While one of the pitch links is clearly visible (1), I previously thought the other was missing, but I think part of it is visible hanging from its connection point on the swashplate (2). Is that what others also interpret that as? The scissor link from swashplate to mast (3) still seems intact:

https://cimg3.ibsrv.net/gimg/pprune....002d6a9770.jpg

I couldn't find a good photo showing typical arrangement of intact pitch links on a Long Ranger, but as a comparison, the following photo shows them on a 206B which is probably similar. Scissor link happens to be facing forward on this photo but of course it rotates with the mast:

https://cimg6.ibsrv.net/gimg/pprune....a31297aa07.jpg

It wouldn’t surprise me if there’s a jumbled mess of metal inside that gearbox casing. It would explain why the rotor mast no longer sits perpendicular to it (question is - is the mast bent or merely displaced off to one side).

The amplitude of the vibration from the VH/Nodal Beam interaction is reported as being incredibly severe. More like ground resonance, not something that would cause long term fatigue damage. Being that it’s a harmonic, it would get worse very rapidly. The previous incident in Washington had the tailboom almost completely ripped off within seconds of the onset of the vibration.

Anyone that’s seen the sad state of many agricultural 206/OH58 roof structures would agree that it is highly unlikely this is a fatigue crack that let the roof go. When you hear popcorn crackle as you walk on the sides of the roof, you know it’s not in good shape, but you never hear of ag ships chucking their roof. I’ve flown 206s with pretty severe structural issues in the roof (not to mention 3-4x the total hours of the NY machine), even under heavy use at max GW, they just slowly make mud and smoke rivets.

https://cimg0.ibsrv.net/gimg/pprune....b5ea2a6b5c.jpg[/QUOTE]
An interesting detail: on the bottom of fuselage, (between two NTSB men standing) there is a little square - looks like rad alt antenna? If it is truly rad alt antenna, arrow should point into the direction of flight. On that square thing it shows to the left - 90 deg. off the flight direction. Misplaced during crash or incorrectly installed? Anyone has an idea? Is it possible that this (small) helicopter has radalt installed?

In the United States all part 135 operation helicopters have to have radar altimeter installed.

We run Van Horn main rotor blades on one of our 206 L4's and have not really seen much problem with the bounce that people are describing. The only reason why we went with Van Horns is because Bell helicopter could not supply new blades until "sometime in 2025". They could not give me a firm delivery date and we were out of time back in August of last year. They were our only option. I was a little bit Leary of them hearing about all the difficulty with the 206 B model blades but supposedly the L model generation 2 blades were better. We probably got 300-500 hours on them with no issue. The only thing I find weird about them is there's no trim tabs you use tracking wedges which are little stick on wedges that act as your up or down trim tab adjustment for tracking.

To add, the honeycomb roof panel does not carry the flight loads and where the roof panel failed is only honeycomb. The flight loads are transmitted from the nodal system to the roof beam which basically sandwiches the roof panel between it and the nodal mounts. The yellow structure in the pics still attached below the nodal system is that beam.

What failed was the beam attachment to the forward and aft roll beams which in turn connect to the floor panel or tub that carries all the weight. While this load path is bullet proof in normal loads, if you were to rotate the blades to the 3/9 position and applied enough force to the one of the blade tips you could tear out the roof beam and MR drive. Its happened before with MR impacts.

Radar altimeter antenna can be installed laterally as shown provided they are indexed properly. On helicopters, with its limited mounting real-estate it can be a challenge sometimes to mount rad alts.

A partial screengrab from the NTSB B-roll video, showing the tail boom failure point. The investigator is holding a torch, the black shaft is not part of the aircraft.
https://i.imgur.com/rgMz6dg.png

The full video source is here:

That is the cleanest inside of a 206L tailboom I've ever seen! Must be a very new installation or there are some incredibly diligent maintenance folks.

Here is the best explanation so far---not mine BTW, I tend to agree and am merely copying it:
Turn sound on!

We have all seen this one at this point but depending on where you watched it, the media scrubbed the audio off of and talked over it. Slow it down, you will clearly hear the sound of a tail rotor drive shaft impacting the metal of the tailboom. Those of us that have had this done in the simulator will immediately pick up on the similar sound. This sound precedes all visual cues. Use the visual impact of the fuseluge hitting the water and the appx 1.5 seconds of delay before the sound reaches the cameras microphone. Now go back to the beginning of the video and when you hear the first thump, go back 1.5 seconds and keep replaying that. It will be become clear that the sound precedes the yaw to the right. What you hear happens 1.5 seconds before you hear it. You can hear the rpm of the sound stays fairly steady and stopping after 2 seconds. What lines up with 2 seconds after the visual of the incident beginning? The main rotor impacting the free floating tailboom.

With the wreckage photos we have now, the tailboom to fuselage joint is intact but it is broken at the next segmented ring frame. That at least removes the theory of the 4 bolts or any of the frame being an issue. That same video above if slowed down and zoomed in there is a frame or two that shows the tailboom completely separated from the aircraft and intact fly up and into the main rotor where it gets cut in two pieces that we can track till water impact.

