Robinson helicopters added to safety watchlist

[skippers]

Robinson helicopters have been added to the Transport Accident Investigaton Commission (TAIC) safety watchlist.

The Robinson helicopters have been formally added to the Transport Accident Investigation Commission's (TAIC) official watchlist of "most pressing concerns".

The helicopters have been plagued by so-called mast-bumping incidents, in which the main rotor blades strike the cabin, causing the helicopter to break up in mid-air.

Fourteen such incidents have been investigated since 1996.

Commissioner Stephen Davies Howard said there was a real risk of further accidents.

"We are extremely concerned at the number of people dying as a result of Robinson helicopters crashing in New Zealand [and] we need to understand why."

People flying Robinson helicopters needed to be aware of TAIC's concern, he said.

"The commission is seeking a concerted action by the regulatory authorities, the manufacturer, operators, instructors and pilots, to promote the safe operation of Robinson helicopters."

Deaths place Robinson helicopters on watchlist | Radio New Zealand News (http://www.radionz.co.nz/news/national/316654/deaths-place-robinson-helicopters-on-watchlist)

Two more pressing concerns: Watchlist 2016 (http://taic.org.nz/Watchlist2016/TwomorepressingconcernsWatchlist2016/tabid/298/language/en-US/Default.aspx)

Still feel safe flying around in one??

[Thomas coupling]

Well well......smoke me a Kipper Skipper....who'd have thought that?

[Vertical Freedom]

I'm shocked NOT :ooh: about bloody time :mad:

[paco]

Is that only in NZ? What about the rest of the world? Private owners? Commercial pilots? Lack of training?

Heaven knows I'm not a big fan of Robbies, but I don't think they have more of a problem than any other brand in that respect. Or have they?

Phil

[212man]

Interesting definition of mast bumping - I always thought the clue was in the name!

[WillyPete]

212, it strikes the cabin after separation from the mast, incurring fatalities even at survivable heights.

[212man]

212, it strikes the cabin after separation from the mast, incurring fatalities even at survivable heights.

I find that hard to comprehend? Given that the condition results from a low g condition that requires reasonable airspeed and height to achieve, it's hard to imagine what height above the ground is considered 'survivable' for the occupants of a freefalling Robinson fuselage that was probably doing around 100 kts at the point of seperation?

[[email protected]]

And the Crapinson Flimsycopter is not exactly noted for its crashworthiness even when the rotors are still attached.

[DirtDiver]

Welcome to the G2 era ;)

[WillyPete]

I find that hard to comprehend? Given that the condition results from a low g condition that requires reasonable airspeed and height to achieve, it's hard to imagine what height above the ground is considered 'survivable' for the occupants of a freefalling Robinson fuselage that was probably doing around 100 kts at the point of seperation?

There's been other discussions on Robinsons and the teetering head in general, where someone posted the US military reports on the mast bumping phenomenon.
There was a training officer who survived one, but saw his copilot in the Cobra have his face severed by the departing blade.

A lot of those were occurring at terrain following, hence the low-g move as it crested hills.

Not saying this is the case with the noted Robinson accidents, but might be an argument used for this notice.

Also, not every "mast bump" causes separation before the cabin strike.
Example:
Robinson R66, ZK-IHU, Mast bump and in-flight break-up, Kaweka Range, 9 March 2013
Aviation Reports (http://www.taic.org.nz/ReportsandSafetyRecs/AviationReports/tabid/78/ctl/Detail/mid/482/InvNumber/2013-003/language/en-US/Default.aspx?SkinSrc=%5BG%5Dskins%2FtaicAviation%2Fskin_avia tion)
4.2.1.
There was clear evidence of a severe mast bump and that a main rotor blade had struck the cabin.
The main rotor drive shaft separated under a combination of bending, torsional and inertial effects, resulting from its being driven by the engine while the blades were prevented from turning because they had struck the fuselage.


It seems there's a few instances like this, with cabin strikes precipitating the loss of the rotor.
http://www.aaiu.ie/sites/default/files/report-attachments/2002-004%20EI-MAC_0.pdf
The flight from Weston to Sligo, via the Newtownmountkennedy area, was uneventful and routine up to 10:10 hours. Very shortly after this time an in-flight catastrophic event occurred resulting in the disintegration of the Perspex windscreen, as it was struck by the main rotor blades.
...
This event would have caused a critical loss of rotor RPM and very severe airframe vibration and loss of control, leading to the final impact. Pilot aided recovery would have been impossible after such airframe strikes. Finally, just before or during ground impact the main rotor struck the tail boom.


http://www.pprune.org/rotorheads/292551-r22-r44-rotor-cabin-rotor-tailboom-strike.html

[[email protected]]

212, it strikes the cabin after separation from the mast, incurring fatalities even at survivable heights. Willy - I don't think that is strictly true - the link you provided to the crash in Ireland states the rotor mast only fractured on impact with the ground - it is usually just the extreme flapping of the blades that gives the cabin/tail boom strikes.

There are reports that we have seen on this forum that show how the pitch change links and arms can be broken by the extreme flapping but the rotor head (what there is of it) can remain attached even during the blade strike process.

[Old Farang]

I do not want to get into arguing about the shortcomings or otherwise of Robinsons, as I am now too old to even clamber into one!

I owned one of the first R22s imported into Australia way back when ever it was. The serial number was under 200, so it did not have the tip weighted blades.

It was made VERY clear in the POH that low G maneuvers would very likely at least, result in the main rotor blades blowing back and cutting off the tail cone.

So it is not something new, and it is STILL caused by the pilot. And if the argument is that it can occur in turbulence, it is still a problem that a pilot has an option over.

Frank Robinson(and I have met him),never intended OR envisaged that the aircraft would ever be used for some of the hair brained operations that they are regularly used for.

And I also venture to say that there is probably a big number of pilots around today that would never have been able to afford paying for training themselves, if not for the cost effective use of R22s in those days.
In addition, once you mastered the twitchy things you would never have a problem transiting to bigger machines in the future.

[WillyPete]

Willy - I don't think that is strictly true

Yes, not the only cause. I probably should have led with the other quotes first.
It was the one that stood out to me when reading of the early lawsuits regarding the UH1 and cobra.


Frank Robinson(and I have met him),never intended OR envisaged that the aircraft would ever be used for some of the hair brained operations that they are regularly used for.

Yes, I don't think he imagined the amount of R22s used for herding in Australia, for example.

In all, I think it's probably just a step up in legislation from the SFAR issued by the US authorities.
The US might have done the same, if not been more restrictive, were it not a US export product, and the amount of schools that would suffer were they all grounded.

[pants on fire...]

So Volkswagen has to buy back hundreds of thousands of diesel vehicles because of an emission issue, but a helicopter that has killed hundreds of people just keeps on going?

Am I missing something here?

[aa777888]

Pants brings up an interesting analogy.

If Pants had said "Volkswagen has to buy back hundreds of thousands of diesel vehicles because the drivers keep crashing into other cars, into bridges, and in general losing control and killing themselves and others" then he'd have a point. But of course Volkswagen does not have to do that, nor does any other automobile manufacturer.

Similarly, some cars are much safer than others, both intrinsically (e.g. larger, more airbags, etc.) and demographically (e.g. purchased by older, wiser, more experienced drivers, vs. younger, more reckless drivers, etc.). Indeed, this link is quite interesting:

Driver death rates (http://www.iihs.org/iihs/topics/driver-death-rates)

Although sadly it does not distinguish between intrinsic safety and demographical effects.

As the saying goes, you pay your money and you take your chances. Some vehicles are intrinsically safer than other vehicles. Mixing it up with large trucks on a busy highway is much safer when you are driving a large SUV than when you are driving a motorcycle. Should we outlaw all motorcycles? Where do you draw the line?

When I arrived for my very first helicopter lesson I knew that the R22 was more challenging to fly and with less of a safety margin than anything that had a turbine and three or more main rotor blades. And, if I hadn't, the SFAR 73 safety lesson certainly made that clear. I assessed the risks and went on with it anyway. I could have decided to spend more money by learning in a Enstrom at twice the price, or even in a 206 at four times the price. I paid my money and took my chances, eyes open. No different than when I made the decision to purchase my first motorcycle (or, for that matter, when I decided to stop riding motorcycles).

So, where do we drawing the line? Perhaps we better start banning a whole bunch of much more dangerous stuff (like motorcycles), first, eh, before getting started on Robinsons?

OK, ready for massive holes to be poked in my analogy...

[PDR1]

but a helicopter that has killed hundreds of people

Hundreds? Really? All directly attributable to design/manufacture rather than the way they were maintained & flown?

PDR

[skippers]

I think the issue here is they don't no what is causing the mast bump in the first place.
Everyone knows that you should not do a low g pushover in a Robbie, but if a helicopter in level flight, in non turbulent conditions has a mast bump, what has caused it?

Quote from TAIC:
In the report, TAIC said there had been "many other fatal mast-bump accidents involving Robinson helicopters in New Zealand and around the world that have gone largely unexplained".

"It is difficult to identify the lessons from an accident and make meaningful recommendations to prevent similar accidents if the underlying causes cannot be determined," the report said.

[Gordy]

Not the first time this has come up:

NTSB Report on R-22 Accidents (https://app.ntsb.gov/doclib/safetystudies/SIR9603.pdf)

[[email protected]]

Skippers - the first few pages of the report Gordy links to start to give some reasons - the 'very responsive' rotor system, the unusual head design that allows the blades to flap independently and the unusual cyclic setup are all contributory factors.

Add in a great many inexperienced pilots flying the aircraft and you have a worrying mixture.

The stats for LOC (loss of control) accidents per flying hour are significantly higher for R22.

It does seem that flying too fast in a robbie can trigger events that result in similar outcomes to low G and turbulent conditions - makes me wonder if an excursion into retreating blade stall might prompt an inappropriate control response leading to the mast-bumping, tail strike and rotor separation sequence we are familiar with.

[Arm out the window]

I had flown mid-size turbines (mostly teetering head) for quite a few years previous to getting in a Robbie for the first time, and after a couple of hours getting used to things like the rapid spin-up of auto revs and a few other peculiarities like the T-bar cyclic, found them to be quite OK.

Been on them pretty much full time for the past 3 years doing all the whacky things you do when teaching CPL courses with low flying, autos from many different speed/height setups and so on, and I'll happily go out on a limb and say I quite like them.

They are built down to a weight and price, but when flown with respect and within their limits, and maintained properly, they're no more an accident waiting to happen than any other helicopter. They are responsive, manoeuvrable, quite good fun to fly and a great training platform for teaching students to think about power and wind.

Sure, they're power limited in some circumstances and can be overpitched, and you can't rule out mast bump with a teetering head - strangely enough just like the B model Iroqouis I did my helicopter training in, and you won't hear people bagging those out very often - it's more like reverence for the Huey (which I have my share of too!) but slagging off of the Robinsons even though they share quite similar characteristics in many respects.

[aa777888]

Not the first time this has come up:

NTSB Report on R-22 Accidents

Old news. SFAR 73 has changed things dramatically for the better since then.

https://disciplesofflight.com/sfar-73-a-rule-unlike-any-other-in-aviation/

More helicopters = more accidents.
More students = more accidents.

Least expensive to buy, least expensive to fly, and, one has to admit, leaving aside stability and margin, the R44 has an enviable set of performance characteristics. This puts a lot of such helicopters into operation by the least experienced segment of the pilot population, both student, recreational and "light" commercial.

Grounding the Robinson fleet would help the stat's because there would be a a) huge reduction in helicopter operations worldwide, and b) a large population of less experienced pilots would no longer be able to afford to fly. The same could be said of grounding every piston single airplane. Again, where do you want to draw the line?

Leaving aside military and retired military pilots, I imagine there are not that many professional pilots flying that did not come up through Robinsons, and would not have gotten where they are if it were not for Robinsons. Not saying everyone, but most everyone.

P.S. I know I'm chewing old, very old, ground here, and beating the proverbial dead horse down another molecular layer or two :ouch:, but maybe it's sometimes worth the review? If not, my apologies...

[Vertical Freedom]

& let us not forget:

Catastrophic Blade failures
Main Rotor blade delaminations
Infernos from survivable rollovers & prangs
InFlight swash-plate failures
:ugh:

The list can go on & on & on, but we know Frank build the greatest tragic Widow-Maker that ever flew :yuk:

[aa777888]

Widow-maker or not, greatest pilot-maker, too. It's a conundrum, no doubt about it!

It can happen to any design. The 225 seems to be the latest victim.

What matters is that they get better, not worse.

[CYHeli]

I thought I might share these as examples of when a pilot doesn't realise how close he came...
These are from a visiting machine and I only know part of the story.

http://i192.photobucket.com/albums/z275/colundy/IMG_1768_zps44hghht3.jpg
Tailboom on the drivers side. Both blades have touched the tail. Only paint removed, no actual indentation.

http://i192.photobucket.com/albums/z275/colundy/IMG_1782_zpstvkwcndl.jpg
My guess is that the aircraft was not in balance and so the tail has yawed forward to the left. As the retreating blade has flapped down, and the unload aircraft has rolled to the side... leaving the tailboom exposed to the flapping blade.

http://i192.photobucket.com/albums/z275/colundy/IMG_1778_zpsrnvzt6so.jpg
Note the upturned trailing edge. I'm not sure how much pitch was being pulled when the blade touched.

http://i192.photobucket.com/albums/z275/colundy/IMG_1777_zpsgce91bxm.jpg
Another view of the blade tip, trailing edge.

