Propeller safety

[Roundsounds]

Timely CASA article released today:

 

http://www.flightsafetyaustralia.com/2014/03/properly-clear-of-the-prop/

 

 

[2tonne]

Timely CASA article released today:http://www.flightsafetyaustralia.com/2014/03/properly-clear-of-the-prop/

That was close!

 

 

[facthunter]

So we agree to treat them as though they are alive? There is a lot of complacency around due to the Rotax and Jabiru's having (supposedly) a requirement to be doing a fair few revs before there is any spark. When an engine is cranking it's revolutions don't show the full situation . At the "moment" the motor is going over compression it is hardly turning at all. Similar situation to when it's idling slowly. Nev

 

 

[Bruce Tuncks]

Has it really happened with a Jabiru engine? I know it is theoretically possible but never heard of it in real life. I am thinking of turning over a hot engine and having it fire.

 

 

[David Isaac]

You cannot be certain of any cutoffs or switches so you should always treat props as live and if they fire you wont be surprised or sliced or diced.

 

 

[Bruce Tuncks]

Yep David that's the right advice and what I follow in practice. Except that I always turn the prop over ( carefully ) as part of the engine inspection at the start of the day, and sometimes do this with a warm engine during the day. The reason is to find out if the engine is ok .

 

There was a good pilot I knew who had an engine failure in a Jab and I asked him how it felt on turnover that morning. He had never heard of the turnover check, and I think his instructors had been excessively fearful of inadvertent starting. They might themselves have learned on impulse magnetos, which the Jab does not have.

 

 

[David Isaac]

Right on Bruce. It doesn't matter what engine type, a hand turn over at least before first flight on any day IMHO is essential to have any indication of at least part of the mechanical engine condition.

 

 

[Soleair]

Lucky my MZ202 engine has a centrifugal clutch then, that doesn't engage until the engine reaches 1900rpm.

 

Though it does make hand prop starts a tad tricky. . .

 

 

[Yenn]

I was trained that part of the preflight / daily inspection was to turn the prop to ascertain that there was usual compression. I have done this with Rotax, Jabiru, Lycoming, Continental and slso radial engines, with never any firing of the mags. I am aware of the risk and act accordingly, which makes it a safe procedure. It is the being unaware of the risk that will make it unsafe.

 

 

[facthunter]

I wouldn't fly a Jabiru without hand testing the compression. It's part of the normal preflight as far as I'm concerned. I'd like a good meal for everytime I've written here to get a good motor and find out what it feels like and you can compare yours with it, once you know what you are looking for. With planes with no starter, you got to feel this in the normal course of priming and starting. You don't wait for the 100 hourly to tell you. This is especially important with a plane used infrequently. Nev

 

 

[dutchroll]

With a radial you're more concerned over whether there is oil accumulated in the bottom cylinders, so a pull through on the first flight of the day is essential to negate the probability of causing an expensive repair job when you hit the starter switch.

 

Prop safety is largely common sense and due diligence. Methodical pre-flight and post-flight cockpit checks of the position of your engine/fuel controls and switches before touching the propeller coupled with sensible technique will mitigate the risks. As with everything in flying, it's about having a bit of respect for the machine every time you walk out to it and not taking anything for granted.

 

 

[facthunter]

You need to have a discipline and sometimes that is lacking. Doesn't work with aviation. Some get careless with familiarity and dispense with checks, regarding them more the province of the beginner. WRONG. Bad example and often bad result...... eventually.. Nev

 

 

[mAgNeToDrOp]

Timely CASA article released today:http://www.flightsafetyaustralia.com/2014/03/properly-clear-of-the-prop/

Damn, my blood ran cold there. Very lucky.

 

You'd also want to make sure the brakes are on if you're in front of that prop....

 

 

[Subsonic]

Wouldn't the pull through practice best be done from behind the prop then? I guess you'd stand a better chance of being bounced out of the prop arc than if you were standing in front of it. Also if the aircraft moves, you're already behind it.

