R44 crashed Alps
 

https://www.heli-archive.ch/en/helic...APK12uRztFDaGc

one died, one survived.
Rescuers had problems finding the ELT (Reflections from the mountains?)

Other fixed wing pilots reported strong gusty winds between 25 and 35 knots in the area

From WIKI with some links

https://aviation-safety.net/wikibase/244398

Owner/operator: Private Registration: I-OLLI C/n / msn: 11439 Fatalities: Fatalities: 1 / Occupants: 2 Other fatalities: 0 Aircraft damage: Written off (damaged beyond repair) Location: Cervinia (AO) - https://aviation-safety.net/database...flags_15/I.gif Italy Phase: Unknown Nature: Private Departure airport:
Destination airport:
Narrative:
The helicopter crashed at an elevation of about 3000 m in the Alps. Both occupants had going skiing and were flying back at 16:00 hours local time. The helicopter did not arrive at the destination and an ELT signal was detected.
Sources:
https://aostasera.it/notizie/cronaca...-ed-un-ferito/
https://ansv.it/incidente-nella-valle-daosta-2/
https://www.bresciatoday.it/cronaca/...gio-oliva.html

For anyone unfamiliar with the area, here's a topographical map. There's a helicopter mountain landing site just on the Swiss side of the border (where "Rifugio" is marked) near the 3444m elevation mark, so it could be speculated that they landed there as it is provides access to a ski resort.
https://cimg0.ibsrv.net/gimg/pprune....ad69ea999e.jpg
Topographical map of the area. The Swiss-Italian border is the violet line on the top right. Based off the news reports, the approximate crash area is highlighted in red.

https://cimg6.ibsrv.net/gimg/pprune....c5dbc6dc2b.jpg
A very sad sight

I believe they found one survivor who spent many hours in sub zero temperatures. Did he not make it ?

With all that is known about the Robinson susceptibility to mast bumping in turbulence - why would you go flying in the mountains in 25 - 30 Kt winds???

Crab because they are invincible !

why would you go and fly a Robinson at all... 😥

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And once again your paranoia has showed itself, and off we go again with your same old ****e! ...

I'm accustomed to more astute observations from the usual posters. First the fuel cel red herring, lots of other helicopters didn't have them and they'd burn when crashed as did some that did, at any rate it didn't burn so nothing interesting there. Then the mast bumping based on what, wind? If there is some evidence the mast sheared I've been unable to find it. I'm more interested in weather and daylight and pilot. They departed at 16:00, sunset was at what, 17:20? Maybe dark sooner depending on cloud cover? 3000m is pretty high for an R44, but they weren't landing or taking off, and they were light. Just 'cause it was a Robbie isn't a reason to crash in itself. They are favoured by private owner/operators for cost though, similar to the Norway R44. Do we know any more about the pilot or the weather?

I don't think paranoia means what you think it means.

I am not anti-Robinson but we must acknowledge that very light blades are more sensitive to turbulence & mast bumping.
Heavy blades retain their plane of rotation long enough to handle sudden strong gusts.
But they require extra strength (heavy) laminations & spar at the root end to handle bending loads at the root (blade coning)

Frank came up with a good solution to save ounces and pounds in the rotor system
By incorporating coning hinges at the root which relieved any coning stress
Thus he could build very light blades .... which had the additional benefits of lower centrifugal force on the hub and feather bearings which meant he could build a lighter head.

Early blade de-laminations were the first red flag , but were attributed to outsourced blade manufacturing errors
Then came the numerous unexplained rotor incursions into the cabin or boom. A big red flag ... not to mention further de-laminations through the years

Easy for me to say ... but if he (stubborn frank) had halted production , built a blade similar to the H269 , strengthened the hub to take the extra loads , the problem would have been solved.

Of course those several pounds of weight would have reduced payload .... but extra pitch along with extra power from the de-rated engine should solve that ..... working the Lycoming a bit harder would likely reduce TBO from 2200 hrs to 1800 hrs which is still excellent for piston helicopters.

