FATAL - Cavalon G-CKYT, near Avoch, Scotland, UK 12 NOV 2020

Wonder what will cause the head to separate from the craft? This is very disturbing 😳
 
Wonder what will cause the head to separate from the craft? This is very disturbing 😳

Extreme vibration due to huge imbalance in blades. Cracked mast composite structure that was not caught in inspection and grew inflight.
Could also be an unloading accident where the rotor blades became so deformed that caused excessively vibration, cracking the mast assembly or causing flutter at the right frequency to cause it to crack.
The last one being more likely.
 
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Looks like auto-suggestion for vibration.
 
Extreme vibration due to huge imbalance in blades. Cracked mast composite structure that was not caught in inspection and grew inflight.
Could also be a unloading accident where the rotor blades became so deformed that caused excessively vein ration cracking the mast assembly or causing flutter at the right frequency to cause it to crack.
The last one being more likely.
Thank you for the reply, one question that comes to mind is why did the pilot not feel the need to land with such high vibration? Or take off knowing the aircraft clearly has an issue?
If what you say is correct then this vibration had been present for a while? In my experience we get vibrations that are present that are not harmful to the airframe, rather just annoying, in this case the vibrations must have been substantial to cause the airframe to suffer that damage in flight? Also the damage would have occurred over a few flights ? IMO. We had a case in SA a few years back where a composite blade started to delaminate during flight and the pilot heard what he described as a gun shot going off during the advancing rotation, he landed it and lived with a damaged back

Regarding the blades, did this Cavalon have composite blades? As I’m unsure if aluminium blades can deform in flight at rotational speed, and if the speed did decay because of prolonged negative G that we all agree needs a few seconds to introduce then would the blades not have hit the tail or prop? Just asking I’m no expert, rather wanting to learn as much as possible
 
Thank you for the reply, one question that comes to mind is why did the pilot not feel the need to land with such high vibration? Or take off knowing the aircraft clearly has an issue?
If what you say is correct then this vibration had been present for a while? In my experience we get vibrations that are present that are not harmful to the airframe, rather just annoying, in this case the vibrations must have been substantial to cause the airframe to suffer that damage in flight? Also the damage would have occurred over a few flights ? IMO. We had a case in SA a few years back where a composite blade started to delaminate during flight and the pilot heard what he described as a gun shot going off during the advancing rotation, he landed it and lived with a damaged back

Regarding the blades, did this Cavalon have composite blades? As I’m unsure if aluminium blades can deform in flight at rotational speed, and if the speed did decay because of prolonged negative G that we all agree needs a few seconds to introduce then would the blades not have hit the tail or prop? Just asking I’m no expert, rather wanting to learn as much as possible

If the vibration set off flutter, it could be over before he could land.
Aluminum blades would not deform in flight but would crack with pre-mature fatigue. Cavalon in UK likely had their Aluminum blades.
Also given recent finds we cannot discount possibility of blades cracking at the clamping bolts discounting their 2500 hours life. But they would figured that out by now so I doubt it is that. For a much geekier in-depth look grab a coffee and watch

 
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If the vibration set off flutter, it could be over before he could land.
Aluminum blades would not deform in flight but would crack with pre-mature fatigue. Cavalon in UK likely had their Aluminum blades.
Also given recent finds we cannot discount possibility of blades cracking at the clamping bolts discounting their 2500 hours life. But they would figured that out by now so I doubt it is that. For a much geekier in-depth look grab a coffee and watch

The vid is not available ?
 
If you guys are outfitting of road exploring gyros, I would not only look at tube type tires but a repair kit of JB weld, super glue, some baking soda and a small pony bottle of fuel one or two spare plug wires and plugs and some small Knipex slip joint pliers.
Good tips Ben.
 
Good tips Ben.
I would add to this kit loadout one of the small foldable fuel bladders made by companys like platypus.
Any of you guys have ever seen videos or personally seen me flying my lightning back in the day would have noticed an upside down 5 gallon Blitz gas can strapped under my engine. It was a "come home bottle". It was empty and just because I used to fly open desert all the time, I would land near a gas station and if I couldnt taxi up to the pump, I would unstrap tank, fill it, transfer to seat tank and restow it.
Also a Smith and Wesson 317 Airlite revolver 22lr is a good companion a d weighs next to nothing.
 
Thats a good one, but a bit big for pocket carry
 
I think we don't need to get too carried away here.

I very much doubt the AAIB will find some definitive smoking gun with this one and as I've said before I think the delay is process driven in so far that because nothing can be proved 100% and the category of aircraft is not very numerous / not public transport there is limit to how far their findings will be allowed to be extrapolated because [in my view] the associated critique.

Their statement however is very clear:

The investigation is focused on understanding the circumstances which led to the rotor head separating in flight.

Analysis of recorded data from the accident is now complete. Further testing of the rotor head is ongoing. Once this testing has been carried out and the necessary analysis completed, the AAIB will publish its investigation findings in a final report.

Either overloaded because an aircraft with correct and acceptable engineering was flown far beyond something that may be required to be able to withstand or not. Of course if it is the later the remedy has a lot of consequences.
 
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