The wreckage photos also show the top of the fuselage is torn apart and paint removed directly below the driveshaft behind the hangar bearing bracket, the bearing is completely gone.

A tail rotor driveshaft failure starts the right yaw as the tail rotor begins to slow immediately. At the same time, the engine side of the break in the driveshaft is now flailing around and hammering the top of the tailboom, a coupling or bearing failure allows this much movement to occur. This weakening of the tailboom happens instantly and the aircraft yaws to the right putting the tailboom way out into the 85-90kts of wind and puts so much load on it that it fails. This allows the yaw to continue past where most of us would expect the weathervaning to have stopped it. The tailboom folded as it went out into that airsteam because of its weaken state. You can actually see that happen when you watch the fuselage begin its first few degrees of yaw but the tailboom does not follow it.

The tailboom now completely free of the fuselage, which happened as the body of the aircraft gets between the camera and the boom turned almost vertical and was only then cut by the main rotor and we clearly see that in the video. That forced being applied to the rotor system created such a reactionary torque and imbalance in the system that main rotor system torn itself from the airframe but it took an additional 2.5 seconds of force being applied before the transmission and rotor system pulled inself along with the airframe off the rest of the fuselage. The main rotor continuing to spin at a very high rpm all the way to the water. There is absolutely no seizing of the MRGB that would have the rotor system come to complete stop and then restart again after tearing itself out of the aircraft especially when we can see in the video that the rotor system never stopped spinning till it impacted the water.

There’s an extra piece that is not being reported but I’ll add to this discussion. For 2-3 days prior to the accident n216mh’s tailboom was wagging excessively while on the ground at KJRB. This was mentioned to the pilots multiple times by other pilots, ramp agents and even over the radio by ramp agents running the radio upstairs. They reviewed the security camera footage after the accident and it clearly showed the tailboom wagging far more than any other aircraft. This footage has been provided to the NTSB.

I initially took that as a potential weakening of the 4 bolt connection that then was allowing an otherwise perfectly balanced and working drivetrain to wag the tail. Other option was an imbalance anywhere on the tail rotor drive train was creating the wag which over time was weakening the 4 bolt connection. Once the wreckage photos showed the fairly clean break at a location that was NOT the 4 bolt connection then I moved on.

This extra detail is pointing towards a serious bearing/coupling drivetrain issue that had been working itself for quite sometime and finally failed and became a wrecking ball to the top of the tailboom.

I saw this the other day when these pics were posted. The other rad alt antenna has it's arrow facing inboard also. They are typically mounted with the arrows facing forward, but I looked it up in the KRA-405B installation manual and it does allow the arrows to face each other as an alternate. See quote below, bold and underline mine.

I saw this post on that other site also. I added there and will repeat here, if you watch that video around the 6 second mark when the aircraft is still to the left of the building you will see a puff of smoke, or maybe a piece of debris, or maybe it's just a video artifact. Screenshot:
https://cimg7.ibsrv.net/gimg/pprune....c1628f86b0.png

I believe the tour company involved, has ceased operations.

So that beam attaches somewhere in here?

https://cimg4.ibsrv.net/gimg/pprune....3e9832ad78.jpg

Interesting theory. But tailboom wag is a sign of either the MR hub trunnion is out-of-center, the blades and hub were not aligned properly during build up, or a blade was swept too much during track and balance. This is usually only noticeable at idle and smooths out at 100% ground idle. The only fix is to remove the blades and check the trunnion/alignment which doesn't always get done in a timely manner. Regardless, have seen many 206Ls have this "feature" with zero issues and is usually corrected with the next MR removal or pilot complaint he can't fill out is flight sheets during cool down. Any TR drive issue will have a noticeable buzz in the airframe and if the TR was so out of balance to wag the t/boom, well I don't believe that was the problem here. But I think his point of possible shaft damage to the t/boom skin led to the failure has merit and it wouldn't take much damage given minimal damage limits allowed in that quadrant and especially under flight loads.

Three words: Van Horn Blades

From Gordy's post:

What would a reasonable person do upon being told such?

This would be a starting point for an Investigator to look into I would think.

I have no doubt that shall be thoroughly reviewed and many questions asked of everyone involved.

Looking really close and slowed down, it almost looks like he yawed there too...

Agreed, and using string and mirrors is maybe not the best of alignment tools, I was grounded for 2 days a few years back when my mechanics were trying to align an older blade with a newer one---interesting procedure......

I still think this explanation is getting closer....

To piggyback on Sultan's AH-1W incident anecdote

(to be fair the exploded view below is the VH 206B blade, and the LongRanger version is a little different, but relative weight pocket location is about the same)

https://cimg0.ibsrv.net/gimg/pprune....504db988ba.png

The red arrows show where the roof beam would have been attached to the roll beams: the RH red arrow just aft of the servo web/broom closet and LH red arrow/circle area where the aft roll beam should be under the fwd firewall. The RH blue arrow is the forward roll beam and the LH blue arrow shows the remains of the aft roll beam. For reference the yellow arrow shows the engine deck and the green arrow shows a portion of the roof panel that remained attached to the fuselage.

https://cimg6.ibsrv.net/gimg/pprune....4ae305fb2a.jpg