The upturned tip caused an out of track situation which was the first thing noticed by the pilot. A track and balance was later carried out.

There were no witness marks on the main rotor mast bump stops, so it makes me wonder in what order does stuff happen? Does the blade come into contact with the tail first then snap the mast, or as the mast snaps, does it contact the cabin...
The engineer inspected it all, found it within spec' and signed it off as safe to fly.
I think someone from the factory would love to see it to see what almost happened, although they are not likely to come to Australia.

[Arm out the window]

Do you happen to know the circumstances where those blade touches happened, CYHeli, e.g. running landing, practice stuck pedal, torque/pedal reversal turns or anything like that?

I've seen one that whacked a blade on the tailboom after someone ran it on into soft sand, probably with low RPM at the time.

[CYHeli]

Basic story of one up, flying through turbulence. The pilot likes to brag and was describing 40kt winds. But it was at least 30. I know that he is also not one to slow down often.

[aa777888]

...very scary photos...

:ooh: holy cr@p!!!

Basic story of one up, flying through turbulence. The pilot likes to brag and was describing 40kt winds. But it was at least 30. I know that he is also not one to slow down often.

http://www.robinsonheli.com/service_library/safety_notices/rhc_sn32.pdf

:=

Thanks for posting that, CYHeli.

[SASless]

Every time I see a Robbie....of any description...I hit the nearest Burger Bar and order up a Double Burger, Large French Fries, and Chocolate Shake. If I cannot get into the thing then I have a lot less worry about one of them killing me.

The Burgers and Fries might...but at least it will take decades to do it.

[malabo]

Meet the Charity Training Future North Sea Pilots - Oil and Gas News (http://www.oilandgaspeople.com/news/10314/meet-the-charity-training-future-north-sea-pilots/)

Most safety conscious helicopter company in the world picked what helicopter to train North Sea pilots?

[bgbazz]

malabo

Their choice of helicopter might be questionable....but their motives are certainly not.

SASless

After numerous hours chasing cows and camels in them, I share your sentiments...stick with the burgers, mate...a much nicer way to go.
What I really meant to say was...I'd much prefer to be eating one, than being one!!

[SASless]

Most safety conscious Helicopter Company in the World....as more than few of us are alumni of that illustrious concern.....you might find it a very cold room to play if you intend to peddle that notion here.

I am assuming it is that small outfit that shifted its HQ from Redhill to Houston to which you are referring.

[megan]

What market segment was Frank chasing when he designed the R-22? Chap here says "It wasn't designed as a trainer and it isn't a very good or very safe trainer".

Robinson R22 (with some comparisons to the R44) (http://philip.greenspun.com/flying/robinson-r22)

One source says of 4620 R-22 built, at the time the stats were compiled in June 2010, there had been 182 fatal accidents from a total of 1230 accidents. 27% accident rate. :sad:

Although the offer was made by an FOI, refused to go for a ride in one many years ago.

[aa777888]

One source says of 4620 R-22 built, at the time the stats were compiled in June 2010, there had been 182 fatal accidents from a total of 1230 accidents. 27% accident rate.

The early years weigh heavily on the overall stat's. Per wikipedia: "...after the introduction of the Robinson Pilot Safety Course, the rate of fatal R22 accidents declined from 3.7 per 100,000 flight hours in 1983 to 0.97 per 100,000 flight hours for the 12 months preceding July 1995. Robinson’s statistics show the rate of fatal R22 accidents per 100,000 flight hours fell from 6.0 in 1982 to 0.7 in 1997."

Things are much improved now that people have a better handle on how to fly them, instruct in them, maintain them, and now that Robinson has made some improvements to the design.

As long as they remain legal people will fly the heck out of them because they are least expensive certificated helicopters to own and to fly. The lure of the sky is strong, as we all know, and generally stronger than the desire to be as safe as possible. For all of you lucky enough to be able to learn in more expensive equipment, or in the military, more power to you. For the rest of us clearly the trade-off is worth it or we wouldn't do it. And, I suspect, the idea of grounding the Robinson fleet would be seen as usurping the right to judge risk for one's self by nearly the entire population of Robinson pilots and operators.

It's interesting where people draw the line at the assumption of personal risk, particularly when money is involved. I live in a place where neither seat belts nor motorcycle helmets are required. I like that. I like that a lot. I like such personal freedom. And yet I wear both. But, obviously, I do fly Robinsons. However, I suspect that if seat belts cost $10,000/year, I might not wear them!

[tartare]

Jaysus.
1.6 secs to drop the collective...:eek:

[Tarq57]

1.6 seconds.
So that's why, during my 3 flying lessons in one, when we had a go at autos the instructor simulated them by just lowering the collective, rather than winding off the throttle.

[skippers]

Another one down....

From Stuff.co.nz

The bodies of two people have been found among the wreckage of a commercial helicopter that crashed in Northland's Glenbervie Forest.
The two people that died in a helicopter crash were doing surveying work over a Northland forest, timber harvesting company Rayonier said.

Rayonier's managing director Paul Nicholls said the two employees were contract
Emergency services scrambled to respond to the helicopter crash on Monday afternoon.
They were doing survey work and possibly aerial spraying over Glenbervie Forest near Hikurangi on Monday, Nicholls said.

The wreckage of their chopper, a Robinson R44, was found about 2pm.

READ MORE: Rail crossings and Robinson helicopters added to list of nation's biggest safety concerns

Police said the bodies of two people were located at the scene.

"Police are now working to identify the deceased and notify next of kin."

Emergency services rushed to the forest after an emergency beacon was activated just after 1pm. It was activated off Lookout Rd, in a heavily forested area about 20km northeast of Whangarei.



Nicholls said the company was "yet to actually confirm what [the helicopter] was doing immediately prior to the accident".

"Unfortunately we don't have a lot of detail at the minute. We don't have any clear idea of what happened. Our concern at this stage is with the families - we're pretty distressed as are the family members."

Rayonier manages the land where the helicopter crashed.

Ange Vivian, the company's general manager of support, said earlier on Monday the incident was "really serious".

"Staff from [the] Northland operation are assisting. The coverage in that area is really bad, [we're] just waiting to hear more details."

Robinson helicopters, which make up 40 per cent of the nation's chopper fleet, were last week added to a Transport Accident Investigation Commission watchlist of serious transport concerns.

On Monday night the commission said it "will not speculate or comment on any potential relationship between this afternoon's accident and its Watchlist item concerning Robinson helicopters released last week".

It said it was monitoring the Civil Aviation Authority's investigation into the crash to see whether the circumstances may warrant a separate inquiry by the commission.

"The commission opens an inquiry when it believes the circumstance may have significant implications for transport safety or allow new findings or recommendations which may increase safety," it said.

In its watchlist mentioning the Robinson helicopters it cited the potential for "mast bump".

Mast bump is contact between an inner part of the main rotor blade and the main rotor drive shaft atop the fuselage, otherwise known as the mast.

It has happened 14 times since 1996, claiming the lives of 18 people.

The incidents have raised concerns about the risks of flying Robinson helicopters in mountainous terrain and strong winds.

The outcome is usually catastrophic with the helicopter breaking up in-flight, transport accident commissioner Davies Howard said.

[aa777888]

According to the FAA accident database, in the USA, calendar year 2016 to date, there are 89 helicopter accident entries so far (not including home-builts). It breaks down as follows:

Make (all types), # accidents, # total fatalities

Airbus/Eurocopter, 10, 5
Hughes/MD, 12, 2
Robinson, 24, 4
Bell, 33, 12
All other makes, 10, 4

Now without knowing the total hours flown by each make, it's not a very good set of stat's. However, is it reasonable to assume that training activities, meaning Robinsons, account for most of the hours flown annually by all helicopters?

[Vertical Freedom]

Hoy CYHeli - G'Day Mate scary :ooh: but turbulence flying will never cause such problems in any machine but in a Crapinson :eek:

After more the 4,500hrs flogging around in a JetBanger above 10,000' in eXtreme turbulence, with updrafts, downdrafts, swirling & 50++knots of wind; I never once came close to 'mast-bumping' or the Tail-Rotor-Blades' kissing the boom......Cheeezus that's seriously F.ing scary, welcome to the Flimsicopter range of death traps, build to break-up & crash :yuk:

[aa777888]

That's not fair, VF. "Built to break up and crash"--IF you exceed the POH limitations and guidance. Same could be said of LTE on Jetbangers. Same could be said of exceeding POH limits and guidance on ANY machine.

Clearly, not as capable machine in turbulence, the Robinson, the documentation says so, the training says so, so don't ignore either one!

[Vertical Freedom]

Hey aa777888 this ain't about fair, just hard facts....:mad: tell your story to Ivor or at least another 3 good Men that I personally knew all killed whilst operating well within the RFM limits & being correctly maintained.....but the Crapinson loves to break-up in flight :{ yep the Jettie can have LTE, I've induced unintentionally it at least thrice :ouch:

[[email protected]]

Are any other helicopters the subject of a SFAR like the robbie? Do any other helicopters have such fatal vices (even when inside the flight envelope)? Are any other helicopters having unexplained breakups in mid-air?

I understand the appeal of a cheap trainer (not what it was designed for) but letting low-time pilots (post PPLH) out in this thing is inviting problems. How much flight at Vne or close to it is actually covered in the PPLH syllabus - is it one of those things that is just talked about all the way to CFI level as part of the SFAR 73 awareness training or is it physically taught?

[WillyPete]

How much flight at Vne or close to it is actually covered in the PPLH syllabus

Hitting Vne is incredibly easy on the R22.
Basically you just have to not pay attention.

On the Cabri I find I'm slowing down when I'm focussing on something like radio work or navigation. You have to "intend" to get to cruising speed, 70-80.

[aa777888]

VF--I'm very sorry to read of the deaths of those good pilots. However many other helicopter types have had design-related fatalities, and many of those resulting in airworthiness directives, the venerable JetRanger being no exception.

Crab--I'm sure your SFAR question was rhetorical, but while not a helicopter, off the top of my head there is at least the MU-2 SFAR, so the Robinson is not entirely unique among all types of aircraft. And certainly other helicopters have other vices. Jetranger LTE and Squirrel landings both come to mind and both have resulted in poor outcomes. There surely must be other examples.

I can't speak for other students, but I have received specific instruction on Vne limits, turbulence, and low-G conditions, and have operated the 22 and 44 at or near Vne many times in instructional settings. Personally, I don't feel comfortable in winds over 25KN, nor with gust spreads much over 10KN. There is ample opportunity to train in turbulence here, with New England mountain ranges in close proximity, and I have availed myself of that opportunity.

In a three dimensional cost/performance/safety trade-off, it's pretty clear that civilian pilots, whether they be budding professionals, purely recreational, or what might be termed "light" commercial, are willing to trade off the safety dimension. The siren song of low cost with, particularly in the case of the 44, good performance, is extremely strong. For those who's choice is don't fly vs. fly Robinson, you know how all those pilots are going to choose, because pilots want to fly.

[Lonewolf_50]

One source says of 4620 R-22 built, at the time the stats were compiled in June 2010, there had been 182 fatal accidents from a total of 1230 accidents. 27% accident rate. :sad:
@Megan: accident rates are typically broken down by hours flown, not by number built. (I would think that you'd know better).

[skippers]

Glad to see this is getting some traction. Might be a few used 44's going cheap soon...

Robinson Helicopter "unsafe and unairworthy"
Interesting audio from a US lawyer regarding Robinsons:

Radio New Zealand Audio Player (http://www.radionz.co.nz/audio/player?audio_id=201822025)

[megan]

Megan: accident rates are typically broken down by hours flown, not by number built. (I would think that you'd know better)Know exactly what you are saying Lonewolf, but certain aircraft earn a reputation, look up the German experience with the F-104 for example.

We might ask the question if the "accidents" mentioned were just of the bent crosstube variety, or write offs. I may err by assuming the latter, which despite hours flown, would seem to me to be just a tad on the high side. Just a tad mind you.

[CYHeli]

Article - is-there-a-problem-with-Robinson-helicopters (http://www.stuff.co.nz/national/85930635/is-there-a-problem-with-robinson-helicopters)

[Frying Pan]

The other common denominator appears to be New Zealand. Is it their training or their environment? Or both? I don't know the answer. Others will know, no doubt.

[skippers]

I think there is a common belief that it is only in nz that this is happening, but if you look into the world wide stats you will find Robinson helicopters have broken apart mid flight all over the world...
Other than fitting a camera to every Robbie and waiting for another one to crash, how will they ever no what is causing these in flight break ups?

[Nescafe]

New Zealand Helicopter Survey (http://www.aia.org.nz/site/aianz/2016%20New%20Zealand%20Helicopter%20Survey%20Results%20(1).p df)

Some interesting stats which may reflect on how Robbies are operated in Un Zud.

[Frying Pan]

Interesting survey indeed. From the land of adrenalin sports appears a similar approach to helicopter flying. Of course that's a huge generalisation as any particular flight school in NZ, I imagine, will gladly clarify.

[Octane]

Very interesting survey. Would be interesting to read responses for same in other countries....

[Hughesy]

Good old Kiwi bashing, always comes out.
I guess there is never any accidents/incidents or machine failure anywhere else in the world other then New Zealand.
Another 44 has gone down. Another family has lost a father, husband, son, brother.