I am also suspicious of having 3 hinge points on a 2 blade rotor .... if a split second disturbance caused one blade to pivot on a coning hinge it would immediately put everything out of phase and would self-destruct.

I personally wouldn't fly a Robbie in mountains, time and time again we see this accident. It is obvious to me that when a Robbie is flown in mountainous terrain and it lands where it intended then the pilot got away with it and they didnt know how close to the edge they were. So they will do it again.

Its the wrong tool for the job, use a heli not susceptible to mast bumping if you want to fly over high hills or mountains.

No disrespect to people involved.

So no 205s, 212s, 214s, UH-1s in the hills either?

Think being aware of rotors and having wind limits makes sense, but avoiding mast bumping is about training and awareness.

And that is why there are a lot of Robbie accidents, esp R44: Low cost helicopter meets low experience pilot flying in a low discipline environment.

TT

I think this is the right way of putting it.

If you don’t, and if you fly a helicopter that is four or ten times more expensive, and if you bought your helicopter with your own money, then you would know why.

No, these models don't have the coning hinges in the head as Arnie Madsen describes above.

It may be that by design that Robbies are less tolerant to turbulence thaN the other 2-blade helicopters mentioned, but all can experience mast bumping. I think singling out the helicopter and not the more relevant factors in these accidents is the wrong focus. People just need to be more aware of the limitations of the aircraft. And particularly of their own.

How many other teetering head machines have speed warnings for turbulence in the manual?

Hahahahahaha! That literally made me laugh out loud! :)

On a more serious note, Robinsons are fine machines and clearly capable of being operated in mountainous terrain safely. And, yes, you do that in part by paying attention your speed in accordance with the POH and applicable Robinson Safety Notices, BR. My personal minimums tend more towards gust 25 for mountainous terrain, and I do try to respect the terrain in appropriate ways. But don't take my word for it. There are plenty of schools who teach mountain and high altitude operations in Robinsons. Youtube is full of those videos. You don't see Robinsons dropping from the sky like flies.

TT hit the nail squarely on the head: "Low cost helicopter meets low experience pilot flying in a low discipline environment." That statement could probably preface 90% of all Robinson accident reports.

@Torquetalk please confirm that by "low cost" your meant "more easily accessible and affordable" as opposed to "poorly designed or incapable"?

eta: this topic and this one are so similar you could probably combine them.

There ... you just hit the nail firmly on the head. In 25 years plus of following Robinson rotor issues this seems to be the view of a number of the worlds experts. The numerous unexplained Robinson rotor divergence issues are unique but so is the rotor head design with a teeter and 2 coning hinges. I’m sure this particular accident was due to being out in the wrong kind of weather and the result would have been the same regardless of what type of light helicopter was being flown. More frequent checks on the condition of the coning bolts and closely monitoring preload (resistance to movement) should be introduced. A Robinson operator told a story on here (PPrune) a couple of years ago of finding the broken off end of his coning bolt during a pre flight check in the hangar (a little alarming I know). I’m not a Robinson hater in any shape or form and would be willing to assist in any way I could reducing or solving this issue.


I am also suspicious of having 3 hinge points on a 2 blade rotor .... if a split second disturbance caused one blade to pivot on a coning hinge it would immediately put everything out of phase and would self-destruct.

You know, there used to be some cars whose engine would overheat when you drove them uphill with the air conditioning on. Some would whine that this was a design flaw and swear to never drive one of those cars,...others would just turn off the air conditioning, drive over the hill, then turn it back on.

I guess everyone just handles limitations in different ways.

Torquetalk The Bells have stronger components which may help in turbulent situations but you cannot tell me that using a Robbo in the Alps is not the wrong tool for the job. Also I dont think low experience of the pilot has anything to do with it, look at the accidents that have occurred in New Zealand over the years.

R44's are flown daily around the Alps without issue, because the pilots and companies that operate them do so safely by knowing the limitations of both the aircraft and the pilots. I think many of the posters trying to suggest that they are unsuitable for the environment simply haven't been here and don't have a clear idea of the helicopter operations in & around the Alps.

