Video Helicopter Crash Rowlett
 

Caution it’s not for the faint hearted.

Very dramatic situation on such a beautifull weather day.
I anticipate crash investigators will gather a lot from that tape.

investigators might use the video ?
So sad. Rest in peace the crew.........

Yes, because it shows they where to look for the (otherwise unscathed) tail plane.

In the comments here somebody claims to have witnessed the tail rotor coming off.

See also Accidents. R22/44 Tail boom events.

R16.

Unless I misunderstood your post, the separated tail can be clearly seen on the video's
https://cimg6.ibsrv.net/gimg/pprune....fb363728d0.jpg

His statement sounded like it was about a lost tail rotor before the loss of control and the boom being hit.

can you point to who/where the comment on the TR comes from please?

One of the eyewitnesses indicates the helicopter was in a hover (OGE...) and then there was a pop....

If the RPM is normal, in the OGE hover the fact that the head is a semi-rigid design, (hybridized from a teetering head to a teetering + coning hinge for root load relief) is basically immaterial. Cyclic inputs on a Robbie like any civil helicopter should be smooth and coordinated, but the hover is not a point that modest cyclic inputs will compromise TPP/tail boom clearance. High speed, very different story. A TR drive failure will get out of sorts in a high hover quite quickly and will result in reduced TPP/tail boom clearance unless the throttle is closed, but there is a few seconds before it gets wild from the inertial moments on the fuselage feeding back into the control system. The video indicates that the NR was likely maintained for the early parts of the event, the blades had not suffered an underspeed event resulting in blade stall (the SN "LOW RPM STALL") the rotors only appear to come out of plane after the pitch over and presumably the engine stoppage from fuel pickup point catching air. This doesn't say one way or the other if the pilot had closed the throttle and entered autorotation, it is probable the event wasn't from an engine failure, however. So, the rotor control head itself is unlikely to have been bad, no pitch link failure, no coning hinge failure, an accidental forward whack on the cyclic is very uncomfortable in the hover but doesn't normally result in a tail strike (there is a neat video somewhere of that being done at a low hover, and stuff happens but the tail didn't get cut off). The same forward whack at 115KIAS is pretty much deadly.

The losses in the RHC are a mixed bag of causes, the fact that it has become the universal training helicopter with the minimal production of any other entry-level chopper other than the Colibri (which has a pretty neat head design) and a smattering of others. The rotor head needs operational care by the pilot, as it did on the B206 and UH1B/H etc... or 2 blade AH1s. They are not forgiving of bad habits, but then, the guys & girls who train the pilots in them take remarkable care to cover those matters, as does the Manufacturer. The RHC Safety Course is a worthwhile course for any person flying them, CoViD notwithstanding.

Sad day for all concerned, fortuitous location of the incident.

This video mentions that it was a training flight.

My initial thought was perhaps mast bumping but not severe enough to sever the mast. Before everyone jumps on it it’s just a speculation and I realise that would be unusual.
Another thought I had was if I remember correctly the tail rotor detached at the input in the 44 accident in Broom Western Aus, Perhaps another gearbox failure?

Was there a conclusion from the investigation into the Broome crash?
There might be a disturbing pattern occurring.

While not impossible, it would seem extremely unlikely, that pilot error during the reported high (OGE) hover could sever the tail boom.

Catastrophic and unrecoverable mechanical failure is most pilots worst scenario.
When caught on video, the impact is chilling, and can have a deleterious effect on product confidence.
EC225’s are cheap to buy, for EG.
I’m less and less happy to board B737’s (and too scared to watch “Downfall”)

What about Low-RPM Rotor Stall? Perhaps they were doing SWP recovery (the most common reason training flights in Robbys pull into a high HOGE) and something went wrong?

Yes it was mechanical failure of the gearbox at the input. There had been a vibration reported by the previous pilot with ground trouble shooting not finding any faults. Next flight it failed on vertical departure.
I could be incorrect but if my memory serves me right the tail severed and looked very similar the tail rotor in this video.

No report as such, however there was a rumour floating around when Broome R44 happened that it had been towing a water-skier a few days prior to the incident. Broome was different to this one as the blade failed and presumably caused the transmission separation.

For this one supposedly they were training VRS recoveries... perhaps the student staring at the ASI dropped the nose too much with the collective on the floor, the already high RoD leading to freefall, low G then tail off.

I would really like to know what happened but I doubt we will ever find out.

At the beginning of the video the MR RPM appears “normal”. No excessive “coning” or other signs of low RRPM.

Good point though re Vortex Ring. Over controlling in the potential turbulence present during incipient VRS is a possible explanation. EG Nose drops, sudden aft cyclic application.

Or an over-zealous recovery, lowering the lever and pushing the cyclic forward followed by a check back on the cyclic to control the nose-down.

Simply lowering the lever too quickly will reduce positive g and can even take you to negative - we all know the dangers of that in a Robbie.

Sorry Twist and Shout the Broome accident hasn’t been finalised, my mistake. It does look like a similar detachment point though.

VRS is interesting possibility especially if it’s known that was the training sortie. A friend of mine ended up on his back in a 500 teaching VRS when it bit back and rolled right over. Luckily it was a 500 as there are not many aircraft you’d get away with that in.

On a high inertia rotor you are absolutely correct. On the RHC, in the OGE hover the recovery time is minimal. RHC estimated a tau of around 0.7 seconds for the R-22, which is shorter than the response time required under the FAR for test. It was accepted on the basis that as it is a critical manoeuver the pilot would respond immediately. The R-44 has a better tau but is still not long, the response to an OGE throttle chop is an immediate descent and a rapid loss of Nr. For the R-22, I recorded in an STC series an OGE Nr drop from 104% to 89% in 0.5 seconds, with no perceptible dwell time on the collective. The attitude was recorded for the test helicopter, as well as accelerations, around the CG, blade root loads, both bending and torsion loads, and pitch link loads. Stall Nr was measured for the stable IGE hover at 82%. The mod lowered that to 78% and one configuration got that to 68%. For a Robbie I doubt that anyone teaches or does a delay in lowering the collective in an OGE throttle cut. lowering the collective rapidly itself doesn't give much of a pitch change, the yaw pedal input makes more of a difference to the trim and to the attitude if not corrected quickly. FWIW, my own view is that OGE hover in the RHC is not for the faint-hearted or anyone who is not up to speed. It is required to be trained which apparently this incident was a training flight.

I'm basing my suggestion on the Gazelle in which I have done OGE hovering and throttle chops but also the Sea King where we trained for forced landing from an OGE hover when we started a lot of FLIR searching.

In both cases, initiating with rapid down collective produced a nose down pitching and a reduction in g.

If this doesn't happen in Robinson aircraft then I'm surprised but happy to have my knowledge improved - not that I'll ever get in one of them again!