[vaqueroaero]

I have often wondered why there has never been an indicator fitted that will register an exceedance in manifold pressure, even if it only indicated an exceedance of the red line. I'm involved in ag work and regularly talk with pilots that claim that their 44's will carry as much product as a 206. When you ask about manifold pressure limits they change the subject...

[aa777888]

Article - is-there-a-problem-with-Robinson-helicopters:
(http://www.stuff.co.nz/national/85930635/is-there-a-problem-with-robinson-helicopters)
"The rate of "low-G" accidents involving Robinsons is significantly higher in New Zealand than in other parts of the world - about nine times higher than the US, according to the Transport Accident Investigation Commission (TAIC)."

That's a pretty amazing statistic, if true.

[[email protected]]

Good old Kiwi bashing, always comes out. that seems like a very defensive reponse.

The survey would seem to suggest there it is far more to worry about than Kiwi-bashing.

[Hughesy]

Not defensive at all. Well maybe a little. I just get sick and tired of all kiwis being tarred with the same brush when it comes to flying. the majority us fly professionally, and have high standards. Like the majority of pilots in other areas of the world.

[Frying Pan]

it's no more tarring a brush than say locals flying 139s in Africa. But there is a pattern. Of course the majority of pilots are professional and live by high standards but there is a disproportionate amount of stats pointing a finger at NZ. Is it the inherent risk taking, which is taken for granted? Is it the commercial pressure, too many pilots, too much government grant, people willing to please and get paid peanuts?

[Lonewolf_50]

@megan: roger, and sorry if my response came off as a bit snarky. Reading it and your reply, I think my tone could have been better. Mea culpa. I get your point on aircraft having reputations.

[krypton_john]

NZ is a sliver of mountainous terrain between two oceans and most areas in NZ are subject to gusty winds and turbulence a lot of the time. So there's a lot of flying by Robinsons in a gusty, turbulent mountainous environment.

So maybe instead of comparing NZ to say, all of USA, it would be interesting to compare NZ to Washington State for example?

[SASless]

I have some knowledge of Washington State and the levels of turbulence One can encounter there particularly in the Mountains.

One particular flight during a Frontal Passage which took me east of Seattle in the vicinity of the Snoqualamie Pass where the Interstate Highway crosses the Cascade Mountains....was a genuine experience.

Fortunately I was in a Hughes 500E....and it made for a very uncomfortable ride....one I did not wish to take but did so as a teaching point to my Corporate Passengers. I had told them it would be very rough but within the capabilities of the aircraft and mine as a Pilot but I felt it would not be advisable to go. That was a "No!" but as they had gotten into the old game of trying to argue about such a decision I felt it was time for a lesson on why Pilots sometimes utter that horrible word to them.

They insisted they just had to go by air notwithstanding my explanation for why that was not a wise thing to do....and we set out to cross the mountains.

We did not succeed and only after they realized I in fact knew what I was talking about....agreed to land at a Truck Stop and have their meeting at that location instead of the Saw Mill to which we were headed.

They never challenged a "NO!" after that.

A Robbie would never have survived that level of Turbulence.

Every aircraft has its limitation as does the Pilot flying it.

I would not have considered doing that same flight in a Jet Ranger either....and probably not even a Huey.

I have a lot more faith in Articulated or Rigid Rotor type Rotor Systems than I do the Two bladed Mast type systems used by Robinson and Bell when it comes to Turbulence. It is one thing to hear Droop Stops pounding in flight as compared to Mast Bumping.

[newfieboy]

Absolutely spot on SAS, I've flown in some nasty turbulence up here in The Great White North in 500D,E, 520N and AS350. The kind of stuff I wouldn't go near in a 206/L, 205,212 let alone a R22/44/66. Called it earlier this year on a drill camp due to severe winds and turbulence flying an LR 3 model, apart from that was it was a nice day. No one on camp had a problem, I certainly didn't, nor the Boss.::ok:

[Gordy]

I will add to SASless and Newfie's comments.

All my staff are required to complete a point based "Flight Risk Assessment", (FRaT), as I am sure are most of you.

When saying "No", wee pull out the FRaT and explain the basic concept of SMS and FRaT to our passengers. We have NEVER been questioned once we started this process.

[KiwiNedNZ]

I would say now that the R44/R66 makes up the majority of the piston engine fleet in NZ. It gets used for everything, from flight training, to ag work, to utility work etc, and even a few machines still doing venison so if something is going to happen in our industry then more often than not its prob going to involved a Robbie of some description. Not sure of the actual stats but wouldn't be surprised if Robbie products accounted for close to 50% of our industry.

[[email protected]]

HOW FREQUENTLY RESPONDENTS THOUGHT THESE HAPPENED
Frequently Sometimes Rarely Never
Performance limitations are exceeded 13% (76) 49% (289) 29% (170) 9% (51)
Operators cut corners and take shortcuts 8% (48) 42% (242) 38% (220) 11% (63)
Safety considerations come second 8% (47) 26% (153) 35% (203) 30% (175)
Pilots are susceptible to peer pressure 10% (57) 43% (247) 35% (201) 13% (75)

Just the one line about 49% admitting that performance limitations are exceeded 'sometimes' is scary enough

[KiwiNedNZ]

Crab - But with these answers are the respondents admitting that this is what they do, or is the answer to the question their thoughts about the rest of the industry doing that ?

[Thewasp]

Saw one routinely thrashed by a chief pilot, I walked out the door of the shambolic outfit and reported what was going on, they did nothing of course but at least my conscience would be clear if something happened/happens

[[email protected]]

I think that's your answer Ned.

Generally people are a little conservative when admitting wrongdoing so the real figure may be much higher.

[Baldegret]

Gordy, I'd be interested to see an example of a FRaT. Sounds like something us private pilots could usefully adapt and adopt.

[Thewasp]

I will add to SASless and Newfie's comments.

All my staff are required to complete a point based "Flight Risk Assessment", (FRaT), as I am sure are most of you.

When saying "No", wee pull out the FRaT and explain the basic concept of SMS and FRaT to our passengers. We have NEVER been questioned once we started this process.

That's great when everyone is on board, we do it too, clients never seem to question it, some other local operators that are so hungry for the revenue plus keeping their egos topped up would never take it on

[212man]

Gordy, I'd be interested to see an example of a FRaT. Sounds like something us private pilots could usefully adapt and adopt.
Here's one example: https://www.faa.gov/news/safety_briefing/2015/media/SE_Topic_15-08.pdf

Here's the guide to the HAI one - the online version requires membership to register for, but this guide shows the questions and scores, so lends itself to creating a personal spreadsheet:
https://www.rotor.org/fox/mission/hai_mra.pdf

Comprehensive excel version here from EASA/EHEST, with tabs for different types of operations (HEMS, CAT, SP vs MP etc)
http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjurLyDw4zQAhUHnRoKHeKkD7sQFggbMAA&url=http%3A%2F%2Fessi.easa.europa.eu%2Fehest%2Fwp-content%2Fuploads%2F2012%2F06%2FEHEST-Pre-departure-check-list-V15.xls&usg=AFQjCNFO7ejlfrtEERs-rbLUyzGdNJyWww

[Baldegret]

Thanks 212Man. Interesting reading.

[RVDT]

Two New Zealand organizations suspend use of Robinson helicopters (http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11740646)

DoC (Department of Conservation) would be a large part of a lot of commercial operators work in NZ.

Looks like they have made a conscience decision and it may seriously curtail the viability of Robinson products there. As they say a lot of people will be "squealing" with this decision and some maybe not.

Legality should never be confused with safety. Good call - finally.

[rotorfossil]

The problem in NZ is more to do with the operating culture as the Robinsons. Two instances observed while we were flying around NZ. Pilot pushed R22 onto the pan, stuck his head into the cockpit, started the engine engaged the rotor then wandered off leaving the Robbie to wind itself up. Returned a few minutes later with his coffee, climbed in and took off. Second. Two large gentleman, one with a rifle, took off in an R22 carrying a net. Asking what was going on, it was explained that this was a deer culling job. Shooter kills the deer, puts deer in net, then R22 lifts crew, plus deer to clear area. A quick sum means that this would be so far in excess of max AUW to be ridiculous.

[[email protected]]

Not exactly a professional approach to aviation in those two situations - would be interesting to know just how common that sort of thing is and it puts the 49% of 'sometimes' performance exceedences into sharp focus.

[megan]

A quick sum means that this would be so far in excess of max AUW to be ridiculousA NZ technique for sling loading deer carcases out was to position the load next to a drop off, the Robby being unable to hover with the load would pull the load off the ledge, dive into the valley to get bucket speed, and Bob's your uncle.

[Hughes500]

Megan

WTF Well if it doesn't hover with the load that is telling you something. While we all try and move forward to break the inertia of a load that technique is going to snatch on the airframe and send a shock through the drive system, great for longterm survivability !:ugh:

[whoknows idont]

A NZ technique for sling loading deer carcases out was to position the load next to a drop off, the Robby being unable to hover with the load would pull the load off the ledge, dive into the valley to get bucket speed, and Bob's your uncle.

The prosecution has no further questions.

[212man]

Megan

WTF Well if it doesn't hover with the load that is telling you something. While we all try and move forward to break the inertia of a load that technique is going to snatch on the airframe and send a shock through the drive system, great for longterm survivability !:ugh:
I don't think he is condoning it!

[JohnDixson]

Sounds like a version of the venerable ( ? ) Wenatchee Snatch from western US logging has migrated to NZ. That sort of technique and the associated structural/fatigue loads is of course not reflected in the manufacturers original flight load survey test conditions, therefore those flight loads and the associated load usage spectrum used to compute component replacement times goes out the window.

[Old Farang]

A NZ technique for sling loading deer carcases out was to position the load next to a drop off, the Robby being unable to hover with the load would pull the load off the ledge, dive into the valley to get bucket speed, and Bob's your uncle.
That "technique" has been in use as far back as using Hillers. Dick Deaker has over 20,000 hours doing it without a problem. Not condoning it, but the loads are usually slung off a few thousand feet above where they are landed.

As a former R22 owner(not in NZ) there is no way I would attempt it in a Robinson though. There are several clips on YouTube, both of Dick in a H500, and an R22 showing the complete operation by someone else.

[WillyPete]

Deaker:
https://www.youtube.com/watch?v=6wbJSS8Gzvc

Considering the terrain the NZ guys operate in, I'm not surprised they hit turbulence.
(Warning: hunting and some blood)
https://www.youtube.com/watch?v=xo_7HP3bkIY
https://www.youtube.com/watch?v=0Xmg45cHEPQ

[212man]

https://www.youtube.com/watch?v=0Xmg45cHEPQ

Animals still clearly alive at 2:06 and 4:00!

[Hughes500]

well at 5:20 in the second clip if that is not a snatch which shock loads everything I don't know what is. Not sure an R22 is built for that abuse. I would love to know how heavy the guys are plus the deer and how much fuel, would bet a lot that it is over MAUW

[[email protected]]

It's just f888ing appalling that these guys even have licences - do they even look at the RFM for performance before they get airborne on this sort of thing.

If this habitual exceedence of performance is widespread in NZ, no wonder there are concerns.

But in this case, don't blame the Robinsons, blame the idiots flying them. It's a helicopter, not a truck!

[Hughes500]

I think I need glasses as in the last clip I could have sworn the MP was over max a few times, then again I have just acquired my first set of glasses, perhaps it is an age thing ?

[megan]

Hughes500, I've never flown in NZ, and the only deer I've seen in the flesh have been prancing about on four legs.

[Hughes500]

Megan

Calm down never implied you had and my apologies if that is how it came across

[megan]

Hughes, if I were any calmer I'd probably be pronounced "dead". Trouble with the written word is the belief that communication has taken place. Made the post in light of 212man's comment, just to avoid any misapprehension.

[CYHeli]

Is it time to bring out articles like this to help pilots?
Rotor Torque Spring 2013 Martin and Simon. (http://www.morningtonsanfordaviation.com/pdfs/Rotor-Torque-Spring-2013-Martin-and-Simon.pdf)
I think the level of education is better is some places than others.

[[email protected]]

CY - that is an excellent article, which was clearly difficult to write for the author, but it brings out valuable lessons for pilots of all levels of ability and experience.

Military FS courses cover all those lessons and more, shame they aren't available to non-mil.

[FLY 7]

Is it time to bring out articles like this to help pilots?
Rotor Torque Spring 2013 Martin and Simon.
I think the level of education is better is some places than others.


I was never sure about that article. It attributes some justified blame, but is quite protective of the helicopter's design issues.

[Hughes500]

Fly

What do you expect tricky dicky thinks they are the best thing since sliced bread !

[[email protected]]

Perhaps it would have been more balanced to add that pretty much any other helicopter in the world wouldn't have broken up in those conditions - might have been uncomfortable - but not fatal.

[vaqueroaero]

I have a book called the The Chopper Boys and The Helicopter Hunters, written by Rex Forrester ISBN 0143018493 which is an account of the mayhem and anarchy of deer hunting in New Zealand 'back in the day'.

It's a very interesting read to say the least.

Just looked it up on Amazon, I had no idea it was worth what it is....