Although we have no idea what the cause of this incident was (and my personal hunch is that must bumping is unlikely to have been involved), the crash of G-RAMY on the Isle of Man in 2015 is a clear example that any semi-rigid/teetering rotor system is susceptible to mast bumping so we can all agree 3+ blades are best :).

Despite the satisfaction of pointing out the numerous shortcomings of the Robinson design, I think posts on this thread would be more constructive and worth everyone's while if they were related to the incident at hand and on the possible causes. Maybe this was whiteout/loss of references? Could icing have brought them down? Maybe the wind did cause the crash with a sudden downdraft when they were close to obstacles/ground? Hopefully there will be some lessons learned out of this one, and it's not just another repeat of last episode on 'R44 wreckage found in challenging terrain.'

Exactly. Another question might be how those bloody things were ever certified in the first place. Any other mass produced aircraft that doesn’t seen to be able to handle 35 knots?

I have flown an R22 in 35kts.

,...they can handle it just fine.

aa777888, I was simply talking about cost. The Robinsons are what they are and perfectly capable aircraft if flown properly.

The R22 is very light and there is very little energy in the main rotor and little authority margin in the tail rotor. It‘s a bit like a metal gnat. But gnats bounce of things harmlessly when they hit them, R22s don‘t.

The R44 is as different as it is similar. There is much more energy in the main rotor. R44s accidents are often performance related, with pilots clearly flying into situations which are just accidents waiting to happen. Many will have done a lot of autorotation training, but generally neglected the skills and knowledge needed to fly in performance limited situations. Exactly the kind of situations they are likely to find themselves in because it is a four seat helicopter, whilst training is generally done with 2 on board...

I have also flown an R22 in high winds, but I think you need to be very careful about when and where and why you would do this. Also had LTE through sheer niavety in an R22. Might have happened in other light types, but I reached and passed a limit very quickly in that case.

One of our fellow ppruners was killed ferrying an R22 back from Spain some years ago, encoutering CAT on the lee side of the Pyrenees in high winds causing the aircraft to break up mid-air. They clearly didn’t see that coming.

But Robinsons are not reasponsible for bad decsions to fly. At least one of the pilots involved was quite experienced in that case, but clearly failed to anticipate the danger. A counter example would be the Gazelle accident in NE England on a high wind day some years ago. In that case, it also involved a pilot flying in the lee of hills on a high wind day and completely lacking the skills and experience to be in or cope with the situation he put himself in. Nothing to do with the aircraft, he was just too cocky. Sadly not around to learn the lesson.

Good for you, so have I. However this is about the R44.

Not entirely John, the discussion has also encompassed criticism of Robinsons in general as being unsuitable for mountain flying by design and citing design as the main problem with Robinsons, as opposed to how they are sometimes flown. This discussion applies to all Robbies insofar as it‘s about people either flying an inappropriate design or poor airmanship being involved in many Robbie accidents.

I‘m in the poor airmanship camp.

Outstanding post, well said!

Thank you.

I disagree with the latter half of that statement. There is plenty of tail rotor authority in the 22, and the same for the 44 and 66. They all will work fine in a 30KN breeze. I'm told by other pilots they work fine in a 40KN breeze but that much wind is beyond my personal limits right now. Obviously one must fly carefully in such conditions.

A very good point. Similar to that being discussed in the other R44 crash thread. All that performance margin helps you survive training. Helps you right up until that very first flight with your newly minted pilot certificate and all the seats filled. I am very happy that the school I used intentionally included lessons at max. gross weight. The extra pressure and cat calls from the other students in the rear are also good training. Made another student airsick once as when it was my turn in the front the instructor had me performing "enhanced training in autorotation procedures", as SFAR 73 puts it. That was pretty funny!

What were the conditions when you had your "LTE" experience? Not to create a major thread drift, but a paper presented at the EASA Rotorcraft & VTOL Symposium 2019 entitled "The Myth of Losing Tail Rotor Effectiveness" makes some compelling arguments that there is no such thing as LTE and it is hard to refute the research. I have attached it to this post.

