Vance, I agree that blade weight loss "may be the cause of the crash at Forest Beach" . . . but that was not my question.Yes, I believe the loss of the blade weights may be the cause of the crash at Forest Beach.
My point is that ASRA's "real possibility" is not equal to "likely" cause.The text of the SD reviews the new information & observations that provide more information on the likely cause of the tragic accident in Western Australia!
Jeff, yes, she wrote the below:I believe Chris has already commented on the grounding and the latest ARSA directive
However, since ASRA has no jurisdiction here, I was wondering aloud if USA owners considered themselves grounded (i.e., on a prudent though voluntary basis).All our USA TAG owner's have received this information prior to the publication of the ASRA Safety Directive and are aware!
They have been Synonyms for a very long time.Kolibri;n1143394 said:...When did "Possibility]" become a synonym of "Probability"? ...
Apparant = Possible =Probable = Likely... My point is that ASRA's "Real Possibility" is not equal to "Likely" cause...
... Do you agree with Chris that it "appears to be" the cause? ...
There is a real possibility, therefore, that if such a massive instantaneous rotor imbalance occurred with the Forrest Beach Titanium Explorer, then the failure of the folding-mast side-plates would have been a secondary, rather than primary cause of the double fatality.
Jeff, since this SD is self-referential:That the ARSA is allowing on case by case basis to flight status is encouraging.
. . . one should infer such solely for 1-piece masted machines which are not affected byASRA may progressively lift this grounding order on a machine-by-machine
basis once the following steps in relation to each machine are undertaken:
I wonder also; it's possible.Given that The ARSA apparently missed the balance weight on this machine, one would wonder if the other machine may also have slung a balance weight.
. . . I question the strength of a mast that would break from the imbalance.Whilst cutting the rotor blades to facilitate easier disposal, he noticed that a leading edge balance rod was missing.
He finally discovered that the end cap of the same blade was also missing.
The whereabouts of the missing rod and end cap is unknown.
This observation raises a real possibility that the balance rod had departed the Forrest Beach Titanium Explorer rotor under centrifugal force during cruise, which – if this occurred – would have resulted in an instantaneous and massive rotor imbalance. Where massive in-flight rotor imbalances occur (in helicopters), it is usual for the rotor support structure to fail almost instantaneously as well because the imbalance forces are so extreme.
There is a real possibility, therefore, that if such a massive instantaneous rotor imbalance occurred with the Forrest Beach Titanium Explorer, then the failure of the folding-mast side-plates would have been a secondary, rather than primary cause of the double fatality.i would think that the balance weight being slung by the blade striking something I would expect to see damage to the blades leading edge. I do see in the photo that the fiber matrix of the end of the blade is pushed out. Not knowing the weight of the balance, it’s size, or the diameter of the rotors, I would wonder how much inbalance say a one pound weight at at say eighteen feet would cause. Not only would the rotor be out of balance in the rotational plane, but also the blade would now be out of balance in the balance in the chord. Would this also cause a flutter condition in addition to the rotational inbalance? Three inches missing off of a fixed wing aircraft propeller can set up a severe enough vibration to damage the aircraft. Loose enough propeller blade and you might pull the engine off its mounts.
In my opinion no mast can survive a severely out of balance rotor at flight RPM for more than a few seconds so the missing rotor weight and end cap appear to me based on what little information I have to be the likely cause of the Forest Beach accident and the broken folding mast plates the result of the rotor imbalance.Kolibri;n1143492 said:Vance, I agree that blade weight loss "may be the cause of the crash at Forest Beach" . . . but that was not my question.
Do you agree with Chris that it "appears to be" the cause? You earlier implied that it did with your "Glad they figured it out Chris."
My point is that ASRA's "real possibility" is not equal to "likely" cause.
This has not yet been "figured out" and it is inaccurate to claim so.
I think that she somewhat undermined her own credibility by overstating that ASRA's SD asserted probability (when it did not),I feel your focus on semantics is a not too subtle way to attack Christine’s credibility.
Without higher-res photos, it's difficult to tell, but you make a good point, Jeff.i would think that the balance weight being slung by the blade striking something I would expect to see damage to the blades leading edge.
Vance, it would seem that would depend on how much weight was lost, and the strength of the respective parts. Not all gyro masts are equal.In my opinion if a gyroplane rotor blade pitches a nose weight in flight it is a non-recoverable event no matter how strong the mast is.
JAL, that is some logical reasoning.The fact that this has only happened with the folding mast version suggests to me that the mast broke first and then the blade end caps came off. If it was blade problem then it might have happened to a none folding mast version as well. Not to say that it cant happen but it in my mind there seems to be much of coincidence, however, that not to say it couldn't happen but when in doubt the law of averages is all you have.
I don't know enough about the Titanium Explorer folding mast to have an opinion about its serviceability.Kolibri;n1143580 said:Regarding the TAG mast plate design, are you saying that it's at least adequate as is?
Vance,Vance;n1143572 said:In my opinion if a gyroplane rotor blade pitches a nose weight in flight it is a non-recoverable event no matter how strong the mast is.
Something is going to break and in this case it appears to me the plates in the folding mast were the weak point.