[TTSN]

I was never sure about that article. It attributes some justified blame, but is quite protective of the helicopter's design issues.
Totally agree, the author of the report is far too close to Robinson to be objective about the design limitations of the aircraft. I'll except all the advice given in his detailed report but I can't help but feel there is an elephant in the room in relation to not mentioning the quite severe limitations caused by the rotor system design, in nearly all cases accidents seem to be concluded as the pilots fault. A design that requires a special pair of kid gloves to operate quite simply isn't the best design for that application. Endless special training and warnings about how they have to be flown is just circumnavigating a huge problem that is always there.

[Bell_ringer]

What I have often wondered is why Robinson seems to be doing so little to improve the rotor system? From articles written it would seem that little modern CFD analysis has been done to look at unexpected behavior.
Blaming pilots seems to be a get out of jail free card and perhaps starting to look deeper into the situation would almost appear like wrongdoing (The Trumparians do like to litigate).

The many iterations of blade design (and they don't seem to have perfected it) poses some questions about the state of their engineering and quality control and at the very least indicates some work is needed.

Too many good people have died in seemingly straight and level flight and placing the blame solely on the individual and not the machine seems misplaced.

The 66 is continuing the trend, possibly helped by the additional power, so it really is time to start doing something about it.

This isn't about knocking the machine, there is no denying it's contribution to rotorwing ops, training and making helo flying affordable and accessible.

[WillyPete]

What I have often wondered is why Robinson seems to be doing so little to improve the rotor system?

They can't make any changes.
Anything requiring recertification would likely mean that the aircraft would fail certification completely under current standards.

[Birdy2]

Iv asked this question on other forums without a responce, could someone here help please?

Interested to know, if someone can help, some head limits on Robbies.
How much stop to stop teetering range ( degrees) on the 22,44 and how much cyclic range, fore n aft, right to left?
Thanks in adavance.

[FlimsyFan]

They can't make any changes.
Anything requiring recertification would likely mean that the aircraft would fail certification completely under current standards.
I'm disinclined to agree with you on that. The R66 was certified (relatively) recently, and as a completely new airframe had to undertake full certification rather than a modification / amendment to an existing one. If any of the certification requirements have changed since then, I'm not aware of it.

I think in the near future we will see development of a 3 or 4 bladed rotor system, certainly on the R66. This is something I was told directly by RHC that is now being looked at with some commitment.

As an R66 owner / operator, I am concerned about the in-flight break up issues. Attendance of the RHC Safety Course has certainly further increased the awareness of the causes of mast bumping, and must admit that when the machine is light (solo, under 60% fuel), I tend to fly around at 100kts IAS, which in the flatlands of the Midlands is probably very over cautious.

I love the machine to fly, and whilst acknowledging the risks, accept the responsibility to treat it extremely sympathetically in many circumstances to ensure its safety. I do, however, understand why so many people are quick to knock the Robbos, but ultimately, I guess you pays your money and takes your choice.

[Thomas coupling]

Dick Deaker - clue's in the name I s'pose.
To be honest, there's a bit of me in that flying but common sense has to prvail because I have responsibilities in life, to my family and to the people who work with and around me.
Flying like Dick in that video is great and exhilarating until of course it goes wrong. The NZ CAA must struggle to police activities like this....
But Robbo's make evolutions like this - much more financially viable so in a way, Robbo's exacerbate the problem. Then you throw in their fragility and voila, the perfect recipe for disaster.

One has to either be desperate for work, or not value one's life much to fly this way in the end.

Great fun - but, alas, those days are over for most of us.:hmm:

[[email protected]]

Interested to know, if someone can help, some head limits on Robbies.
How much stop to stop teetering range ( degrees) on the 22,44 and how much cyclic range, fore n aft, right to left?
Thanks in adavance Not sure why you would want that information Birdy - there is no problem with control authority or cyclic response on the Robbie (quite the opposite).

The teetering range is not the same as the flapping range as the hinges are separate and mostly independent of each other.

[WillyPete]

It's a much more modern machine though, flimsy.
I agree with you on why people knock them.
I thought it an incredibly agile and responsive machine (possibly leading to people thinking they can throw it around) and agree that responsible piloting would be the answer to the problem.
As it is, it's simply too unforgiving if it is really striking the cabin as frequently as articles indicate.

[Birdy2]

Not sure why you would want that information Birdy
Working on a hunch Crab.
I know the configuration of the Robbi head, i just need the specs.
I also know theres ample control authority......... .

[JohnDixson]

This NTSB Report:

http://www.rotorshop.com/sir9603.pdf

Makes for interesting but sobering reading and does mention a teetering limit at +/- 12 degrees. No detailed drawing of the head.

Good reading for any DER's in the audience.

[Hot and Hi]

I was never sure about that article. It attributes some justified blame, but is quite protective of the helicopter's design issues.
True. But that aside, with the greatest respect for Richard based on his other work that I am aware of, and with due respect for Martin who if nothing else was a highly qualified, experienced and accomplished competition pilot, I don't know quite what to do with Richard's advice.

Many of the things that Richard identifies (like peer pressure, get-there-ites, scud running, mental expectancy, suckers gap) helicopter pilots around the world experience or do frequently. This is the nature of the game. Else we would be like microlight pilots who only ever venture to the sky in the early hours of the morning, or just before sunset on a picture perfect day. The client wants to leave as late as possible (to get home before dark), and then still eats by 30 min into our buffer time; the clouds are low but we get through; the pax are definitely heavier than declared; the 'hand-luggage' of the paramedic is a 50 lbs heavy equipment bag; ... the list goes on.

The question is not where it starts (as we cannot avoid it in real life) but where to draw the line.

The Robbie flies perfectly well in 40 kts winds. It deals well with mild to moderate turbulence (giving time and opportunity if encountering the latter to fly out of it). +15 kts gusts are seemingly a non event. With very good tail rotor authority you can handle strong crosswinds in the hover. It is highly responsive allowing the pilot to handle any rotors or turbulences that I have ever seen, created by buildings or other structures along the approach path.

So where to draw the line? As Richard points out, none of the pilots who experienced inflight break-up of their helicopter, took off with the intention to die today. How do I know that turbulence is "light to moderate" (and not "moderate to severe", which Robinson disallows)? And are we saying that all those who crashed after encountering turbulence, have done so because they pushed on in conditions of severe turbulence, failed to reduce airspeed, and/or gave incorrect, hamfisted cyclic inputs?

Somebody please tell me. Richard's article is silent about this.

[rotormatic]

Robinson adding new yellow arc on airspeed indicator:

http://www.robinsonhelicopter.com/service_library/r66_service_bulletins/r66_sb19.pdf

[Octane]

I just read the NTSB report. I'm not an aviator. My interpretation of the report indicates the NTSB could not in the end actually determine why the the rotor failures occurred in most of the accidents, particularly with the aircraft that were operating in normal flight conditions.
Is this correct? Disturbing if so...

[aa777888]

I just read the NTSB report. I'm not an aviator. My interpretation of the report indicates the NTSB could not in the end actually determine why the the rotor failures occurred in most of the accidents, particularly with the aircraft that were operating in normal flight conditions.
Is this correct? Disturbing if so...

On the other hand, since SFAR 73 took effect in the US, there have been very few "unexplainable" events, in the US at any rate. This would seem to imply that with heightened attention on low G and low rotor RPM recognition the vast majority of R22/R44 issues have been resolved.

On the other, other hand, as one of those people who must make a choice between flying Robinson or not flying, I am extremely vigilant with respect to potential onset of moderate or greater turbulence. I.e. I do not buzz along at Vne unless I am confident of conditions, and, when not confident, fly a rather conservative airspeed. Ridge crossings and valley exit/entries in particular. And, right now, in my rather low time condition, without commercial "pressures", I do not choose to fly when winds are in excess of 25KN, even though I am confident in both the ship and myself at wind velocities above that value.

Those mustering guys whip these machines around with great abandon at rather low airspeeds. That doesn't concern me, hooking a skid on a steer's horn notwithstanding ;). But at or near Vne one must be vigilant and conservative.

[[email protected]]

It's worth noting that the NTSB report is 20 years old and there should be a lot more data to analyse and perhaps draw some new conclusions from.

Is it just a poor combination of head design and rotor blade manufacture?

If it had been built with a simple teetering head instead of adding the flapping hinges, would that have prevented the extreme levels of flap required to strike the tail?

Hot and Hi Somebody please tell me. Richard's article is silent about this. you will just have to use your own judgement - that is what professional pilots do. If you are not sure of the amount of turbulence then don't enter it at Vne - go in slow and test the environment, giving yourself good safety margins and escape routes. You seem happy to be able to identify mild to moderate turbulence so if it starts to feel like the top end of your acceptable range, turn back or land but definitely slow down.

Birdy - didn't mean to patronise, sorry.

[Birdy2]

Yes JD, im sober now. ;)
And for a blade to hit the boom is one thing, but to slice any part of the cab is way past the teetering range, shearing tusks n all.

While low/0 G is an obvious no no with teetering rotors, a couple of the listed breakups were at or near hover.
No bad air and no indication of a collective dump.
Iv spent alot of time watching and in mustering R22s, in all types of air.
These machines are under real stress, way over Franks intended use.
Most attention in the report is on blade instability because of its integrity and inertia.
Hell, what iv seen robbi blades do with a skilled mustering pilot, with never an inflight chop up, i think the tree they are barking at is the wrong one.
Just dont add up.

Time for more reaserch for me.


Didnt feel patronised in any way Crab, my skin is pretty thick mate. ;)

[TTSN]

Yes JD, im sober now. ;)
And for a blade to hit the boom is one thing, but to slice any part of the cab is way past the teetering range, shearing tusks n all.

While low/0 G is an obvious no no with teetering rotors, a couple of the listed breakups were at or near hover.
No bad air and no indication of a collective dump.
Iv spent alot of time watching and in mustering R22s, in all types of air.
These machines are under real stress, way over Franks intended use.
Most attention in the report is on blade instability because of its integrity and inertia.
Hell, what iv seen robbi blades do with a skilled mustering pilot, with never an inflight chop up, i think the tree they are barking at is the wrong one.
Just dont add up.

Time for more reaserch for me.


Didnt feel patronised in any way Crab, my skin is pretty thick mate. ;)

I think the key difference here is airspeed, in a lot of instances the R22 is operated to extremes in the mustering environment but we never hear about low G mast bumping or in flight break ups with this type of use (unless someone can tell me different?). At the higher air speeds is where forces get to a point where catastrophic failures can happen extremely quickly if the rotor is unloaded for any reason (abrupt control movement, extreme turbulence). It is actually quite easy to exceed Vne in an R22 which makes me think what would happen if through momentary inattention someone was pulling excessive MAP and exceeding Vne when they hit a few small bumpy bits of air which would normally be within the aircraft capabilities? If for example R22's were always flown at 60kts (maybe even 70kts) then I don't think we'd have any of these mast bumping and in flight break up incidents.

[megan]

If it had been built with a simple teetering head instead of adding the flapping hingesHad not been aware of the flapping hinge, always thought it was just your regular Bell type teetering system, having had nothing to do with Robbies, but upon reading thought exactly the same as you Crab.

So the blade has two axis about which to flap. The head (teeter) and the flapping hinge. Seems a bit odd at first glance.

Would the inability of the blade to lead/lag in such a set up have any role to play?

[Birdy2]

TTSN,

On November 3, 1987, at approximately 1338 Pacific standard time, N8475A, a Robinson R22 Alpha operated by Helicopter Adventures, Inc., broke up in flight during a dual instructional flight near Moraga, California. The CFI and commercial helicopter pilot student, who was preparing to revalidate his CFI helicopter certificate, were killed. Witnesses reported observing the helicopter hovering at 400 feet agl when they heard the engine noise suddenly decrease, and a loud pop. The witnesses said they observed parts, "like sparklers," fall off the helicopter as it fell to the ground. The flight had originated 8 miles southwest, in Concord, California, about 1230, after having been refueled with 100LL fuel.

Hovering, ( no airspeed) 2 up and full fuel.
They are looking at rotor divergence at speed when light.
Not the case this time.
Every reported case states the machines were being opperated well within Franks limits, in mild conditions.

Quite a few witnesses state a tailwag or left right left right rolling before breakup, but none say a wild left roll ( low/0G) before breakup.

Sounds more like a main rotor phase issue, followed but a serious -AOA input to the MR.

Just an uneducated guess by an interested party.

[Birdy2]

Megan, the light metel robbi blades dont like to be flexed.
The added flap hinges are intended to relieve the bending stresses at the blade root when changes in G load produce changes in the coneing angle.

[Arm out the window]

Maintenance of the hinges would have an effect too, I would have thought - maintainers would know more than me, but the hinges in the Robbie head can vary quite a bit in resistance to movement depending on how old they are and how well they've been looked after, in my relatively limited experience.

They don't just see-saw freely like a Jet Ranger, and I bet the relative stiffness of the flapping hinge vs the coning hinges, and the overall stiffness of individual hinges, would make for quite some variation in the patterns of movement they develop when whirling around at silly speeds.

My thoughts are that if they're properly set up and maintained and the aircraft is flown sensibly, they will work as advertised, but if they were allowed to deteriorate it could be a different story. Again, I'm not massively high hours on type, but I've done quite a bit of throwing them around (smoothly and avoiding low g scenarios) without incident, and without feeling like I was coming close to any limits. Still, you wouldn't know if the blade missed the tail boom by a millimetre or a foot, would you?

I just try to treat them like any other teetering head machine - be smooth, don't bunt and don't flog it through turbulence.

