Reddit thread is locked and post/video removed. I've no idea why, the mods didn't even bother to mention the reason.

Already removed from Reddit...

I think you are referring to the transmission pin and “Strike Plate” in the 206 A/B. It was a witness indicator of excessive transmission movement not a restricting device.
the pin extended down into a rectangular hole which was surrounded by a thin plate riveted to the transmission deck. If the pin hit the plate with excessive force it could distort the plate or even shear the rivets. Usually caused by excessive lateral not longitudinal movement of the transmission.

A person claiming to be a helicopter pilot made a comment on that reddit thread they thought the aircraft was already at a high yaw before the initial separation. It looked like a small blob of pixels to me, even full screen so I was unsure, except for the identifiable helicopter profile. However there did not appear to be any maneuvering prior to the initiation of the spin. The end events of the removed reddit video was the same as that from the cell phone.

If it comes up again, the video looked to be a fixed camera pretty high up and looking between two buildings. The camera does not pan as the more often shown one does and starts before the breakup.

Would loss of tail rotor control at what looked to me like a fair cruise speed (100 kts?) result in this sort of breakup?

EDIT: reposted at: https://www.reddit.com/r/Catastrophi...ash_in_hudson/

RIP.....

https://cimg9.ibsrv.net/gimg/pprune....8656fb4911.jpg

https://cimg0.ibsrv.net/gimg/pprune....23810255be.jpg

Catastrophic failure of the gearbox. Tail-section snapped off as soon as the fuselage went sideways to the direction of travel. So many forces going on once it’s all out of balance.

Not a little different, it's totally different.

In the reposted video, the main rotor appears to break away well into the descent.

Similar accident to VH-ZMF in 2022 (accident report)

TLDR: VH-ZMF was B206L-1 Flying straight and level, until suddenly tail sliced off and rotor with transmission coming down separate to main hull and engine. report findings: likely bird strikle startled pilot causing abrupt input rotor took off the tail

From a recent update in the Courier Mail:

Just terrible.
Almost looks like the tail boom attachments have failed on one side, and its then folded around the fuselage.

Perhaps, since this is the rotary section, enthusiasts and non-pilots could just keep quiet, since this is not facebook, and it is challenging reading such drivel from some people who clearly have no clue about helicopters.

Dogtail - Yes, it's quite common in the pleasure flying world, with proper supervision, of course. The gazelle has a clutch so you can keep the engine running while the rotors are stopped.

Makes you think what? Were they all Longrangers?

Looks to me like the top bit of the gearbox came off, where the brown stuff goes.

A frame by frame clip shows a sudden yaw and the tail folding to the right. The rotor system appears to be under power at this point. The severed tail is struck as it drifts above the falling aircraft. The gearbox is the last to depart about a third of the way down.
On the surface it could be a catastrophic transmission failure.
There seems to be enough of the wreck remaining to come to a conclusive finding as to the cause.
Until then, it is just speculation.

Whilst I agree with your sentiment, there may well be a few engineers with valid observations. Pilots don't always have the answers.

Main rotor was clearly rotating/spinning, when it hit the water - complete with transmission. Tail separated before. Severe mast bumping would most probably cause mast breaking. My guess is, that tailboom was cut off by main rotor, then transmission separated. If you snap cyclic back on 206, mast bumping is inevitable, possibly with tailboom cutoff.

Happened to pilot I know well - he instinctivelly pulled back when terrain suddenly appeared in front of helicopter - tailboom cut off, hit the ground, skids torn off, but transmission held so he was able to autorotate (kind of) and both occupants survived with some bruises - after tailless and skidless helicopter "landed", overturned on its side, shattering M/R pieces all around.

Another one I am intimate with: (luckily on ground) pilot instinctively pushed cyclic stick forward, so no tailboom strike, but everything up from cabin roof was overhauled/replaced. (mast and M/R hub replaced, transmission overhauled, transmission mounts replaced. Aft transmision mount (flexible-rubber) was almost torn away)

My five cents guess: an instinctive overreaction on imminent collision with something (birdstrike, drone strike....) 206 is otherwise a sturdy, reliable machine. I worked on them many years. 206L has different transmission mounts, that I am not familiar of, but if it is a "nodal beam" principle, it is much more complex than simple A-frame on 206B - that probably can`t handle so much abuse as basic Jet Ranger transmission mount can. Obviously, tail was chopped off first, than main rotor with main transmission departed - my hypothesis explains that sequence. We will need to wait for NTSB report to, hopefully, know for sure.. R.I.P.

Huey’s.
 

It was Huey’s flying nap of the earth,push overs following terrain negative G unload blades tail detachment.They lost a few before they had a surviving crew that explained what had happened.

No argument there. They weren't intentionally left off the list.