Thanks for another excellent post!

This seems to be more of an issue with schools who use the R44 exclusively. If you did your training in an R22 you'd be intimately familiar with flying at max gross weight and not being able to HOGE without busting power limits. An R44 with four on board is just an R22 with two. :8

That is a very good paper aa777888 :ok:

Everyone knows all 2 blade systems can experience mast bumping. Nothing new there.
But the R series has more than double the amount of others.
This was determined by an exhaustive study by NTSB and a high level aviation university
It was a true apple to apple comparison , nothing to do with number of machines sold or pilot experience.

NTSB nomenclature call it "loss of rotor control" or "blade incursion into cabin or boom"
And of course all of them also show mast bumping and broken droop tusks.

But my question has always been ..... what caused the initial loss of rotor control which caused all the other bumping-incursion damage ???

We all know about Zero-G ..... strong gusts ... updrafts ..... downdrafts ... equally applicable to all 2 blade systems .... with some advantage to heavy blades .... but can we blame the R failures on light blades alone ??? .... personally I dont think so.

I have always been suspicious of the 3 hinge points in the R system . It works as advertised and is a clever way to eliminate stress and bending at the blade roots. And at overhaul time mechanics will see wear at the main teeter pin and bushings (normal) and no wear at the coning hinge pins (good)

This indicates the coning hinges will only compensate for coning and pretty well remain fixed (no continuous movement-flapping in flight.) .... just as it was designed to do.

But what is to say that a rare aerodynamic situation could not occur that causes one blade to flap up on its coning hinge .... it would put the rotor system out of balance , plus without a lead-lag hinge a lot of stress on the (un-reinforced) blade root.

Other 2 blade rotor systems have a rigid head and are stiff and reinforced at the first few feet of each blade , thus the disturbance would be dampened and partly transferred to the other blade.

The R system is like a limp noodle by comparison with those 3 hinge points. And yes .... I realize centrifugal force tries to keep the coning hinges "stiff" but maybe a split second disturbance could alter that

I could be creating a monster that does not exist .... just trying to reason out why the R rotor experiences almost double the rotor incursions of other 2-bladers when all other circumstances are equal. (apples to apples )

Too add to that there is another unusual thing about the R rotor head.

ALL OTHER 2-blade systems connect the swash plate linkage to the blade pitch arm exactly at the teeter hinge position.

That way pitch is never altered when the rotor teeters, Pretty much an industry standard .

HOWEVER in the R system the pitch link is offset of main teeter point.

I could never wrap my head around how they get that to work



https://cimg9.ibsrv.net/gimg/pprune....9a450ca4fd.jpg

@crab thanks! There's also a Youtube video, but I found it superfluous after reading the paper. I just hope if the day ever comes when I let the **** get all spinny that I have the presence of mind to put the boot in and keep it there properly!

Every pilot has started to fly without experience. I think that it's not about experience, I think it's about discipline. I do know my limits, they depend on my experience on type, my recency, my overall experience, fatigue, stress etc.
If you know your limits and only fly missions within your personal flying envelope, you're professional
If you want to fly out of your personal flying envelope you are taking chances.
Experience doesn't change that. Experience expands your personal flying envelope but does not immunise you against accidents.

Arnie,
We use the offset pitch link system on model helicopters. It adds in negative feedback to the blade during gusty conditions. Imagine advancing blade flaps up but the pushrod from the swash plate holds the grip where it is, the result is the blade introduces momentary less pitch during the flapping (up) event and automatically twists the blade back down again at the same time. This happens for both teetering and flapping events when the pitch link is offset in this manner.

That video seemed less about disproving the existence of LTE and more about the pilots just not putting in enough left pedal to stop it. I think?,..I was having trouble following him.

Anyway, I remember once during my commercial training back in '06, while in a hover the instructor jammed in the right pedal and I was to react by chopping the throttle. I did, the yaw stopped and we set down.

I don't recall this guy mentioning that as an option?