[[email protected]]

Hovering, ( no airspeed) 2 up and full fuel. From my limited experience a Robbie doesn't have the power to hover OGE with 2-up and full fuel.

Sounds more likely to be engine failure, rapid Nr decay and then self-destruct mode to me.

[Paul Cantrell]

Crab: The teetering range is not the same as the flapping range as the hinges are separate and mostly independent of each other.


Crab, not sure if you quite realize how the Robby head works, apologies if I just misunderstood you.

Teetering and flapping are indeed the same thing on the Robby. The center hinge is the flapping hinge. The outer two hinges are coning hinges and perform the same function as blade bending in the Bell. It is possible to mis-rig a Robinson to flap around the coning hinges, but (I'm told) it flies really badly and you would know something was wrong with the rigging. Basically you set the friction of the hinges by the shim stack-up... part of the rigging (besides measuring the friction force with a special tool) is to check that when you lift the blades the blades move around the coning hinge: "Check coning hinge friction by lifting blades until spindle tusks clear droop stops. Hold one blade level and cone opposite blade. Rotor hub may not teeter as blade is coned. Repeat check on opposite blade".

There is 12° of flapping authority on the Robinson head.

The head design is indeed unique and patented by Robinson. Using coning hinges instead of a thicker/heavier blade kept the R22 weight low. Keep in mind that at the time, with only a 150 hp engine, Robinson was concerned with saving ounces, let alone pounds.

I've been teaching in Robby's for 30 years and have a great deal of respect for the people who produce them. I do think that the R44 is a better trainer than the R22, however there is a large part of the student population that doesn't seem willing to pay an extra $100/hr for the larger machine. Anyone who thinks it's a cute little trainer is crazy. It's a fun machine to fly, but it's nimble to a fault with not nearly enough inertia for low time pilots, IMHO, and it can bite hard if you don't know what you're doing. The R44 has much higher inertia and lots more available power in a training environment and I think makes a much better trainer than the R22 (but again, money). I learned flying R22s and it was a real financial stretch for me, so I totally understand people going for the absolute cheapest solution they can find.

I personally would welcome a different design head given the large number of inexperienced pilots who fly the Robinson. Of course, every head design has it's limitations, but eliminating the low gee issue probably makes sense.

[aa777888]

From my limited experience a Robbie doesn't have the power to hover OGE with 2-up and full fuel.

It will hover OGE just fine under those conditions.

https://c1.staticflickr.com/6/5515/30862215392_ccf67929ca_b.jpg

[evil7]

Hey Birdy2,

The report doesn't say "full fuel" - it only states that the flimsycopter had been refuelled with 100LL!!
No mentioning of quantity!

[megan]

The added flap hinges are intended to relieve the bending stresses at the blade root when changes in G load produce changes in the coneing angleThanks Birdy, but I must be missing something. If the blades are free to flap, why then the teetering head? I'm working on the basis that there's no such thing as a stupid question here, so be gentle.

[Spunk]

Wrong performance chart! It says R22 Alpha not Beta II. Maybe some more experienced R22 / IT nerd can upload the correct performance chart.

[[email protected]]

Paul Cantrell - thanks, every day's a school day on Rotorheads:ok:

aa777888 - that doesn't match what I saw of 2 of us with about 2/3 fuel struggling to get over the owners hedge without exceeding the MP limit. Or the lack of performance with the rather large examiner I did my check ride with - definitely not full fuel!

[aa777888]

Hi Crab--can't speak to the conditions that obtained for your flight, but I've been near max. weight and the Beta II's that I've been flying all make their numbers, no problem.

[[email protected]]

OK:ok: It was 20 plus years ago and I can't remember which model of 22 it was but it was UK at not much above sea level. I didn't see the owner do a load sheet so I have no idea how heavy we actually were.

[rotorfossil]

One of the problems of the difference between scheduled and real world performance of the R22 is the sensitivity of its small main and tail rotor blades to blade condition. Worst case scenario is warm humid day in summer and the leading edges plastered with bugs.The effects of humidity is not scheduled in the performance graphs as it used to be in old marginal performance helicopters (piston Whirlwinds for instance) and from memory could be up to 5 percent from dry to humid air. Cleaning the leading edges every sortie is a pain but can add the equivalent of about 5 bhp. Doesn't sound much but is the difference between a cushion creep and a more comfortable takeoff.

[krypton_john]

Spot on, rotorfossil, not to mention eroded and dinged up blade leading edges from flying through anything from rain to dust and debris blown up of dry landing sites.

[Birdy2]

Thanks Birdy, but I must be missing something. If the blades are free to flap, why then the teetering head?
The blades teeter on the central hub hinge, and can cone freely on the indervidual blade flap hinges.

You can split hairs if you like evil7.

[Rotor Kop]

That's really a grade3 mindset ...... if we take the millions of people killed every year in car accidents what now? Do we recall all cars?

[[email protected]]

If you have a specific car that has a serious defect causing deaths then yes, you would recall it.

You have to decide if the vehicle is fit for purpose or not.

Most people killed in cars are the victims of accidents of a variety of causes, very few of which are serious technical defects caused by design or manufacturing.

[Hughes500]

Crab

and to cap it all an automotive manufacturer will if in doubt recall his product. Does that happen in the aviation industry er NO

[TTSN]

If you have a specific car that has a serious defect causing deaths then yes, you would recall it.

You have to decide if the vehicle is fit for purpose or not.

Most people killed in cars are the victims of accidents of a variety of causes, very few of which are serious technical defects caused by design or manufacturing.
If the car manufacturer had a uniquely designed steering system that on quite a number of unexplained instances caused the vehicle to drive into the central reservation at motorway speeds then I'm quite sure it would be recalled until rectified.

Robinson has a unique design of rotor head (teeter and coning hinge layout) and it also has a unique problem that happens very occasionally and is as yet largely unexplained. A number of people feel the issue lies is in the balance between the teeter hinge and coning hinges (including some of the recognised world experts in the field). If someone unloads the rotor slightly (not as in an extreme low G situation) changing the coning angle and a coning hinge has any kind of change in standard resistance (sticks slightly / reacts slower for any reason) things can get out of hand very quickly. Unexplained rotor divergence is in the Robinson rotor head design - no other manufacturer has the unique design and no other manufacturer has the problem. Yes, we all know a Bell 206 can mast bump under extreme low G like any 2 bladed system but the Robinson is unique in that it has a history of largely unexplained rotor divergence incidents.

[henra]

If someone unloads the rotor slightly (not as in an extreme low G situation) changing the coning angle and a coning hinge has any kind of change in standard resistance (sticks slightly / reacts slower for any reason) things can get out of hand very quickly. Unexplained rotor divergence is in the Robinson rotor head design - no other manufacturer has the unique design and no other manufacturer has the problem.


:D
From quite a number of accidents and the witness descriptions it is blatantly clear that there must be something hidden in the Rotor systems dynamics that occasionally makes them go wild with little or no obvious trigger. A lot of witness reports describing a helicopter smoothly cruising along or at worst tail- wagging a bit (what they do seem to have in common that it almost always happened at >80kts) and all of a sudden a popping noise and bits'n pieces raining out of the sky. Far from the scenario Robinson is clinging to in their opinion of what happened in all those cases where the Robbies sliced their tail and spit their rotor.
Yes there is surely a number of traditional low G accidents or low RRPM accidents included but there is a number of accidents where both these scenarios quite obviously do not seem to be the case. (see witness descriptions and state of warning lights in some of the highlighted accidents).
And this is the really worrying part. Much beyond a helicopter which ultimately demands not to exceed stated flight limits.
Whether the underlying cause is rather in the triple hinge mechanism or in blade elasticity or lead/lag issues would potentially be a worthwile subject of study for NASA.

[[email protected]]

I had a look back to 2004 at a Robbie thread where the head design was discussed at length.

A contributor called Delta 3 had done a great deal of mathematical modelling and talked about how both the coning and the flapping (teetering) hinges had a delta-3 effect designed into them.

This 'double' delta-3 effect appeared to have the potential to give more than desired flapping in certain circumstances.

Don't suppose Delta-3 is still watching this forum?

[Birdy2]

A couple of points about the condition of the head hinges, if a flap hinge had more friction than the other, to the point where the many tones of centriphical tension couldnt break the binde, itd have to be sceezed compleatly. At worst, itd create a head shake that a pilot would notice an land asap. These hinges only need to move with G load ( coneing) changes, so itd only shake with a change in G load. If the central hinge sceezed and wouldnt allow the hub to rock, the teetering action would be transfered to the coneing (flap) hinges, again, only creating a stick shake.
If all 3 hinges bound, there would be a heavy left roll tendancy.
None of the above would cause the blades to suddenly and without warning, attack the machine.
In the list of incidents, the only pattern is that the blades suddenly, and without warning, violently depitch and mince the airframe.
Its been recorded to happen at any speed from hover to @90 kts, so AS can be rueled out.
Its happened with a wide range of AUWs, so disc loading can be rueled out.
Its happened, generaly at a steady cruise, but also dureing normal manouvers, but never recorded to happen with high rate, high magnitude control inputs ( mustering ops), so ham fisted pilots could almost be rueled out.
Low G roll is to the left. The incident reports list rotor strikes on every point of the compass, not consistant with low G strikes.

Probably millions of hours have accumulated in robbys, only 32 (?) have been recorded to self destruct with no indication as to why.
Sounds more like a rare structural failure, like maybe, phase lock.
Afterall, MR phase is only locked with two ball joints, loaded in shear, and not their intened design, tension.

Ready to stand as im corrected.

[TTSN]

Birdy2

I understand low G roll is always to the Right (not the left). A low G right roll can be at rates of 100 degrees per second, 25 years ago or so they used to be demonstrated by instructors along with the correct recovery actions. The tail rotor would need to be on the other side to make it roll to the left.

Related thread something happened in the hover which was posted in 2012 copied below:

anti-talk's 10th Dec 2012 15:30

This is very interesting, we had a 22 Roll over in the hover about 3 years ago that appeared to throw a blade - it was thrown well clear of the wreckage with no bending or discernable damage, the mast sheared at the gearbox and then the mast wrapped under the machine causing a pre impact fire due to ruptured fuel tank (as the mast cut through it)
Fortunately both occupants escaped the wreckage , the pilot stated he didnt grab a skid (dynamic roll over) and the machine literally inverted itself very violently (both occupants lost their shoes)
We were convinced this was a blade separation (query bolt failure??) we recovered the blade with hardly and damage, the Hub broke in two and the bolt was no where to be found.
As a result everytime the blades come off the machine we now replace with new bolts (never did like the 'stretching' idea.)
The local FSDO felt there was some mileage in the blade seperation idea but the NTSB had no appetite to investigate further due to there being no injuries. We retained the hub and I still have it to this day.

[TTSN]

And a case where a blade bolt failed (luckily when parked in a hangar) also from 2012 thread titled R22 Rotor Seperation Florida:

helichoppers's , 14th Jan 2013 13:55
Bolt Failure
Just to throw something else in to the pot..

We had an R44 Raven II that fortunately whilst sat in the hangar and not flying suffered a Blade Bolt Failure!

We returned to the machine after it had sat for a weekend to find a thrust washer sitting on the hangar floor! The full horror then dawned as you looked up to see one of the main Blade bolts sticking out from the Hub. If this had failed in flight and not whilst sat with the full weight of the blade on the droop stop I am sure the bolt would have totally departed from the aircraft along with the blade etc and you can imagine the rest....

The bolt was sent to our local CAA for inspection who then sent it to the FAA via Robinson, the opinion in the end was that it was a one off caused by Hydrogen enbritellment of the bolt and was not considered to warrant further investigation. The bolt had a total time of 80 hours from new.

I appreciate this was on an R44 not an R22 but the bolts must go through a similar manufacturing process??

I can email pictures if you PM with an email address me as I cannot seem to get them to insert to this post.

[rotorfossil]

This is just an opinion as I have no more evidence than anybody else about the unexplained breakups in cruise flight. However 20 plus years of teaching and examining in R22's suggests to me the following. If there is an unexpected power loss, the first reaction is "what's happening"? Followed by either far too slow lowering of the lever or no reaction at all. Result- massive drop in rpm, rotor blow back and break up. I have had two examples of this lack of reaction to real engine failures but not in R22's and in each case I had to slam the lever down. Sadly Robinsons edicts about simulations of engine failures result in most people have no experience of the rapid rundown in rpm in the event of power loss (and it doesn't have to be a total loss). Again my observation of people's behaviour suggests that the most likely cause of the power loss is due to lax operation of carb heating and undue reliance on the carb heat assist. Whatever the reason, if you get an unexplained power loss in an R22, after the inevitable " this can't be happening to me", you have to slam the lever on the bottom as fast as you can move your hand. Even then, the rpm will go down into the 80's. Unfortunately the autorotation entry as normally taught is much slower than this scenario and unexpected complete shutting of the throttle discouraged.

[Birdy2]

I hear what your saying TTSN, yes, some of these incidents could slip past the keeper as another low G boo boo, and some low G incidents could look like angry rotors.
Authorities seem fixated on head design/ blade stability.
After watching these machines for years being pushed way past Frankies limits and never a hint of blade instability tends to make me think they are very much under control.
Oh, and you caught my deliberate mistake with low G roll. ;)
Just checkn your on the ball. :)

[Arm out the window]

Again my observation of people's behaviour suggests that the most likely cause of the power loss is due to lax operation of carb heating

Yes, this always amazes me - a lot of people around where I am treat the carby heat as if it should always be locked off, even though the conditions (often very humid air and usually somewhere between 20-30 degrees C when airborne) are perfect for it.