 

 

[dutchroll]

Not practical or safer on mine, for a number of reasons, not least of which being a taildragger with tall main gear causes the down-going blade to be angled towards your head if you're behind it and standing straight or pulling downwards, and it's cramped space immediately behind the prop. But on some aircraft that could be a better way.

 

 

[mAgNeToDrOp]

"arc of the prop" danger zone probably includes a couple of meters in front in case you forget the brake, or brake failure etc. Use bloody huge wheel chocks :)

 

 

[Roundsounds]

Propellors are like guns, when handled by persons with care, knowledge and proper training they are safe. I've been handling propellors, including hand starting for over 30 years without incident. I was trained properly and treat prop's with the due caution and respect they deserve. I pass on the knowledge and skills to my students, not all learn to hand start, but all learn how to handle a propellor safely.

 

 

[aj_richo]

Has it really happened with a Jabiru engine? I know it is theoretically possible but never heard of it in real life. I am thinking of turning over a hot engine and having it fire.

I'd be just as wary of a Jabiru engine, maybe more so.. especially since the cold start kits came on the market

 

 

[facthunter]

A lot these days do it from behind. I prefer the front, especially on taildragger planes, for the reason Dutch has said.

 

4 cylinder motors are easier, as you can set the prop up to be in the right place.

 

From the front you can place your hand on the curved part of the blade, not the trailing edge which is very sharp and you really need gloves. When you swing you move away from the prop each time you swing a blade. If you stumbled you would fall a long way from the aircraft. The aircraft should be chocked and someone at the controls working the throttle and switches. If there is only one impulse fitted that is the only mag you select to start the motor, as the other one is set more advanced, and IF it fires it may make the engine kick back against your hand. Actually the impulse retards the spark by it's delay in the spring mechanism, and once the motor is running it resumes the running timing for the engine, as the impulse doesn't engage. Nev

 

 

[turboplanner]

I'd like a good meal for everytime I've written here to get a good motor and find out what it feels like and you can compare yours with it, once you know what you are looking for.

Don't worry, I'll get on to meals on wheels for you.

 

Some verygood posts

 

 

[DGL Fox]

I found this very interesting video on hand propping and prop safety in general....

 

David

 

 

[Bennyboy320]

Way back in the early 80's I flew the Tiger Moth at the RNAC, when doing the conversion I was taught their way of swinging the prop for an engine start, you would stand behind the prop next to the engine bay, with one hand on the hand hold on the engine cowl & the other on the prop, this way even if you slipped you couldn't fall into the prop, image that, they taught (TEM) threat error management & common sense BEFORE it was an official course & subsequent exam. Bring back the 80's were sex was safe (pre AIDS) & flying was fun.

 

 

[facthunter]

And for about 35 years prior to then they taught it by standing at the front, as the RAAF did, so you had your hands flat on the front of the blade as I have described previously. With a tailwheel the prop is tilted and if you are behind the blade as it turns you must go forward and you have your fingers on the sharp trailing edge of the blade profile. I will stick to the way I was taught previously but with a tricycle I go behind the prop as the arc is vertical. I consider it to still be more dangerous . Nev

 

 

[Roundsounds]

The common theme seems to be receive proper training before handling propellors. The thread started with concerns over untrained people being positioned within striking distance of propellors for photography purposes. I totally agree this practice is dangerous, but it is self perpetuating - pics of people draped over props set the standard for others. I will not allow these types of pics to be taken, my preference is to have pax stand behind wing / strut for souvenir shots.

 

 

[Guest ozzie]

At Luskingtyre I've noticed pretty much a 50/50 mix of preferences to standing in front or behind when hand propping Tigers. I've done a fair amount of hand propping from my old ultralights to Tigers, C182s and the odd Islander. The bigger engines I tended to stand facing in the direction that the prop turns instead of directly facing it and walk it thru the pull rather than trying to swing it through. That way i am pretty much at arms length and my body is out of the arc when it fires. No matter how ready for the thing to start I still tended to jump when it did.