ORIGINAL: paf
ORIGINAL: Gordon Mc
Sounds like something's wrong with your engine.
I'll tell you what.... if I give you the choice of sticking your arm into a 34 inch prop running at full bore, and doing the same for a prop that's windmilling lightly 5 seconds after being shut down on an engine that apparently has little or no compression - which would you choose ?
Given that you assert point blank that PCM set for engine kill could not have made any difference to the outcome of this event, either you have documented proof that the fatalities were not in any way attributable to the prop, or you believe that being struck by such a prop at full power can't kill you -- which is it ?
Gordon
What I'm saying is that, both the plane with windmilling prop and the fast spinning prop on its own, have enough energy to kill you several times over. Just shutting the engine does not make the plane safe - just a bit safer. From the video, I'm not able to tell if the engine was set with PCM idle failsafe or not, but even with the engine shut, there wasn't enough time for the plane to slow down to a non-deadly airspeed. I doubt that both victims got a direct prop hit, suggesting to me it was purely the total mass/velocity of the thing that did major part of the damage.
So, basically it seems you are now admitting that you have absolutely no hard data as to whether the injuries & fatalities in this case were caused by an impact to the head, or a prop cutting a vital artery, or even someone having a heart attack coz he got a heck of a scare... and you're just guessing - in which case your point blank assertion that PCM
would have made no difference there is simply invalid. If you don't have hard facts as to what the COD was, then you don't know that a programmed engine kill would have been totally ineffective as you clearly asserted. I can no more accurately say that engine kill would have saved either of those lives, than you can say that it would not have. We simply do not have adequate facts from which to make such bold assertions.
Now you're saying that you doubt that
both victims got a direct prop strike... so you're apparently no longer dismissing the possibility that at least ONE of them was hit by the prop -- and even in the event that only ONE of the two victims was killed by injuries inflicted by the prop, that's still one too many is it not ?
The major advantage of killing/idling the engine with failsafe is that hopefully, in most scenarios, the plane will impact at lower speed than with an engine running. However the plane has enough energy to be deadly several times over even with the engine dead.
P.
Lower speed is only one of the important advantages when it comes to large aircraft like this - removing the killing power of a large prop being swung by a large number of horsepower is a vital consideration, and one that can be largely controlled by appropriate use of engine kill upon failsafe activation. (Same goes for turbines - killing the engine on failsafe is not just to reduce speed, it's also to cool the engine as much as possible before impact, to reduce the risk of a fireball). Just because there are additional ways to be killed by the model (such as impact to the head), that does not in any way justify us ignoring our ability to remove or reduce as many of the risk factors as possible.
Seems to me that we should be considering what tools and procedures we have at our disposal and examining how we can best combine them to reduce the risk that our hobby poses to life & limb, rather than dismissing tools as "that wouldn't have helped at all" when we don't actually know that that is in fact the case. Let's try have an open mind as to what can be learned from this terrible tragedy, rather than closing off various avenues of learning due to personal preconceptions.
Gordon