Unfortunately the autorotation entry as normally taught is much slower than this scenario and unexpected complete shutting of the throttle discouraged.

I agree totally on the importance of making sure the lever goes down as quick as you can - the POH says not to do throttle chops because of the chance of the student doing the wrong thing or the engine stopping, but it's certainly a massive difference between a gentle coordinated throttle roll-off while the lever's going down and what would really happen if the power suddenly went away with the collective up, not to mention the oh **** factor.

[chopjock]

rotorfossil
Whatever the reason, if you get an unexplained power loss in an R22, after the inevitable " this can't be happening to me", you have to slam the lever on the bottom as fast as you can move your hand.

I'm not sure that's a good idea. Do that at 80kts and you risk a negative G event! Surely better to flare a little as you gently lower the lever eh?

[FlimsyFan]

rotorfossil


I'm not sure that's a good idea. Do that at 80kts and you risk a negative G event! Surely better to flare a little as you gently lower the lever eh?
Rapidly lowering the lever does not cause a dangerous low G event. From a pilot input perspective, low G is only of concern when induced by a cyclic pushover.

Am very much in agreement about the flare though. Some interesting work done by Dick Sanford (I think) that concludes (IIRC) - time available in cruise to fully lower lever to prevent catastrophic RRPM decay is approx 1s. Time available with no lowering of collective, but with progressive flare - circa 3s.

Haven't checked my facts on that, but he puts forward a strong argument that the flare is even more important during the 'Oh ****' moment than lowering collective. BTW, relates to R22.

[henra]

If there is an unexpected power loss, the first reaction is "what's happening"? Followed by either far too slow lowering of the lever or no reaction at all. Result- massive drop in rpm, rotor blow back and break up.



Among the tail chop incidents are surely some following this pattern. But from quite a number of descriptions it is very clear that there are other cases where droop of RRPM did not occur. Neither typical low G maneuvering with subsequent violent Right roll.
These 'unexplicable' ones are the real worrying ones since it is not clear how to avoid them. Due to rareity of events and the sudden progression once they occur I also slightly tend to assume something structural or combined aero- elastic + structural. Most of the totally inexplicable ones appear to have occured above 80kts. This also seems to point in the direction aerodynamic/aero-elastic.

[rotorfossil]

Chopjock. I agree that a flare is good news in power loss in the cruise. Unfortunately there are two scenarios when this is not a good idea, namely engine failure in the climb out and on the approach. Here you need to retain the speed that you've got. Bearing in mind that the problem is people not doing anything in timely fashion, a one size fits all reaction is the best that can be expected. My teaching was to lower the lever as smartly as possible and maintain or achieve a level attitude, which always requires a bit of rear cyclic.
Incidentally the same techniques are just as valid in the high inertia types like the 44, 66 and 206. Although the rpm don't drop as quickly, they don't recover very quickly either. Important in the failure on climbout case.

[blakmax]

Suggest you read http://www.ntsb.gov/safety/safety-recs/recletters/A08_25_29.pdf

[Hughes500]

You will find when you dump the lever in any helicopter the nose will immediately drop due to couple between weight and thrust, resulting in a natural tendency to apply aft cylic which then loads the disc.

[Thomas coupling]

when you dump the lever in any helicopter the nose will immediately drop

You sure about that Hughesy?:=

[Hughes500]

in 206,369,269,341,355,22,44 it seems to unless you are doing a quick stop or perfect zero wind hover if that is what you mean then stand corrected, but in forward flight they do

[Birdy2]

Dump collective, machine drops, airflow from underside, horisontal stabiliser raises boom, ( nose drops)

[[email protected]]

No, in forward flight it is essentially flapback/forward.

If you add or reduce collective, you change the pitch by the same amount all round the disc.

In forward flight there is a difference in V squared between the advancing and retreating side so the increase/decrease in pitch has a bigger effect on the advancing side. This is the same effect as introducing forward speed to a helicopter in the still air hover without changing collective pitch.

Therefore when you lower the lever the disc flaps forward (usually giving a nose drop) and when you raise the lever the disc flaps back. There may be some roll effects as well if the phase lag of the rotor system isn't exactly 90 degrees.

It has a correct term which I can't remember but it is something like Pitch Instability caused by Collective application.

The horizontal stabilisers and other airframe bits only cause any changes when the rate of climb or descent is established.

[Birdy2]

But when you dump collective, you have very little MR thrust, so itll have negligable effect on the airframe, till autorotation restores thrust.
Meanwhile, youv dropped and the HS has lifted to boom.

Or should i just stay under my rock?

[fadecdegraded]

Crab has nailed it in one

[JohnDixson]

Crab, Perhaps the collective to pitch attitude aerodynamic coupling is being underestimated, ( not to ignore the inherent rotor dynamics you mentioned ).

Best example I can recollect:

Original UH-60 prototype flew with a 60 sq ft. horizontal tail. The strategy during initial design was to meet US Army dynamic stability req'ts with only a pitch and yaw fluidic SAS. That later changed for the test machines, but the tail was designed around that idea.

Data point: in steady state autorotation at 120 KIAS with that tail ( fixed of course at that point ), the cyclic was almost on the aft stop, and the aft flapping was such as to result in contact with the aft damper stops. Has the feel of taking 51 cal hits. ( Just to be straight with this discussion: the inboard damper attachment point was the preceding hub arm back then, so the damper saw, and was exercised by, any steady atate flapping present. As a result, a damper attachment standoff was incorporated into the head, and that remains to this day ).

Couple of months later, the FBW stabilator was installed, and one of* the control laws integrated into the stabilator from the start was to uncouple the machine, collective-wise. This worked perfectly and resulted in no or minimal longitudinal trim shifts whether the collective was moved fast or slow, large trim shift or small.

* Once the decision was made to use a stabilator, all of the HQ and performance engineers jumped on those opportunities, as you can imagine, but that is another story.

[[email protected]]

Thanks John, it's good to clarify the difference between the initial rotor response to collective movement and the subsequent fuselage attitude and control positions once the climb/descent has been established.

[givdrvr]

I have occasionally pondered the potential role that unreported rotor head overspeed events could play in setting the stage for these these mishaps. Given that there are no readily identifiable witness marks from such rotor RPM only events and likely some considerable residual stress fatigue, multiple events could be absorbed unbeknownst to mx and later operators until the catastrophic unexplained departure from controlled flight occurs. There no databank of supporting evidence and its not statistically quantifiable so its just conjecture. Thoughts?

[megan]

givdrvr, in the days of the Bell 47 a rather common cause of engine failure was the dropping of valves. Cause given was unreported overspeeds inducing stresses which some time (hours & hours) later resulted in failure. Your theory is as good as anybodies at this stage I would say.

[blakmax]

only events and likely some considerable residual stress fatigue

See my previous posting.

[[email protected]]

An extract from Blakmax's posted link In addition, the bond joints between the spar and skin of the fractured main rotor blade
from the Fiji accident helicopter contained adhesive fracture features in many isolated areas of
the leading edge of the skin, indicating a weak bond. A weak bond in this area could allow the
leading edge of the skin to lift above the blade surface so that airflow during main rotor rotation
could peel the skin back further. If peel damage to the skin is minor, the main rotor blade will
vibrate irregularly, indicating that the helicopter must be landed immediately. However, if the
degraded bond on the main rotor blade is significant when the skin begins to peel, a large portion
of the skin may peel back suddenly, resulting in catastrophic fracture of the blade and complete
loss of control of the helicopter.

The Safety Board has determined that the adhesive fractures in the main rotor blade from
the Fiji accident helicopter propagated from the blade tip and leading edges and cannot rule out
the possibility that the in-flight breakup was initiated by a bond failure at the tip of the blade.
The indications of deteriorated bond strength uncovered in the main rotor blades highlight the
need for RHC and the Federal Aviation Administration (FAA) to address durability testing and
inspection of adhesive bonds in RHC helicopter blades.

So in addition to the suspect head design, you have suspect blade manufacture. when the crucial parts of your helicopter are held together by glue, you have to be bloody sure you have got the glue process 100% right.

[Birdy2]

Crab, you said,
In forward flight there is a difference in V squared between the advancing and retreating side so the increase/decrease in pitch has a bigger effect on the advancing side
Not being argumentative, just need to clear this in my head.
Would it also be correct to say that increaseing collective also increases the teetering angle for a given airspeed?
This changes the tip plane path, and so, the RTV, hence the need to pole forward with increased collective to maintain attitude.
Or do i still not get it?

[Arm out the window]

Sorry to jump in - I think Crab's saying that any change in collective pitch applies immediately and equally to all blades in terms of pitch angle.

Coefficient of lift is basically directly proportional to angle of attack anywhere below the onset of the stall, so with all other things being equal except speed (the advancing blade being quicker than the retreating one in forward flight of course), a given pitch angle increase will give you more of a lift increase on the advancing side than on the retreating side. Due to phase lag that will manifest itself as a pitch up (or conversely a pitch down if you're dumping the collective).

Once the rate of climb or descent builds up, then the effect of aerodynamic surfaces behind the center of gravity (e.g. stab / elevator, and tail boom itself) will act in the same way - pitch down for a descent, pitch up for a climb.

[RVDT]

will act in the same way - pitch down for a descent, pitch up for a climb.

Unless you are flying backwards?

Otherwise - what he said.

[[email protected]]

AOTW - yes, exactly what I was saying only better explained:ok:

Birdy2 - I suppose the teetering angle will change as the disc flaps up/down at the front but raising and lowering the lever should also change the coning angle.

[JohnDixson]

"Once the rate of climb or descent builds up, then the effect of aerodynamic surfaces behind the center of gravity (e.g. stab / elevator, and tail boom itself) will act in the same way - pitch down for a descent, pitch up for a climb."

The writing leaves the impression that it takes time ( I.e., getting to a new steady state condition ) for the aerodynamics to take effect. But in fact the aerodynamics take effect as soon as the collective moves, since the angle of attack on the tail, be it fixed or a FBW stabilator, changes immediately. Sorry for proposing an example that is hard for the posters to replicate, but if you take a machine like the S-70, get it to 150, and then do a series of collective inputs, up/down, various increments and rates , stabilator active and stabilator fixed ( electronics OFF ) you'd see the effect is immediate. Don't mean to over react and I accept what I think was the meaning of your statement, and am sort of fencing with the verbiage.

[[email protected]]

John, that's the problem with generalised statements regarding helicopters - there is always one which doesn't follow the norm and something with a variable stabilator will inevitably behave differently to something with a simple fixed stab.

It's worth highlighting that designers make all sorts of adjustments to their control rigging to overcome these basic aerodynamic effects using mechanical (mixing unit) or electrical (AP computer) inputs.

Sikorsky made the starboard lateral control run slightly longer (using the mixing unit) to help compensate for tail rotor drift and roll on the Wessex and Sea King and the Lynx has a very strong collective to fore and aft pitch interlink to counter the 'flapback' effect of raising and lowering the collective.

[JohnDixson]

Had a chance to fly the prototype Lynx with Roy Moxam in 1974, who briefed and demonstrated the collective G compensation sub-system. Worked fine. For a short while, we were planning on teaming with Westland, back when the USN idea on LAMPS was a small machine.

[[email protected]]

As we have discussed before John, the Collective Acceleration Control (CAC) activated at around 2G (we used to demonstrate it in a 60 deg AoB turn) and it took off collective pitch equivalent to about 15% Tq. You added more collective to maintain the turn but had to be careful to lower the lever again as you rolled out and reduced the G loading or you could overtorque.

I was told by the old and bold that it was designed in to the aircraft to try and reduce the severity of a pitch lane runaway.

[JohnDixson]

That was awhile ago, Crab, but my dim recollection was that it was intended to soften the ride in turbulent air. Sort of a rigid rotor electronic version of an articulated rotor head delta three hinge. Same idea anyway.

[megan]

Seem to recall flying the Huey on fixed floats when empty (aft CoG) the Vne was limited to 80 knots so as to be able to control the pitch up if Mr. Lycoming decided to take the day off. At 100 knots, the normal Vne, the cyclic was buried in the instrument panel in such conditions. Memory is decades old, so details may be a little off.

[[email protected]]

That might have been an additional benefit John but you would have to be in some serious turbulence to experience 2 G. I have had the CAC activate when mountain flying in very strong winds but that was in fairly extreme conditions.

One problem with the CAC was that it could runaway itself and they had to add a CAC cutout to the cyclic. The problem was to do with a 'wiper' style electrical contact for collective position that could be dislodged; I had this happen with a student conducting an AFCS out landing - all hell broke loose as we touched down (firmly but not hard) with severe vertical oscillations until the CAC cutout was pressed.

The G-meter on the aircraft registered +3.5G and -1.5G so I shut it down and it went home on a truck.

[Arm out the window]

Memory is decades old, so details may be a little off.

No, that's spot on, Megan, I remember it well - a huge forward cyclic input required on entering auto, and also the strong tendency to roll opposite the direction of yaw if out of balance because of the heaps more surface area below the c of g.

The writing leaves the impression that it takes time ( I.e., getting to a new steady state condition ) for the aerodynamics to take effect.
Fair enough that there would be an immediate change in angle of attack on the stab due to the change in downwash, but there'd also be a little bit of lag while the rate of descent built up, wouldn't there? That's all I meant.