It is inherently difficult to look at grainy, mobile footage and determine the root cause.
That is what investigations are for.
What is cause, and what is effect cannot be determined with the information that is available.

In the reddit video, there is a massive yaw to the left to almost 90 degrees followed by a slight swing back to course then tailboom appears to break under aerodynamic forces as the aircraft descends, following by separation of rotors and gearbox together. Could a gearbox failure stop the tailrotor causing a massive uncontrollable yaw to the left? (any B206 pilots can confirm this?)

RIP to all involved, a horrific and tragic accident.

I wonder if the tail rotor detached causing the spin, resulting the following unplanned disassembly.

Looks like mechanical issue causing gearbox/rotors to detach, or possibly low-g/abrupt control input scenario. All purely speculation of course.

What a terrible incident.

The loss of a T/R gearbox will also cause a large cg shift and nose-down pitch - the pilot might pull back to correct it and there goes the mast bump?

We lost a Huey in 1981 when a T/R blade separated, the unbalanced gearbox came out, fuselage yaw, pitch and roll, mast bump, rotor separation, blade came through the left cockpit, took off the tailboom, and all in freefall.

PLEASE READ THE THREAD BEFORE COMMENTING. Chances are, your thoughts have already been commented by someone already.

Whatever caused the tail to separate would have been felt by the pilot as a TR failure and we would all at that stage dump the lever - any cyclic input would likely be to try to keep speed (he won't have known the tail boom was completely gone) but he would have had zero directional control.

You can't simulate this type of failure and any control inputs the pilot made would have been fruitless.

What cause the separation of the MR and what looks like the top of the MRGB from the fuselage? Who knows, but in that condition the stresses must have been very high and any weaknesses in the transmission system would have been pushed to breaking point.

From the point of tail boom separation the chances of a good outcome are vanishingly small.

RIP.

Sadly, some of the drivel is coming from pilots too!

When you are humming along at 80-100kts and there is a sudden loss of drive to the trail rotor that does not result in a massive uncontrollable yaw. In forward flight you have a lot of vertical hardware hanging off the206L tail boom to give you some directional control. Lower the collective lever to reduce the torque in the rotor system and you're back in business with a fighting chance. Yaw to the left with loss of drive to the tail rotor in the 206?

Plenty of drivel and focus upon a single cause none of which is based upon any ascertainable fact(s).

However there is a gem of insight that serves to set the wagon back upright upon its wheels.

Thanks to Gullibell for offering his excellent insight, knowledge , and attention to detail which should serve as an attention getter to so many here.

The rest of you need to get back into the books and RFM for the aircraft you are flying (American versions and not the French or Russian versions).

Many comments down the Reddit post, someone has produced a zoomed-in version of the video which shows the whole accident. I'm too new to post URLs, but it's address is streamable dot com slash 56ttmc.

11 seconds into that, it seems to show a kink/break happen in the tail boom, which is prior to the uncontrolled yaw that happens immediately after.

The images are obviously very grainy, however.

Who the hell is this clown commenting for the UK Sun?

Well it is The Sun, would you expect anything less……

A disseminator of fake news? 'Cause there certainly is not much fact in that report!

”Aviation analyst Julian Bray suggested the critical component, which holds the rotor system in place, may have failed mid-flight and led to the deaths of all six people on board.”

https://uk.linkedin.com/in/julian-bray-515405258

Yep, the aviation expert picked it. The accident helicopter was the super stretched nine seat version...but I don't understand what the Jesus bolt has to do with any of this....and yes quite obviously the engine was working as the rotors were seen to be spinning after they detached from the helicopter body. Obviously I'm not as expert as he.

Although the image is grainy, it seems much more like yaw right than yaw left which would be consistent with a tail rotor/boom/drive failure on a US rotation rotor system.

After that with no directional control, survivability is unlikely - a vertical auto, if achieved would be difficult to maintain and assessing the height at the bottom to cushion the water entry would be nigh on impossible.

Very Terrible! No chance!
My “Guess” is that the Transmission/Nodamatic mounts broke and off it flew causing the other damage.
PS: I have over 20,000 helicopter hours on 13 different types, including the 206L.

It would be interesting to see the maintenance log, any corrosion related work and if there was any previous accident history.
Such a horrible tragedy, and little they could do to change the outcome.
What was supposed to be wonderful family trip and it ends like this.

Yep. My guess is your guess is on the money. They will unravel what happened soon enough.

This is the part they will be looking for. If the link assembly of the nodal beam system breaks you are in a spot of bother.

https://cimg0.ibsrv.net/gimg/pprune....ced6547047.png

First thing that came to my mind when watching the video was this incident from 2003…
https://asn.flightsafety.org/wikibase/188940

RiP Ian (Shoo), Neville and James.