find it. But it's not beyond the realm of possibility that they'd got the engine primed and ready to start. The mags were toggle switches, didn't need a key to start. If they'd wanted to cover their tracks, they could have tucked the airplane back in the hangar with no one the wiser...and the engine ready to go. As it was, the T-18 shared the hangar with an Ercoupe, and it took some trickery to fit them back together (they'd actually dropped the Ercoupe onto the T-18's wing in getting the homebuilt out, its tiedown ring gouging the skin).

In any case, this could have been a case of an airplane ready to go, with no (legitimate) person the wiser.

(The full story...which is even weirder...can be found at http://www.bowersflybaby.com/stories/witch.htm)

Extremely low probability, yes. But not messing with the prop unless necessary is a good policy....

Ron Wanttaja

I agree with everything you state. I say it's good policy to not leave your engine ready to run. All the stories I hear from not only engines firing from bumping the prop. But also from people who take off with the fuel off. Seems like if you kill your engine from lack of fuel, kinda hard to start said engine with the fuel off.

So the very first thing I do in order to start my engine is grabbing the fuel shut off valve and turning it on. If I find it on I know someone has tampered with my airplane. I then must move my mixture to rich. I must close the choke and light the mag. Check throttle to make sure she is at idle.

It then takes 3 complete turns of the prop before it will fire.

No way to ever leave the ground with the fuel valve closed nor anyway for the engine to fire as I check the oil or the gascollator, or any other thing I want to do on my pre-flight walk-a-round.

Seems like a safe way to fly to me.

Goodbye....

Tony