[claudia]

Great engineering knowledge by all but NO pointers as to why these Robbos are
disentegrating in straight and level flight even when flown by very experienced pilots.
Hence their inclusion in the "watch" list.-- never again sit in one .

[claudia]

Robinson now has the problem solved. Read their safety letter of 18th November.!!
Just slow down, do not speak to your passengers, dont change any radio frequencies
and everything will be ok.
Laughable if it wasnt such a serious issue.

[[email protected]]

Don't fly fast - don't overcontrol in turbulence - maybe just don't fly their helicopters:E

[Hughes500]

To be fair one should slow down a bit in strong turbulence ! As to not speaking to the pax, depends who you have on board I suppose

[[email protected]]

If it is an issue of division of attention when talking to pax that might distract the pilot from accurately and smoothly flying the aircraft - then surely the same must go for speaking on the radio, just as much of a drain on the brain. So, another don't for the list when flying a Robbie:E

[claudia]

H500. Yes, in the 500 you can talk to your passengers if you so wish
but in a Robbo talking to them is simply too dangerous. It could result
in the machine falling apart.!

[HeliHenri]

.
Robinson Helicopter Co's passenger warning is 'bizarre', says expert - NZ Herald (http://www.nzherald.co.nz/transport/news/article.cfm?c_id=97&objectid=12025194)
.

[Vertical Freedom]

Thanks HeliHenri; Incredible...Engineered to Self-Destruct in Flight :eek:

[[email protected]]

"Robinson seem to assert this 'risk' is because a passenger is on board and not in any way associated with a design fault of the helicopter."

Robinson helicopters make up 35 per cent of the New Zealand fleet but 49 per cent of accidents, 64 per cent of fatal crashes and all seven fatal mast-bump accidents.

The company has blamed many accidents on poor pilot training, while critics have contended the helicopter has a design flaw.
that seems to be the two sides in the ongoing debate about Robbies in a nutshell

[Thomas coupling]

Vindicated - all those who believe Robbo's are death traps, even in the right hands.

The DoC in NZ have now permanently suspended the use of Robbo's going fwd. What more of an indictment could you have?

Now the Robbo company are "insinuating" that even distracting a pilot during their normal duties, might be enough to push the robbo closer or even into it's notorious mast bumping limits.

When will people wake up to the fact that cheap isn't always cheerful!

[SASless]

So, another don't for the list when flying a Robbie

Crab Dear Boy, Prevention is the best Cure!

Every time I even see a Robbie....I head to my fav Burger Bar and order up a Double Whopper with Cheese with a Large order of Fries and wash it down with a Chocolate Milkshake to ensure I cannot fit inside one of the things.

[gulliBell]

Whenever I hear a 212 fly over I look up in appreciation...whenever I hear an R-something fly over I just keep doing what I was doing.

[r22butters]

If Kiwi's can't handle little old Robbie then stop fly them!

If slowing down in turbulence is to much of a burden, then stop flying a machine that requires it!

If you don't like the design of the rotor head, then stop your bitching and go fly go something whose rotor head design makes you feel nice and comfy!
:rolleyes:

[Bell_ringer]

Whatever the actual cause of the Robbie woes are in Kiwi-land, at some point the high accident and fatality rate negate the cost benefits of operating one in a given environment
Continued use by the government departments could also have liability implications if they didn't choose to make the changes they have.

A 9x higher rate of mast bump accidents vs the US is significant, it would seem common sense to invest in machinery that have a more mundane accident history in similar conditions.

[heliduck]

Whenever I hear a 212 fly over I look up in appreciation...whenever I hear an R-something fly over I just keep doing what I was doing.

It’s not just me then!!

[Thomas coupling]

Whenever I hear a Robbo, I make sure it isn't flying directly over me!

[noooby]

It is nothing to do with Robbies in NZ. It is a Safety Notice published by Robinson, in June 2017, that the media have just picked up on.

When you read it, it actually isn't anything that pilots aren't already aware of. Passengers can be a distraction. Link here:

https://robinsonheli.com/wp-content/uploads/2017/06/rhc_sn44.pdf

Not that I'm a big fan of Robbies, but I think the media are making a mountain out of a mole hill with this one.

[r22butters]

I just love flying a helicopter that so many internet experts are so affraid of that they feel the need to mock it at every opportunity.

This apprehension of the helmet heads is a never-ending source of amusement for this simple little Robby guy!
:8

[Thomas coupling]

Look at it this way R22butters - someone has to fly them. Remember the Trabant?

[KiwiNedNZ]

"I just love flying a helicopter that so many internet experts are so affraid of that they feel the need to mock it at every opportunity. This apprehension of the helmet heads is a never-ending source of amusement for this simple little Robby guy!"

Funny how you call some of the industry's most experienced people here in Rotorheads internet experts. That Robbie Rider is as far from fact as you can get. This isn't facebook and actually knowing who the majority are behind their user names here you are way off base.

[r22butters]

"I just love flying a helicopter that so many internet experts are so affraid of that they feel the need to mock it at every opportunity. This apprehension of the helmet heads is a never-ending source of amusement for this simple little Robby guy!"

Funny how you call some of the industry's most experienced people here in Rotorheads internet experts. That Robbie Rider is as far from fact as you can get. This isn't facebook and actually knowing who the majority are behind their user names here you are way off base.

Shouldn't you be outside gazing lovingly up at the sky, your heart swelled and a tear in your eye,...a 212 is flying by!:D

[KiwiNedNZ]

Maybe you need a good pair of glasses moron - I never said anything in my post about 212s. You come on here and insult a lot of the industrys most respected pilots and then turn around and take a shot at me for a post I didn't even make, stick to flying your Robbie - ******.

[SuperF]

He doesn't fly Ned. He is someone that has trained and now cant get a job anywhere, and when you see his negative whinging posts on this and other forums(under the same name) you can see why he never has and never will get a job...

The epitome of a "skidbitter"

[Rotor Kop]

It is nothing to do with Robbies in NZ. It is a Safety Notice published by Robinson, in June 2017, that the media have just picked up on.

When you read it, it actually isn't anything that pilots aren't already aware of. Passengers can be a distraction. Link here:

https://robinsonheli.com/wp-content/uploads/2017/06/rhc_sn44.pdf

Not that I'm a big fan of Robbies, but I think the media are making a mountain out of a mole hill with this one.

Exactly - a bunch of school children here. Why comment if they have nothing positive to say??? Seriously grow up and get a life.

[aa777888]

Sadly, a lot (not all) of these safety notices remind of plastic bag suffocation warning labels. Not useful for normal folks, vitally important for the insurance and legal industry.

[The Nr Fairy]

If a Robbie is flown inside the limits, then they're as safe as the next helicopter. Mast bumping isn't unique to the Robinson series. I remember seeing a film made by the US Army about Hueys getting mast bumping.

What FR did was to reduce the cost of entry into helicopter ownership which let more people learn to fly. And when the most important attribute when flying *anything* is a professional, cautious attitude then those who don't bring that to the party put themselves at higher risk.

I'd hazard a guess that any higher accident rate for Robbie is also contributed to by their sheer number - you see a lots of crashes involving Fords and Toyotas, less involving Ferraris and Lamborghinis, but they still happen.

[[email protected]]

Watch the video on Heli henri's NZ Herald link to understand why mast bumping is much more dangerous in a Robbie than other 2-bladed helos!

The problem comes when you use a Robbie in turbulence (just the sort of thing you get in mountain flying) - it isn't built for it which is why the NZ DoC have stopped using it.

Yes, it is a cheap way to get into helicopter flying but it was built as a commuter machine not a training or commercial one.

You can pretend all you like that it is as safe as any other helicopter but only in certain (smooth) conditions and when flown considerately.

[Bell_ringer]

The Robbie faithful always quote the huey video of 40 years ago.
The difference is that the occurrences came to a halt with training.
In a Robbie, despite training and the benefits of all the previous lessons learned, the phenomenon continues to happen every year.
This shouldn't come as a surprise. If Robbie think their pilots need to be reminded about passengers then it's unlikely any other training will stick. :E

[noooby]

crab, give Simon Spencer-Bower a call in Wanaka. He has over 15,000 hours in Robbies. Over 21000 hours total. In the mountains in NZ. Most of that 15000 is in the R22.

If he isn't the highest time Robbie pilot in the world, he is pretty damn close.

He'll teach you a thing or two about Robbies and give you an honest rundown of their strengths and weaknesses.

[r22butters]

Watch the video on Heli henri's NZ Herald link to understand why mast bumping is much more dangerous in a Robbie than other 2-bladed helos!

The problem comes when you use a Robbie in turbulence (just the sort of thing you get in mountain flying) - it isn't built for it which is why the NZ DoC have stopped using it.

Yes, it is a cheap way to get into helicopter flying but it was built as a commuter machine not a training or commercial one.

You can pretend all you like that it is as safe as any other helicopter but only in certain (smooth) conditions and when flown considerately.

I've had turbulance kick the **** out of me while flying both the 22 and 44 plenty of times and I never came close to mast bumping, or even low-g!

,...but then again I slowed down.
:ugh:

[[email protected]]

Nooby - I would hope that someone with that amount of experience could handle a Robby well but more importantly know where to avoid turbulence in the mountains and how to deal with it if encountered.

If it isn't an issue, why have DoC NZ taken action following a series of incidents???

R22 - goody for you, I suspect what you call getting the sh*t kicked out of you in turbulence probably isn't very high on the scale.

[r22butters]

Nooby - I would hope that someone with that amount of experience could handle a Robby well but more importantly know where to avoid turbulence in the mountains and how to deal with it if encountered.

If it isn't an issue, why have DoC NZ taken action following a series of incidents???

R22 - goody for you, I suspect what you call getting the sh*t kicked out of you in turbulence probably isn't very high on the scale.

Yeah, you're probably right. When I become more experienced, I'll start blaming the helicopter like all you other super pilots!
:D

[Hot and Hi]

Yeah, and mine is bigger than yours.

Are there any objective metrics for turbulence, which are commonly used? (Leaving aside for a moment the question how to practically measure and/or record them in light singles ...)

[Bell_ringer]

Yeah, and mine is bigger than yours.

Are there any objective metrics for turbulence, which are commonly used? (Leaving aside for a moment the question how to practically measure and/or record them in light singles ...)

Objective metrics is always a challenge as it requires a common unit of measurement.
How many other aircraft have inflight breakups, particularly with the tail found far behind the rest of wreckage?
Robbies on average, despite their popularity, account for only a third of hours flown.

[r22butters]

The fact is that Robby's have limits. You can either accept those limits and have a happy career, or you can ignore them and die!

There was a guy who used to fly his Robby into the clouds a lot, and then post videos on youtube of his awesomeness. Then he died flying his Robby into the clouds!

I don't know why Kiwi's have such a problem with mast bumping their Robbys, maybe their turbulence is different than everyone else's

Whatever it is, Kiwis and Robbys just don't mix, and they should probably just stop flying them!

[Bell_ringer]

Every aircraft has limits. They are usually quite well documented and not determined by how well or badly you play rugby.
The DOC hasn't limited their choice of aircraft to any other type. Robinson seem to believe their aircraft are fine but it's clearly kiwi pilots, yet they seem to manage with the other aircraft manufacturers.

[[email protected]]

Objective metrics is always a challenge as it requires a common unit of measurement.Turbulence that significantly reduces the G below 1 or leaves you feeling light in your seat would be a good place to start.

Not a good place to be with a Robinson rotor head.

The fact is that Robby's have limits. You can either accept those limits and have a happy career, or you can ignore them and die But only the Robbie has had them added to (reduced speed envelope) following a series of accidents and a great deal of pressure from concerned aviators.

As you come to acknowledge your own limitations - as I suspect many of us older types here have - it is reasonable to question those of the machine as well rather than assuming that everyone who hasn't crashed in a Robbie is awesome and those that have, brought it on themselves.

[malabo]

R22butters, leave it alone on this forum, you’ll only catch grief. I paid my way from the civilian side and learned, instructed, and flew lucrative contracts on the 22. Retired flying Super Pumas and AW139. Would never have happened without a cheap entry, and side-by-side with other professionals found zero difference compared to the crabs of the world that silver-spooned up through the military.

Now my kiwi friends tell me that the reason for the disasterous record in NZ is from a disfunctional regulatory regime. Outside NZ I’ve found their pilots as good as any and better than most. Perhaps KiwiNed can comment on the quality of regulatory oversight in NZ, and its effect on the accident rate.

[[email protected]]

crabs of the world that silver-spooned up through the military that is a pretty pathetic remark. You paid for your position - I earned mine.

[r22butters]

Turbulence that significantly reduces the G below 1 or leaves you feeling light in your seat would be a good place to start.

Not a good place to be with a Robinson rotor head.

But only the Robbie has had them added to (reduced speed envelope) following a series of accidents and a great deal of pressure from concerned aviators.

As you come to acknowledge your own limitations - as I suspect many of us older types here have - it is reasonable to question those of the machine as well rather than assuming that everyone who hasn't crashed in a Robbie is awesome and those that have, brought it on themselves.

You don't have to be an awesome pilot to not crash a Robby, just one who can read the manual and follow instructions!:ugh:

[WillyPete]

There was a guy who used to fly his Robby into the clouds a lot, and then post videos on youtube of his awesomeness. Then he died flying his Robby into the clouds!


Is that the guy shown covering his dials in the videos of his flights?

[SASless]

that is a pretty pathetic remark. You paid for your position - I earned mine.

Sometimes that military silver spoon comes at a mighty stiff tariff!

Crab can be outspoken at times....Lord knows he and I have crossed Swords often but in this case I choose to stand with my ally and brother-in-arms!

There is a huge difference between buying a pair of wings and earning them after they are pinned on your tunic!

[SuperF]

The big problem is picking the turbulence. Sometimes it will kick the s*#t out of you earlier than you thought you were going to get it, and sometimes you get none when you are sure you should get some....

Some of the Robbys that have gone down in NZ have been in the lee of the hills with 30-40 kts coming through them, i wouldn't try that in a JR or Huey, so those ones probably did mast bump, but you can't blame the machine. You hear about the aircraft gone missing, look at the weather and ask WTF were they doing in that aircraft, in that location!!

The ones that are a worry, are when they have mast bumped in what should be very calm air. There are at least three in NZ that the weather was virtually calm and they are saying it was turbulence... One particular other helicopters were in the area prior to the accident no wind, and then aircraft out searching within 20 min, no wind. Where do you get turbulence in those cases??

[SuperF]

Oh and Crab, i may give you grief sometimes, but i stand with sasless. anyone that serves their country gets my respect.

[DOUBLE BOGEY]

I am with Crab too. Passing military selection and the spending nearly 200 hours training under intense scrutiny, always only 5 hours away from review and the chop, is a mission.

Long term survival in this business requires some manipulation involving the types you fly, the organisations you fly for and the scope of the missions you do. After tha, Lady Luck and fate are waiting in the wings.

Having said that let's not trash Butters. His message is really valid, know the limits and apply them. That is all he is saying. As to the Robbie, don't know enough about the. flew an R44 once and was mildly alarmed that the governor is not in parallel to the throttle control and felt weird as I moved the collective and the throttle turned in my hand.

Good luck to all the Robbie jockeys. Follow Butters advice. It's surely a good place to start.

[Jeffory]

If only everyone could train on and then jump into a turbine machine from day one.

The fact is that this is not the case, just like how not everyone can go the mil path for various reasons.

To those whom believe pilots haven't earnt their wings because they "paid" for it, that is a disgraceful view. We're all in it for the same reason, hard work is required on both sides of the fence.

[[email protected]]

To those whom believe pilots haven't earnt their wings because they "paid" for it, that is a disgraceful view. We're all in it for the same reason, hard work is required on both sides of the fence.Jeffory - you are quite correct and the last thing we need is another civ vs mil willy-waving thread - I just responded to malabo's rather unnecessary jibe.

I quite agree that whichever route you take involves hard work - the insinuation that mil training is somehow a gift is an insult to all those who serve their country rather than just themselves.

PS - the support is gratefully accepted on behalf of all mil aviators.

[cattletruck]

My very first 3 hours in an R22 (under supervision) were in very challenging conditions of wind 25 knots gusting to 30-35 knots. My 4th hour on type was in light and variable conditions and I remember thinking what a false sense of security it was because it was incredibly easy to fly.

Later I would solo in similar challenging conditions and after pulling take-off power it felt like the thing was gonna fall apart in flight so I reduced the collective as there was enough wind providing translational lift anyway, albeit it was quite a bumpy take-off. A few years later I would see someone taxying one at Bankstown Airport under similar windy circumstances and doing it very well - it can be done. I believe these operating conditions are now banned for an R22, probably because the fair weather flyers get themselves caught out.

It isn't the mast that's the Robbi's weakness, it's the lack of weight (and possibly the narrow power band from the engine) that makes it unstable when circumstances become demanding.

As for the mil vs civvy argument, it takes courage to sign up your life to the military as there is no buying your way out of a situation you don't like. The mil pilots I know all flew planks before they were given their limited choice of career progression. Although I did think it novel that some AS350 pilots thought the rubber band set up on our "trainers" was silly until I explained to them that it also absorbs the vibrations from a reciprocating engine.

[r22butters]

My very first 3 hours in an R22 (under supervision) were in very challenging conditions of wind 25 knots gusting to 30-35 knots. My 4th hour on type was in light and variable conditions and I remember thinking what a false sense of security it was because it was incredibly easy to fly.

Later I would solo in similar challenging conditions and after pulling take-off power it felt like the thing was gonna fall apart in flight so I reduced the collective as there was enough wind providing translational lift anyway, albeit it was quite a bumpy take-off. A few years later I would see someone taxying one at Bankstown Airport under similar windy circumstances and doing it very well - it can be done. I believe these operating conditions are now banned for an R22, probably because the fair weather flyers get themselves caught out.
.

Yes, before I got my private in 2003 they placed restrictions on wind and turbulance until you have 200 hours total with 50 hours in the R22.
http://https://robinsonheli.com/wp-content/uploads/2016/03/r22_poh_2.pdf

The 22 is a lot of fun to fly, but please remember, its a Yugo, so don't drive it like a Ferrari.

[Hot and Hi]

The fact is that Robby's have limits. You can either accept those limits and have a happy career, or you can ignore them and die

But only the Robbie has had them added to (reduced speed envelope) following a series of accidents and a great deal of pressure from concerned aviators.
Is that really so? And what about the envelope restrictions that at some point were added to the AS350 Squirrel POH, meant to help pilots to avoid, detect, or get themselves out of hydraulics failure induced by a combination of high speed, high collective and cyclic pull? It is being discussed as we speak in a parallel thread right here in the Rotorheads Forum: https://www.pprune.org/rotorheads/229370-as350-astar-squirrel-41.html#post10110061

Immediate action if required to reduce the feedback loads [stemming from temporary hydraulics failure]: Reduce the severity of the maneuver ...
In maximum power configuration, decrease collective pitch ... before initiating a turn...
In hover, avoid rotation faster than 6 sec per full rotation.

I guess these are in itself serious limitations. At the same time, it seems quite possible for most normal missions to stay within the limited envelope and to never encounter the hydraulics problem. Clearly, Robinson is then not the only helicopter with design-related envelope limitations.

It is interesting to see that while here you say only Robinson had to limit the flight envelope, you are the main contributor to the AS350 limitations related discussion in the "AS350" thread. Both in one day.

I guess what we see here is actually quite normal. I could think of different, specific limitations applying to respective other types of helicopter.

[[email protected]]

Not really limitations - no limits on speed, angle of bank or AUM.

Which other manufacturer has to run a safety course for its helicopter?

[FlimsyFan]

Not really limitations - no limits on speed, angle of bank or AUM.

Which other manufacturer has to run a safety course for its helicopter?

As usual, watching the Robbo bashing from the sidelines...

I think that’s a fair question, but I reckon it says more about the pilots than the helicopters.

There’s a very high percentage of amateur pilots in Robbis, often people not used to being told ‘No’, often people expecting a positive outcome in spite of the circumstances, and sometimes people flying an aircraft with other things on their mind.

I don’t have the facts to hand, but imagine the bigger, more expensive stuff has a pro behind the stick more often than not.

I have done the Robinson course and found it very enlightening. Much of the message is about Airmanship and is transferable across any platform. Remember that by far the biggest killer in Robbis, despite the mast bumping issue, is flight in DVE. Decision making by amateur pilots is frequently very, very poor. The nature of the course has most certainly underlined for me the risks that human factors will expose you to.

That said, I fear that the basic messages from the course are most needed by those who feel they don’t need to do the course in the first place. And yes, that includes the one about how distracting passengers can be

[heliduck]

Robbie’s have mast bumping, AS350’s have servo transparency, jetrangers have LTE, etc., etc., etc..... Most machines have a weakness somewhere that we need to be vigilant with when operated at or beyond they’re designed envelope. I’ve spent a lot of time mustering in R22’s & shooting in R44’s, great machines even when pushed a bit harder than Frank intended.
Robinson tend to address pilot error with safety notices etc. whereas other manufacturers ignore it as it’s not their fault, credit to Robinson in a litigious world that they do that.

[Ascend Charlie]

Robbie’s have mast bumping, AS350’s have servo transparency, jetrangers have LTE,

OMG, another believer in the LTE Myth. But that is another matter completely.

Every teetering head is subject to mast bumping, but the R22 seems to have more of it due in part to factors mentioned above.

The 407 has limitations imposed on speed due to the force on the tailboom imposed by large pedal inputs (plus they had to create a pin to drop into the system to limit the physical displacement above certain speeds. (Sorry to be vague but it is 20 years since I flew a 407)

[r22butters]

OMG, another believer in the LTE Myth. But that is another matter completely.

Every teetering head is subject to mast bumping, but the R22 seems to have more of it due in part to factors mentioned above.

The 407 has limitations imposed on speed due to the force on the tailboom imposed by large pedal inputs (plus they had to create a pin to drop into the system to limit the physical displacement above certain speeds. (Sorry to be vague but it is 20 years since I flew a 407)

Well, at least Robby's don't believe in LTE.:eek:

[heliduck]

OMG, another believer in the LTE Myth.
Quite the contrary, I believe LTE stands for “ lack of training & experience”.
You missed my point entirely, none of the above mentioned issues are a phenomenon which sneaks up on you when least expected, they are all very well known & predictable aerodynamic functions.:ok:

[Bell_ringer]

When an older Bell has come short because of issues with the feet, tail or somewhere in between the evidence has clearly determined what the cause was.
The same applies to the flying bus and it's hydraulics or indeed any other non-RHC aircraft.

The crux of the issue is that for a very long period of time (and it continues today) a Robbie comes to grief midair, showering the countryside with pieces and the events leading to the accident are generally not easily identified or identified at all.
The goto point then becomes wind or turbulence and by default, therefor, the pilot. This makes the Robbie faithful comfortable as it would never happen to them, they are much more experienced and capable than those that wilfully ignore all the warnings.

If you look at enough cases what you find is that these accidents also occur with experienced pilots and in weather that couldn't be shown to be rough.

All the other manufacturers account for for approximately two thirds of the hours flow, many operated in far less mundane environments (mustering certainly isn't mundane but those accidents tend to involve becoming one with a tree or wire) and with higher seating capacity yet they account for the smaller percentage of fatal accidents.

The Robbie's apparent flaws are nothing new, so the risks shouldn't be anything new to those that fly them.
The Robbie was made to be cheap, it is what made it affordable to train on and accessible to many smaller operations who could simply not afford anything better.
Given the choice today I would rather be trained on a Cabri, which has recently been stealing Robinson's lunch money. Hopefully they get a 4-seater going, that could really create a few ripples in the piston waters.

[[email protected]]

Bell ringer :ok::ok::ok:

[Rotor Kop]

Is that really so? And what about the envelope restrictions that at some point were added to the AS350 Squirrel POH, meant to help pilots to avoid, detect, or get themselves out of hydraulics failure induced by a combination of high speed, high collective and cyclic pull? It is being discussed as we speak in a parallel thread right here in the Rotorheads Forum: https://www.pprune.org/rotorheads/229370-as350-astar-squirrel-41.html#post10110061



I guess these are in itself serious limitations. At the same time, it seems quite possible for most normal missions to stay within the limited envelope and to never encounter the hydraulics problem. Clearly, Robinson is then not the only helicopter with design-related envelope limitations.

It is interesting to see that while here you say only Robinson had to limit the flight envelope, you are the main contributor to the AS350 limitations related discussion in the "AS350" thread. Both in one day.

I guess what we see here is actually quite normal. I could think of different, specific limitations applying to respective other types of helicopter.

Agree with you - And what about the Bell 407 that also had a number of fatalities and the speed was reduced?? Biased anti - robbie guys should rather open their own thread under the nursery school section....

[Bell_ringer]

..And what about the Bell 407 that also had a number of fatalities and the speed was reduced?? Biased anti - robbie guys should rather open their own thread under the nursery school section....

It may help to be factually correct.
The early models experienced incidences of tail rotor strikes eventually believed to be a result of a combination of excessive pedal usage, speed etc.
The solution was a pedal stop relay which are fitted to all of the 407's.
VNE reduction was temporary and it operates today at the 140kts VNE that it was released with.
Bell didn't just blame their pilots, they engineered a solution to the problem.

It is also worth remembering that these issues were found on what was, then, a young aircraft (late 90's) compared to ongoing issues with a family of aircraft that were introduced in the late 70's, or early 90's for the 44.

[Thomas coupling]

I guess what the 'fraternity' is saying is that ALL 'normal' helicopters which had their achilles heels - have been either engineered out or safeguarded in such a way that a particular model continues to be produced and the symptoms rarely if ever manifest themselves again.

BUT the Robbo has been with us now for 38 years :rolleyes: and STILL it has that allegedly inherent ability to KILL mostly unsuspecting pilots but also some very highly qualified pilots due predominently because of its mast bumping inadequacies.
And the reason why 'Frank' can/t/won't engineer the problem out is because it would no longer be a Robbo! It would cost a lot more and behave differently - which would take away the reason for its existence.
Build 'em cheap, sell 'em cheap and hope the attrition rate is accepted by industry (which it obviously is, in most operating areas).

I can't think of another manufacturer who has his own Safety Course - to bring the inadequacies of the aircraft customers are flying around in - to their attention.

I buy a cheap and cheerful car - I don't want to go back to school to understand that what I bought is 'maybe' a handful in certain circumstances and the wheels might come off .....especially when my family are involved.:hmm: