Fatal Crash Broome 4th July 2020

[Twist & Shout]

From the ABC:


Two people have died and two are in critical condition after a helicopter crashed in northern Western Australia.

The aircraft, which has been identified a Robinson R44 helicopter, crashed on Antheous Way, Bilingurr, a northern suburb of Broome, just after 2:30pm.

WA Police said an adult occupant of the aircraft died at the scene from injuries he sustained in the crash.

A young girl who was a passenger in the aircraft was taken to Broome Hospital, but has since died from her injuries.

An adult and child who were passengers in the helicopter remain in critical condition.

Police and emergency services are at the scene and have set up a cordon on either side of the crash site.

The sirens of a large-scale emergency response could be heard across Broome.

"It's a pretty horrific sight," one person said.

"You can hear the sirens from everywhere in Broome.

"I'm not sure if anyone witnessed it, but it looks devastating."

The Australian Transport Safety Bureau said it would be sending officers to Broome to investigate the crash.

[capngrog]

There are a couple of helicopter sight-seeing tour operators flying out of Broome International Airport, located approximately 1-1/2 miles south of the crash site ... possibly one of theirs? It is especially tragic when recreational activities result in fatalities. R.I.P.

Regards,
Grog

[Twist & Shout]

There are a couple of helicopter sight-seeing tour operators flying out of Broome International Airport, located approximately 1-1/2 miles south of the crash site ... possibly one of theirs? It is especially tragic when recreational activities result in fatalities. R.I.P.

Regards,
Grog

Very possibly. The sex/age of the victims indicate it could also be a family. Adult male deceased at the scene. 11yo girl succumbed in Broome hospital. Adult female and another child airlifted to Perth. (All according to the news reports.)

[megan]

Horizontal Falls Seaplanes, Robinson R44 according to Pacific forum

[Cloudee]

Founder of Horizontal Seaplanes named as one of those on board the R44.

https://www.abc.net.au/news/2020-07-05/troy-thomas-killed-in-broome-helicopter-crash/12423668

[RickNRoll]

Tail rotor came off not long after takeoff. Had experienced unusual vibrations in the days before.

https://www.abc.net.au/news/2020-07-10/atsb-says-tail-rotor-separated-before-broome-helicopter-crash/12443298

A helicopter that crashed in the suburbs of Broome last weekend, killing two people, had experienced "unusual" in-flight vibrations two days before the incident, investigators say.
Key points:

Investigators say the helicopter's tail rotor broke apart shortly after take-off
People who flew the aircraft in the days before the crash had reported "unusual" vibrations
The ATSB advises R44 pilots who experience unusual vibrations to land as soon as possible

The Robinson R44 crashed on Saturday afternoon shortly after take-off, killing 40-year-old pilot Troy Thomas and a 12-year-old Perth girl.

Mr Thomas's 12-year-old daughter, Mia, and Perth woman Maddison Down, 24, remain in a serious condition in Perth hospitals.

In its latest update, the Australian Transport Safety Bureau (ATSB) said the aircraft's tail assembly had broken apart shortly after take-off.

"The tail rotor gearbox assembly, tail rotor and empennage assembly separated soon after the helicopter lifted off," it said.

https://www.abc.net.au/news/2020-07-10/atsb-says-tail-rotor-separated-before-broome-helicopter-crash/12443298

[Twist & Shout]

Frightening

https://www.atsb.gov.au/media/news-items/2020/r44-accident-update/


https://www.atsb.gov.au/publications/investigation_reports/2020/aair/ao-2020-033/

[gulliBell]

If the TRDS disconnected or the TRGB fell off, I'm surprised at the amount of damage to the TR blades. Virtually a brand new helicopter. The POH says "Hover helicopter close to the ground to verify problem is resolved" but it seems from the preliminary report that only a vibration check and visual inspection on the ground was performed.

[[email protected]]

What on earth would possess you to take children airborne in a helicopter that had clear vibration issues through the pedals until you were absolutely sure that the problem had been fully investigated and rectified?

A dynamic balance on the ground doesn't replicate the stresses of flight conditions.

[Bell_ringer]

Grounding an aircraft was probably too expensive. Easier to risk lives and hope for the best.
No wonder they can’t shake the reputation, yes, yes, its not the aircraft’s fault :mad: blah blah.

[Fareastdriver]

A dynamic balance on the ground doesn't replicate the stresses of flight conditions.

How else are you going to do it?

Grounding an aircraft was probably too expensive. Easier to risk lives and hope for the best.

The engineers did their best and passed it as fit to fly. The pilot accepted it on the basis that he trusted his engineers.

I feel sorry for the bloke that signed it off.

[Bell_ringer]

From the loss of life, I doubt anyone did their “best”, as harsh as that may sound.

[wrench1]

From the loss of life, I doubt anyone did their “best”, as harsh as that may sound.
What we don't know is if the maintenance performed corrected the imbalance and subsequent vibration in the pedals. Until they determine the failure sequence of the T/R Assy, it's quite possible those engineers did exactly as they were required to do. As to signing off something then have a fatal accident, I would not wish that on any mechanic/engineer as it is the most sickening feeling out there. Sometimes catastrophic failures hide behind the most routine types of discrepancies....

[CGameProgrammerr]

You guys seem to be making the mistake of thinking the tail rotor was out of balance. Nowhere in the report does it say that. Instead, the mechanics assumed the vibration might have been due to an unbalanced tail rotor so they checked its balance and found it to be within limits. Something else was obviously catastrophically wrong with the tail rotor, shaft, or gearbox, which nobody bothered to check.

[rotormatic]

You guys seem to be making the mistake of thinking the tail rotor was out of balance. Nowhere in the report does it say that. Instead, the mechanics assumed the vibration might have been due to an unbalanced tail rotor so they checked its balance and found it to be within limits. Something else was obviously catastrophically wrong with the tail rotor, shaft, or gearbox, which nobody bothered to check.

https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/b1400c9f67bf3f828625854d0042cd8e/$FILE/2020-08-10.pdf

[Ascend Charlie]

To a non-mechanic's eye, the whole gearbox appears to have rotated 90 away from its position, one of the blades has hit the fin and been smashed and bent, then the whole rear end fell off in 3 bits?

[wrench1]

You guys seem to be making the mistake of thinking the tail rotor was out of balance. Nowhere in the report does it say that. Something else was obviously catastrophically wrong with the tail rotor, shaft, or gearbox, which nobody bothered to check.
Curious. How do you know "nobody bothered to check" everything? The report doesnt state that either. Considering they have video of the failure, I'm sure we'll know soon enough. Unfortunately, in my experience, catastrophic failures usually dont give you a 2 minute warning prior to failure, especially if he took off with no vibrations.

[gulliBell]

To a non-mechanic's eye, the whole gearbox appears to have rotated 90 away from its position, one of the blades has hit the fin and been smashed and bent, then the whole rear end fell off in 3 bits?
It looks like the TRGB rotated down whilst under power, both TRB whacked the lower fin cutting clean through the outboard one third of both blades. Pilot report of "tapping" in the pedals is not suggestive to me of an imbalance vibration condition. Rather, something was loose or cracked back there and flight loads were feeding back through the pedals as whatever it was that was loose was knocking or tapping in flight. High power take-off and something back there finally broke, quite possibly the TRGB mounting hardware.

[blakmax]

Some similarities with the crash of DQ-IHE. Vibrations, MRB rebalance, then blade failure leading to MRB impact on boom, although the boom did not completely separate. One blade was severed at approximately the same location as this case.

I am not a pilot, but I am curious to know if it is possible to differentiate between MRB vibrations and TR vibrations?

Regards

Blakmax

[industry insider]

In this case the reported tick vibration wouldn’t indicate an out of balance tail rotor to me. Out of balance is normally much more of a buzz through the pedals.

A simple dynamic balance for the reported problem doesn’t seem like the correct maintenance action.

[gulliBell]

...but I am curious to know if it is possible to differentiate between MRB vibrations and TR vibrations?

Yes, easy to differentiate between the two. A TR vibration is high frequency felt in the pedals. A MRB vibration is not high frequency and is not felt in the pedals.

[gulliBell]

..A simple dynamic balance for the reported problem doesn’t seem like the correct maintenance action.

I agree with all of that.

[[email protected]]

FED How else are you going to do it? A hover track and balance would be a good start.

If they don't do that on Robbies then the pilot should at least have done a hover check and handling check without pax since he had previously felt the vibration and would instantly know if it was still there.

The old adage of 'If you think Flight Safety is expensive, try having an accident' seems to hold here - very sadly. All for the sake of a check test flight it would appear.

Perhaps he was satisfied that the problem had been reported, the engineers had done some engineering and signed it off so therefore it must be OK...............

[industry insider]

Crab

If they don't do that on Robbies then the pilot should at least have done a hover check and handling check without pax since he had previously felt the vibration and would instantly know if it was still there.

I agree, although the failure may still have happened, but the pilot would have been the sole occupant. A vibration, noise or anything strange from the back end of a helicopter that isn't a simple TR vibe issue warrants a grounding and a thorough investigation before next flight in my view.

[JohnDixson]

GB: Yes, easy to differentiate between the two. A TR vibration is high frequency felt in the pedals. A MRB vibration is not high frequency and is not felt in the pedals.

Yes ....and possibly not. Not all main rotor induced vibes are 1P. Example: 4P main rotor on the S-70 is 17.6 hz while the tail rotor 1P is 19.8 hz. Hard to differentiate those two frequencies. It would help if only the pedals were shaking, but thats not always the case. The vib gear eliminates the doubt.

[kansarasc]

As a owner of new R44 this is very concerning to me. I believe that complying with FAA AD for checking cracks in TR blades would not have prevented this from happening. Looking at the pictures it looks like TR blade separation was secondary to something else. Very curious to find out the final conclusion by ATSB.
Since the owner of the company/helicopter himself perished in the accident I do not believe that neglected maintenance to save few bucks would have been an issue. What else a pilot can do other than report discrepancy to mechanic and go flying when he/she says everything is good.
BTW the date of AD is May 2020 and mine has completion date by manufacturer as June 19 2020. I am hoping they not only complied with AD but installed the blades with corrected design

[wrench1]

. A vibration, noise or anything strange from the back end of a helicopter that isn't a simple TR vibe issue warrants a grounding and a thorough investigation before next flight in my view.
Has any info come out that says the vibration was still present after the maintenance was performed? Or was the vibration corrected by maintenance then the failure happened?

[wrench1]

What else a pilot can do other than report discrepancy to mechanic and go flying when he/she says everything is good.
Depends. Personally, I wouldn't release the aircraft without knowing what was causing the vibration. But if the vibration was corrected by the engineers, i.e., no vibration felt prior to this flight, then one would assume the disc was fixed. Until we know this part, it will remain a guessing game. Some seemingly routine discrepancies end up leading to unforeseen failures, like in one case where a random xsmn chip light led to the loss of the upper xsmn case and rotor system in flight. No one saw that coming either.

[Bell_ringer]

Since the owner of the company/helicopter himself perished in the accident I do not believe that neglected maintenance to save few buck would have been an issue. What else a pilot can do other than report discrepancy to mechanic and go flying when he/she says everything is good.

According to the report he had sold the business and was finishing a year of agreed service as part of the sale.

If an aircraft develops such a sudden and severe anomaly in the tail, it warrants a thorough inspection.
It will be a tough sell convincing anyone that a quick ground balance check meets that requirement.
That it all ended in tears soon after the first takeoff doesn't instil confidence that end-to-end checks were thorough enough.
It remains to be seen if the aircraft was actually flight tested subsequently or was just signed off on a nod and a wink.

[Fareastdriver]

no vibration felt prior to this flight, then one would assume the disc was fixed.

He could well have done a vibration check in the hover before he departed and found it satisfactory. We will never know until one of the survivors recalls what happened.

[ring gear]

You are right JD. There are a plethora of vibes in helos. Often a cause of much confusion. If anybody would like a "quick & dirty" have look a the link......it may help. Work you way down through the full gambit of helo vibes on the page and see if it helps:

https://www.rwas.com.au/rtb/?preview_id=122&preview_nonce=62e5dd904a&preview=true

[JohnDixson]

RG, thanks, but a message saying I was not allowed to view drafts was all that presented itself. No worries: I had 39 years of chasing vibrations of all sorts. Unless you have discovered and are absolutely certain of the source, and confirmed that it cannot mutate to something more serious, it is a subject not to be put off.

[roscoe1]

To my mind, it is unimagineable that multiple people reported unusual vibrations and it would seem a cause was not determined yet they continued to fly the aircraft. The investigation will of course find if this is the case or not. To suggest that it was a company with a good record, that they did a ground run with their balancer and found no vibration seems to belie any good practices that may have happened here. If, it turns out that they performed in flight track and balance, well, that mitigates my issue with this but even if so, a vibration with no obvious cause is just the kind of thing that pops up when people talk about how important safety is.

In 35 years of working on helicopters, of all sorts, I have seen several instances where the time was spent, the money was spent and the company bore the brunt of inconvenience to figure out wtf was going on when a pilot comment might have been as vague as " it just feels different". On some occasions it was something innocous like a loose piece of equipment ( not that that would always be innocous) but on several other occasions it was a hair raising discovery, resulting in copious amounts of beer and pats on the back after it was discovered and fixed.

Needles to say ( although apparently not really), it appears that something other than an assumed out of track or balance t/r was at work here but the assumption may have been made akin to " well, it can't be anything else and running on the ground is the same as running in flight" (not). Sometimes it takes an adamant pilot willing to risk their employment but wishing to fly another day, a mechanic who has time on their hands and likes a puzzle or an owner/operator who "gets it". Whatever it takes, doing the right thing is better than pieces flying around and the misery of an accident. This seems like one of those accidents that will ultimately have a well defined cause and explanation and I hope I am wrong about what "may" have happened here.

[kansarasc]

but on several other occasions it was a hair raising discovery, resulting in copious amounts of beer and pats on the back after it was discovered and fixed.

.

Examples ? specifically for R44
just curious as a new owner to look for hidden monsters

[roscoe1]

Not too much on R22 during my time working on them. One cracked t/r flex plate just aft of clutch sheave, pilot noted clutch engagement time had changed by a couple of seconds. Might have been normal belt stretch but it made me look. Multipe sticking exhaust valves found over time, found due to change in mag drop, ignored by some, reported by one. Both were many moons ago.

[Paul Cantrell]

Sometimes it takes an adamant pilot willing to risk their employment but wishing to fly another day.

Reminds me of the day I was walking through our shop and was talking with one of the guys about a customer machine ( R44 ) he was working on. He had a component of the rotor head apart ( I'm trying to be a bit vague here on purpose ) and I mentioned my surprise that a particular part had a tapered bolt in it. I couldn't see any reason such a part would be designed that way. I was informed that it was not supposed to be tapered, it had just worn that way! 50% of the bolt was missing at the most worn position.

The story is that the ( young, probably first real job ) pilot complained about the flying characteristics, his company flew in a couple of ( A Star ) mechanics who looked it over and gave it a clean bill of health. The pilot, junior as he was, was smart enough to demand someone with extensive experience in type look at the ship, thus our involvement and discovery of the worn component.

There's no doubt in my mind that the bolt failing would probably have been fatal. I was, and still am impressed that the junior pilot would stand up to the company on that issue. A lot of people, especially at the start of a career, are not going to push back when a couple mechanics have declared a machine safe to fly.

He probably saved his own life, or the next guy who flew that machine.

[Paul Cantrell]

Since the owner of the company/helicopter himself perished in the accident I do not believe that neglected maintenance to save few bucks would have been an issue. What else a pilot can do other than report discrepancy to mechanic and go flying when he/she says everything is good.

I disagree with both of these statements. Look, nobody is going to dispatch a machine they know is going to crash. But people have an amazing ability to rationalize situations so that they can tell themselves that although it isn't right, that it will be okay. Owners can be the worst in this sense, because they tend to be the one hurt economically when the machine is grounded, but pilots and mechanics are guilty as well. We pilots want to go flying! And vibrations are the worst because we can be more or less sensitive to vibrations on different days ( like on windy days versus smooth days ). And vibrations, while arguably the hardest to quantify, can also be indicative of the most dangerous problems. A blade that can be balanced but is soon vibrating again can be indicative of a cracked blade. Vibrations from transmissions... Well that doesn't even need to be mentioned how serious that can be. And yet, what do all helicopters do? Vibrate! It can be difficult to determine which are the normal vibrations, and which are indicative of the problem that is about to kill you.

What else can a pilot do when they feel something isn't right, but the mechanic says it's fine? Lots ( depending on your situation ). I've called both Bell and Robinson myself when I've been unsatisfied with what the maintenance people are telling me. The technical support people can give you ideas about what might be wrong, as well as things you might try to further diagnose the problem. Also, having a senior person with lots of time in type fly it can help validate ( or repudiate ) what you think you're feeling. I'm not talking about the local CFI although they can be helpful, I'm talking someone with over a thousand hours in type... They can often pick up on smaller anomalies that a less experienced pilot won't.

I was flying with one client in an R44 and I could tell there was a subtle engine problem... we were pulling just a little too much power and there was a tiny but detectable torque kick in the hover. I told them to get it checked, but the maintenance shop said there wasn’t a problem. The next time I flew it, the problem was worse, but they still couldn’t feel what I was feeling. I told them to take it back to the shop and insist that the shop look further. Sure enough an exhaust valve was sticking. Nothing that would take you out of the air, but the point is that someone with a lot of time in type will be able to detect things ( and often know the cause ) that a less experienced pilot won’t even feel. It’s good to have access to someone like that when you aren’t sure about something. Even better is someone that can work with the maintenance people to figure out what is wrong.

Another issue you may encounter as someone who only flies one particular aircraft ( not type, but one particular aircraft, like a private owner tends to do ) is that you will just accept that a machine flies a certain way. I had a different client with an R44, and I could tell that there was a rigging issue from the way the machine did hover autos and touchdowns. The owner just accepted it because it was the only aircraft he regularly flew. I worked with the mechanic and we determined that the swashplate was grossly misrigged when it was overhauled ( by someone who didn't know what they were doing, based on all the other problems we found, in this case mounting the swashplate in the wrong location! ). It wasn't really a safety issue in that it wasn't going to come apart or anything, it just couldn't do a hover auto from more than 2 feet, versus the 5-6 feet of a normal R44, let alone do good touchdown autos. If you didn't fly other aircraft of the same type, you might just think that's how R44s did autos...

You should try to emulate the helicopter pilots Harry Reasoner ( the TV reporter ) was describing when he said:

"This is why being a helicopter pilot is so different from being an airplane pilot, and why in generality, airplane pilots are open, clear-eyed, buoyant extroverts, and helicopter pilots are brooding introspective anticipators of trouble. They know if something bad has not happened it is about to."

[CGameProgrammerr]

Heilcopters vibrate but the pedals do not vibrate at all. The pilot reported feeling vibration in the pedals which is very unusual.

[kansarasc]

I

"This is why being a helicopter pilot is so different from being an airplane pilot, and why in generality, airplane pilots are open, clear-eyed, buoyant extroverts, and helicopter pilots are brooding introspective anticipators of trouble. They know if something bad has not happened it is about to."

Like this.
I think I am undergoing that transformation right now

[gulliBell]

Heilcopters vibrate but the pedals do not vibrate at all. The pilot reported feeling vibration in the pedals which is very unusual.
Not correct at all. The pilot reported a tapping in the pedals, not a vibration. Fundamental difference.

[Twist & Shout]

How else are you going to do it?



The engineers did their best and passed it as fit to fly. The pilot accepted it on the basis that he trusted his engineers.

I feel sorry for the bloke that signed it off.

A lot of posters are talking about the helicopter being “signed out” or “ok’d” by the engineering staff.
No mention of this in the report.
Just saying...

A pilot who flew the helicopter on 2 July 2020 to Broome Airport reported feeling unusual vibrations through the tail rotor pedals. He described it as if something was repetitively tapping through the pedals. The pilot of the accident flight also conducted a short flight in the helicopter and confirmed the unusual vibrations.

Maintenance personnel conducted a dynamic tail rotor balance on 3 July 2020 (the day before the accident). The dynamic tail rotor balance was found to be within limits, and the maintenance personnel could not detect any unusual vibration on the ground.
The accident flight was the first flight since the maintenance was conducted. Overall, the helicopter had 291 recorded hours in service.


Also from the report:


The R44 Pilot’s Operating Handbook (POH) includes the following 'safety tip':

A change in the sound or vibration of the helicopter may indicate an impending failure of a critical component. If unusual sound or vibration begins in flight, make a safe landing and have the aircraft thoroughly inspected before flight is resumed. Hover helicopter close to the ground to verify problem is resolved, and then have aircraft reinspected before resuming free flight.

The ATSB strongly endorses this advice, and urges any R44 pilot that experiences unusual vibrations through the tail rotor pedals to land as soon as possible and follow the advice in the POH safety tip.


My BOLD in the quotes of report.

[CGameProgrammerr]

Not correct at all. The pilot reported a tapping in the pedals, not a vibration. Fundamental difference.
The report clearly says both, and both are extremely abnormal.

[ericferret]

A lot of posters are talking about the helicopter being “signed out” or “ok’d” by the engineering staff.
No mention of this in the report.
Just saying...



Also from the report:

The difficulties in fault finding should not be underestimated, certain vibration and control faults can be difficult to isolate..

We had a 365 which was reported as having a slight kick in yaw on the ground and in the air. Much fault finding of the yaw system ensued with no answer.
Two of us after discussing it decided to take a new tack.
Kick on the ground, nosewheel castoring bearing had a hard spot.
Kick in the air, roll actuator problem.

My favourite
Aircraft shaking on the ground.
Main rotor balancing and structural inspections followed by undercarriage parts replaced. No improvement.
Watching the aircraft ground running from a slightly raised location the engineer with me said, " It looks as if it is in negative pitch"
We checked the rigging and the blades were about 2 degrees below allowable min pitch.
Airtested and pilot returned saying that was much better.
Vibration gone?
Yes and now you dont have to fly it with the collective under you arm pit.

Speechless.

[rotormatic]

Unusual vibrations can be mysterious and hard to find sometimes..... had a hiller that had a high freq one time when it was on a trailer. Spent a couple of days changing tail rotor system components, and found the freq was caused by the thing being on the trailer.... live and learn.

[industry insider]

Another issue you may encounter as someone who only flies one particular aircraft ( not type, but one particular aircraft, like a private owner tends to do ) is that you will just accept that a machine flies a certain way.

Very true, I have seen it many times.

[John R81]

But on the up-side, flying the same aircraft means that you do spot when something changes.

Some years back was once in an R44 with another pilot on climb-out when there was a solid loud metallic "thud" (like someone dropped a bag of tools in the rear footwell). Nothing more, no vibration or loss of power - all smooth. We looked at each other, and agreed immediate return. Engineering inspection followed but couldn't find a fault, told to hover it "heavy" to see if it would repeat. 15 min and no repeat, aircraft released to service but not with me in it. A couple of days later another pilot with commercial passengers onboard experienced the same "thud" in level flight. Made a PAN call and landed, aircraft recovered by road followed by head-scratching in engineering. Someone suggested looking at the Sprag Clutch, which requires disassembly and most shops cannot do. When disassembled it was destroyed internally - fault found.

Taught me one thing, if something strange happens and they can't find the fault, then the fault is still there.

[Droop Snoot]

In this case the reported tick vibration wouldn’t indicate an out of balance tail rotor to me. Out of balance is normally much more of a buzz through the pedals.

A simple dynamic balance for the reported problem doesn’t seem like the correct maintenance action.


In addition to directly addressing the discrepancy, "Conditional Inspections", in AMM Chapter 5, should be consulted during non routine maintenance. This data includes

hypothetical and known causes of specific symptoms experienced by the flight crew or observed by others
potential hidden effects of flight envelope exceedances or other unusual events that occurred in flight or on the ground
actual root causes specific to the aircraft type in question, which is added to the manual as service experience is accrued

DS

[industry insider]

John R81 wrote

But on the up-side, flying the same aircraft means that you do spot when something changes.

Not always if the change is gradual. Before the days of HUMS, I visited a base where one crew flew the same aircraft everyday. They were both very professional and were fussy about the state of the aircraft. I performed a line check on one of the crew and thought that the aircraft was a bit rough compared with the last time I had flown it a month prior. A track and balance showed it was close to the limit and had deteriorated, but the crew which flew it every day hadn't noticed.

[Twist & Shout]

Minor vibration changes can be difficult to pick up for many pilots, including me.
If the change is slow, and over a long period, even more so.

It’s “thread drift” here though. Vibes/tapping were reported by one pilot, confirmed by another. An out of balance TR was then eliminated as a source.
The RFM call’s for a low hover, followed by a shut down and re-inspection. (Assuming the Vibe was no longer present in the low hover)
Rather than the above procedure, the report seems to indicate, that pax were loaded for what was essentially a maintenance test flight.
Am I missing something?

[[email protected]]

Twist and Shout - I read it the same way as you.:ok:

[heliduck]

John R81 wrote



Not always if the change is gradual. Before the days of HUMS, I visited a base where one crew flew the same aircraft everyday. They were both very professional and were fussy about the state of the aircraft. I performed a line check on one of the crew and thought that the aircraft was a bit rough compared with the last time I had flown it a month prior. A track and balance showed it was close to the limit and had deteriorated, but the crew which flew it every day hadn't noticed.

This is a common phenomenon with human performance - “The boiling frog is a fable describing a frog being slowly boiled alive. The premise is that if a frog is put suddenly into boiling water, it will jump out, but if the frog is put in tepid water which is then brought to a boil slowly, it will not perceive the danger and will be cooked to death.“

[Fareastdriver]

That's what happens with prawns when you buy them on the hoof.

[industry insider]

Preliminary report is out. Not conclusive yet.

https://www.atsb.gov.au/publications/investigation_reports/2020/aair/ao-2020-033/

[[email protected]]

Very concerning though that an aircraft could suffer what seems to be a catastrophic failure immediately after being inspected, and essentially given a clean bill of health - notwithstanding the engineer requiring a test flight - and that the maintenance pilot thought the site unsuitable for a check flight, leaving it for someone else to do even though the site was unsuitable.

[catseye]

And look at the total hours on the airframe. Glad I don't get into Robbo's

[Vertical Freedom]

And look at the total hours on the airframe. Glad I don't get into Robbo's

Welcome to the sad world of Robinson’s .....just part of the course; bits flinging off & failing on a frighteningly regular basis :ugh:

:eek::{:yuk:

[Twist & Shout]

Very concerning though that an aircraft could suffer what seems to be a catastrophic failure immediately after being inspected, and essentially given a clean bill of health - notwithstanding the engineer requiring a test flight - and that the maintenance pilot thought the site unsuitable for a check flight, leaving it for someone else to do even though the site was unsuitable. With unsuspecting passengers.

[aa777888]

Welcome to the sad world of Robinson’s .....just part of the course; bits flinging off & failing on a frighteningly regular basis :ugh:

:eek::{:yuk:

Yes, everyone knows I would be quick to respond to this, so without further ado...

VF, your statement is utter rubbish. If we assume that this event was caused by a catastrophic failure of some component (a fair assumption IMHO, although we may all yet find out differently in the end), such events are exceedingly rare in any make/model of helicopter, including Robinsons, and yet by no means unique to any one make/model helicopter, including Robinsons. It is trivially easy to demonstrate this. A 30 second Google search brings up this gem: https://tsb-bst.gc.ca/eng/rapports-reports/aviation/2011/a11o0205/a11o0205.html An in-flight main rotor blade separation on a 206. Can you believe it, the venerable 206? Yes, we better stop flying all those, too! And with reference to another, similar incident on a 206 in the same article. Coming at it from the other direction, a search of the NTSB accident database will clearly demonstrate that bits do not fall of Robinson helicopters with any more or less frequency than any other type of helicopter. We've done that study to death (http://www.pprune.org/rotorheads/600303-another-robinson-crash-4.html) on PPRuNe and yet you refuse to accept it because you lost someone close to you in a Robinson accident that you can't explain so you will forever blame the design and the company even though the statistics don't support your position.

Meanwhile, while remaining intellectually interested in the root cause of this accident, I don't worry so much because once is happenstance, twice is coincidence, but three times is enemy action, and we have never seen, and are not yet seeing, an epidemic of R44s shedding their tails in dramatic fashion. And if we did see it it would probably happen in one of those countries where they regularly and inappropriately thrash the bejeezus out of their R44s first, thus giving the US aviation community a chance to head off any incipient problems. Of course this is all very idle speculation in the best PPRuNe style.

[nomorehelosforme]

[QUOTE=aa777888;10877530]Yes, everyone knows I would be quick to respond to this, so without further ado...


Here we go again.....

[Bell_ringer]

Welcome to the sad world of Robinson’s .....just part of the course; bits flinging off & failing on a frighteningly regular basis :ugh:

:eek::{:yuk:

It’s not that robbies cleanse the gene pool, they unfortunately encourage punters who don’t know better to join them.strangely enough the Robbie cult are always surprised when it happens.

[capngrog]

It looks like the aft tail cone separated cleanly. Is there a production break at that point? Is the damper bearing located in this area?

I don't know much about the R-44, but I was wondering what would cause such a clean break in the tail boom structure as shown in the ATSB Preliminary Report.

Regards,
Grog

[[email protected]]

Some helicopters are prone to dynamic rollover, some helicopters have low inertia rotors that are unforgiving to slow reaction to engine failure, some helicopters are prone to mast-bumping, some helicopters find it easy to chop off the tail, some helicopters are very vulnerable in turbulence and some helicopters have extra speed limitations placed on them by manufacturers safety notices.

But I wonder which make manages to encompass all these flaws..............

[aa777888]

And yet those helicopters don't crash or kill people any more often than Bell helicopters. Got the numbers to prove it. Shared them here in the link above.

I don't enjoy fighting with you...gents, but I think its important for the facts to come out so that some, poor, unsuspecting reader of these forums doesn't automatically think that Robinson helicopters are death traps, at least not without rejecting the objective evidence first, like some people do.

[gulliBell]

I'm with VF on this one. Crab summed it up quite well without actually saying what many of us here are thinking. You'll never see me in one of those flimsycopters.

[MickG0105]

And yet those helicopters don't crash or kill people any more often than Bell helicopters.

Well that's highly debatable as the following graphic from this article (https://www.latimes.com/projects/la-me-robinson-helicopters/) illustrates. The graphic shows that the Robinson R44 led all major models with the highest fatal accident rate per flight flight hours for the period from 2006 to 2016 based on NTSB and FAA data.


Death rate (Fatal accidents per 100,000 flight hours)

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/2000x1190/la_me_g_robinson_heli_death_rates_dt_dd13fa8e44e8fdd2aeaa497 7a959e403e057da16.png

Now, there could be a variety of factors other than the helicopter itself that skews the data against the Robbies. However, given that the R44 has a nearly 60 per cent worse fatality rate than the average of the next five non-Robinson helicopters it certainly looks like the helicopter itself is a factor.

For balance, there's this article (https://airfactsjournal.com/2019/01/whats-wrong-with-robinson-r44-pilots/) by John Zimmerman that makes a counter-argument based on fatal accidents per fleet size (as opposed to hours flown). When you look at ATSB and CASA data for Australia you see a not dissimilar outcome for fatal accidents per fleet size when comparing Robinsons with Bells; the number of fatal accidents per number of helicopters is comparable.

What is immediately apparent, however, once you dive below the headline numbers is that you do not see 'loss of control' and/or 'in-flight break-up' in the Bell column; those causes are almost uniquely attributable to Robinsons. That is surely telling.

Got the numbers to prove it. Shared them here in the link above.
You provided two links above - one was to a page that doesn't exist and the other was to a 206 accident investigation.

[Nescafe]

But I wonder which make manages to encompass all these flaws...

If it was a cake, you'd have changed the recipe by now.

[aa777888]

The link worked when I posted. How it became broken I can't say. It's fixed now. The LA Times article is debatable. The fatal accident totals are accurate (they are US-only numbers). But the hours by make/model are questionable. As an owner, I've never returned a FAA flight hours survey, much like a lot of other folks, and there is no way those hours are correct. I'm impressed they were able to get the hours. I tried hard and couldn't get them from the FAA broken down by make/model. Assuming they actually got real numbers and it's not all BS. Zimmerman's article is much more realistic.

As for cake recipes, the R44 is rapidly becoming the most popular helicopter of all time. Over 6300 built to date and poised to eclipse the 7300 206's that have been built. Pretty tasty to a lot of people. That it takes more care to fly it safely I'll be the first to admit. But it's not the train wreck that everyone makes it out to be. If you fly it by the book. There are far too many who don't.

[industry insider]

As for cake recipes, the R44 is rapidly becoming the most popular helicopter of all time. Over 6300 built to date and poised to eclipse the 7300 206's that have been built. Pretty tasty to a lot of people. That it takes more care to fly it safely I'll be the first to admit. But it's not the train wreck that everyone makes it out to be. If you fly it by the book. There are far too many who don't.

I will leave you to enjoy it. I won't be straying downwards from a 206.

[Twist & Shout]

If we are talking about this particular crash, the one in the thread title.
The AC gave a clear warning. The flight manual was ignored. The maintenance engineer was ignored. The helicopter eventually failed. (In a way I haven’t heard of before)

Or we can “Robinson bash/defend”, which is basically just everyone reinforcing their current view. Pretty boring stuff.

[John R81]

If we are talking about this particular crash, the one in the thread title.
The AC gave a clear warning. The flight manual was ignored. The maintenance engineer was ignored. The helicopter eventually failed. (In a way I haven’t heard of before)

Or we can “Robinson bash/defend”, which is basically just everyone reinforcing their current view. Pretty boring stuff.

:D:D:D

Not sure that any make / model machine would treat you different, given the sequence above.

[Bell_ringer]

Not sure that any make / model machine would treat you different, given the sequence above.

It's not the sequence that is the issue, it is the operational and safety culture that seems to be disproportionately aligned against lower-cost operators associated with this specific brand, particularly where the quality of components leaves something to be desired.

[John R81]

Bell Ringer

Classic thread drift. Better to post those views on the Robbie page, this one is about the crash at Broom.

[Bell_ringer]

Classic thread drift. Better to post those views on the Robbie page, this one is about the crash at Broom.

The tail separating wasn't the cause of the accident, that just defined the outcome.
The accident started on the ground some time before.
While incomplete, the report doesn't paint a great picture of the operator, so it's not so much drift as a subtle yaw.

[wrench1]

Will be interesting to know if the T/R D/S bolts were checked at the G/B flex plate. The T/R shaft has a number of rotational scores/scratches just forward for the flex plate mount as does the interior of tailcone bulkhead at the upper inspection hole. While I don't agree it was given a "clean bill of health" due to the requirement of a check flight, there are still a number of questions left unanswered at this point. And just as discussed in the Bahama Cline 139 accident, yet again we have another pilot who defies logic, plus the actions of the previous pilot, and loads his family up for a maintenance check flight. As the rotor turns....

[wrench1]

I was wondering what would cause such a clean break in the tail boom structure as shown in the ATSB Preliminary Report.
FYI: The "clean break" is where the ATSB more than likely removed the tailcone. The accident photos show the tailcone still on the aircraft.

[gulliBell]

I find it incredulous there was no maintenance assessment flight after the maintenance was conducted. Only a ground run was performed.

[aa777888]

FYI: The "clean break" is where the ATSB more than likely removed the tailcone. The accident photos show the tailcone still on the aircraft.
Link to photo for convenience: https://www.abc.net.au/cm/rimage/12443418-3x2-xlarge.jpg?v=3


https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/862x575/12443418_3x2_xlarge_d4ce46d22ca913d04617304244cd0af759f117be .jpg

[CGameProgrammerr]

Regarding Robinson statistics, one thing to keep in mind is the vast majority of private helicopter owners own a R44, with most of the remainder owning a R22. The others, especially all of the turbines, are almost entirely owned and operated commercially.

[capngrog]

Link to photo for convenience: https://www.abc.net.au/cm/rimage/12443418-3x2-xlarge.jpg?v=3


https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/862x575/12443418_3x2_xlarge_603dc712612206c1157d1805539628b264e786e5 .jpg


Thanks for that photograph: it certainly gives a bit more information on the crash than just photos of various bits. It looks like the helicopter hit on its right side while yawing to the left, yet the Robinson rotor system as viewed from above rotates counter-clockwise (as do most American designs), which upon loss of tail rotor authority would induce a yaw to the right. Or am I missing something again? Was the tail rotor drive train damage pre or post impact?

Regards,
Grog

[212man]

Thanks for that photograph: it certainly gives a bit more information on the crash than just photos of various bits. It looks like the helicopter hit on its right side while yawing to the left, yet the Robinson rotor system as viewed from above rotates counter-clockwise (as do most American designs), which upon loss of tail rotor authority would induce a yaw to the right. Or am I missing something again? Was the tail rotor drive train damage pre or post impact?

Regards,
Grog
Have you read the report? It clearly states the afte tail cone, TGB and empennage detached during departure, the aircraft descended yawing rapidly to the right, and impacted on its right side.

[wrench1]

It looks like the helicopter hit on its right side while yawing to the left, yet the Robinson rotor system as viewed from above rotates counter-clockwise (as do most American designs), which upon loss of tail rotor authority would induce a yaw to the right. Or am I missing something again? Was the tail rotor drive train damage pre or post impact?
As mentioned, the missing parts in the accident picture departed the aircraft in flight which tends to cause severe control issues due to the loss of weight/thrust at such a long arm. How it ended up on the right side is probably more based on chance than any "controlled" effort. A number of helicopters that lose the entire backend tend to roll inverted depending on internal loading. What caused the T/R assy and fin to depart has still not been determined.

[capngrog]

Have you read the report? It clearly states the afte tail cone, TGB and empennage detached during departure, the aircraft descended yawing rapidly to the right, and impacted on its right side.

I apparently failed to clarify the source of my confusion. In the subject photograph, the aft end of the tail boom is bent to the left, which would indicate a left-hand rotation of the fuselage as it impacted on its right side. I did read the report, and do not doubt that the helicopter rotated violently to the right after the loss of its tail rotor and associated hardware. I'm sure someone on this Forum can explain this apparent (to me anyway) contradiction.

Any way, back to the question at hand. I read with interest the FAA Airworthiness Directive (effective 22 May, 2020) concerning cracks found in the tail rotor blades of certain R-44 and R-44II helicopters. The AD indicated that it was believed that: "The cracks were caused by high fatigue stresses due to resonance when the blades were at high pitch angles from large left pedal inputs." I did not see any mention of this AD in the ATSB Preliminary Report. I'm not sure how long or for how many hours the owner of the accident helicopter operated it out of the industrial estate on the north side of Broome, but from looking at the ATSB Preliminary Report, it could have been for as much as 40 hours or so. It was reported that operating out of the industrial estate required a steep if not vertical departure, which would have required a lot of power and a lot of left pedal to counter act the torque ... just the thing that may have caused the TRB cracks described in the AD. Loss of even a portion of a tail rotor blade would have resulted in severe imbalance, possibly involving forces sufficient to cause separation of the tail rotor gear box. The ATSB report described their examination of the tail rotor gear box, and no defects were detected.

Tail rotor blade loss may or may not have been instrumental in the cause of this crash. At this point, who knows for sure? It's a puzzler, and hopefully, the cause of the crash will be found before any further similar crashes can occur.

Regards,
Grog

[aa777888]

It does not take a lot of left pedal to make a maximum performance take-off in an R44.

[Bell_ringer]

It does not take a lot of left pedal to make a maximum performance take-off in an R44.

pistons rarely run out of pedal, torque isn’t in great supply.
they do regularly run out of horses tho.

[aa777888]

pistons rarely run out of pedal, torque isn’t in great supply.
they do regularly run out of horses tho.
Very true. I regularly wish that Robinson, who has an done an excellent job of embracing everything that both Garmin and Genesys Aero systems has to offer, still has not offered modern electronic engine instrumentation. I would very much like to see an FLI with audible warnings for approaching power limits, and for high rotor RPM. Low RRPM warning provisions are fine as is.

[Twist & Shout]

pistons rarely run out of pedal, torque isn’t in great supply.
they do regularly run out of horses tho.

Very true. I regularly wish that Robinson, who has an done an excellent job of embracing everything that both Garmin and Genesys Aero systems has to offer, still has not offered modern electronic engine instrumentation. I would very much like to see an FLI with audible warnings for approaching power limits, and for high rotor RPM. Low RRPM warning provisions are fine as is.

I disagree with the sentiment. It’s not unusual to have a “limit” that the pilot has to respect. An FLI simply combines several possible limits (NG, ITT/TOT, Torque for example) The “FLI” On an R44 is the MAP gauge. Of course the limit must be calculated for the atmospheric conditions.

The R44 has more installed HP than should be used at sea level.
Long before it “runs out of HP” (RRPM droop), the MAP limit has been ignored, and the drive train has been abused.

[Bell_ringer]

The R44 has more installed HP than should be used at sea level.
Long before it “runs out of HP” (RRPM droop), the MAP limit has been ignored, and the drive train has been abused.

Obvious statement. No aircraft will take itself outside of it's performance envelope.
When there is less headroom or margin for error then the possibility of an exceedance increases, more so when at altitude and warmer temps, especially if you didn't plan properly.
Many a robinson has lost its battle with gravity for this reason, all played out with that single note shriek from the panel.

Unfortunately the limit isn't always understood or respected, so perhaps making it more difficult for someone to be foolish isn't a bad idea.
Not that it is relevant to this accident.

[Robbo Jock]

Wonder if the TR flex coupling let go, that could have created an effective little circular saw inside the tailboom which would explain the fairly neat cut.

[aa777888]

The “FLI” On an R44 is the MAP gauge. Of course the limit must be calculated for the atmospheric conditions.Ridiculous. Guimbal did it right in the G2. I loved the FLI when I flew it. So much simpler and easier, and therefore safer, to manage engine power limits that way.

[ApolloHeli]

Ridiculous. Guimbal did it right in the G2. I loved the FLI when I flew it. So much simpler and easier, and therefore safer, to manage engine power limits that way.

You're right in saying that. It's actually called an "MLI" (Multiple Limit Indicator) in the Cabri, and it does a cracking job at showing you whether you're limited by torque or throttle and making it very clear to you when the helicopter is unhappy with what you're doing (I've typically seen the switchover from Tq limitation to Throttle at between 3000-4000ft depending on the weather). It's very useful when the atmospheric conditions are always changing (such as when you're climbing / descending), or crossing high terrain in the cruise (knowing how close you are to full throttle etc).

[capngrog]

Wonder if the TR flex coupling let go, that could have created an effective little circular saw inside the tailboom which would explain the fairly neat cut.
I agree that failure of the aft flex coupling could cause all sorts of havoc, but tail rotor blade failure is still my guess. Take a look at this photo from the ATSB Preliminary Report.

Well, I've not had much luck in posting photos in this forum, and I apologize for my inability to post photos. Just take a look at the report; however, the next paragraph should provide enough information, since it describes a related feature of the photograph.

A "Tail rotor blade section" was found approximately 100 meters south of the "tail rotor and gearbox" remains, which indicates an in flight break up to me. That plus the AD on tail rotor blade cracking indicate a possible in flight tail rotor blade failure. Such a failure would also account for the separation of the tail rotor and gearbox and the fragmenting of the aft bulkhead of the tailboom.

Just a thought, but it may be interesting to ask the pilot, who flew the helicopter and discovered the pedal "vibration" on his flight of 29 June, 2020, whether or not the vibration changed with right or left pedal movement.

Just my opinion.

Regards,
Grog

[aa777888]

If that turns out to be the root cause, this issue goes all the way back to 2012 when Robinson published service bulletin SB-83.

[kansarasc]

Since the TR was the focus of attention and experienced eyes were looking at it I doubt there was anything obvious which can be seen from outside was broken/loose/missing. I am guessing something inside the tail cone which was hidden from the view came off

[Ascend Charlie]

Wonder if the TR flex coupling let go, that could have created an effective little circular saw inside the tailboom which would explain the fairly neat cut.

Not so neat, look at the photo at #79

Yes the flex plate is visible, but that is just the shear point when the rest of the tail departed the scene.

[Twist & Shout]

Ridiculous. Guimbal did it right in the G2. I loved the FLI when I flew it. So much simpler and easier, and therefore safer, to manage engine power limits that way.

Because you “loved the FLI“ (which apparently is an MLI) when you flew the G2; me claiming that the MAP gauge in a Robinson indicates the first power limit is “ridiculous”?

Are you qualified to fly a helicopter?

Is English your first language?

[212man]

Because you “loved the FLI“ (which apparently is an MLI) when you flew the G2; me claiming that the MAP gauge in a Robinson indicates the first power limit is “ridiculous”?

Are you qualified to fly a helicopter?

Is English your first language?

I tend to agree. A turbine helicopter has three possible limits - Ng/N1, Tq and T5/T4/TOT/ITT Add another engine and borderline ambient conditions, and you could be hitting two different limits more or less together. E.g max Ng on one engine while max torque on the other (I’m mainly talking about take off or OGE hover).. This is when an FLI really comes into its own. How many limits are there on an SE piston aircraft? Observe MAP limit per placard and?

[aa777888]

Because you “loved the FLI“ (which apparently is an MLI) when you flew the G2; me claiming that the MAP gauge in a Robinson indicates the first power limit is “ridiculous”?

Are you qualified to fly a helicopter?

Is English your first language?
"Yes" to all three questions.

With respect to the first question, the point I was trying to make was that there should be automation associated with showing the pilot where the limits are and you didn't appear to agree with that position and, worse, you tried to equate a simple MP gauge with an FLI (or MLI, if you prefer). In both cases I find that ridiculous. That is a far cry from merely confusing a minor point of lexicon, i.e. FLI vs. MLI, both of which perform the exact same function: fully automating the process of indicating to the pilot how much power is being used, and how much power is left, before one or more applicable limits are exceeded, be it torque, time, temperature, pressure, etc.

[aa777888]

I tend to agree. A turbine helicopter has three possible limits - Ng/N1, Tq and T5/T4/TOT/ITT Add another engine and borderline ambient conditions, and you could be hitting two different limits more or less together. E.g max Ng on one engine while max torque on the other (I’m mainly talking about take off or OGE hover).. This is when an FLI really comes into its own. How many limits are there on an SE piston aircraft? Observe MAP limit per placard and?
Have you ever flown a piston helicopter? On both the Robinson and the Cabri, there are limits associated with manifold pressure, outside air temperature, time and available throttle.

On the Robinson the pilot must figure out what the manifold pressure limit is based on the current OAT. This is done by the crude method of looking at a table and interpolating the numbers (or just choosing the more conservative). The pilot must also keep track of time manually if using power in the 5 minute limit range (as determined by the aforementioned tabular lookup). On older Robinsons the table can be seen if you can crane your neck back far enough to see it on the overhead, and it's printed on the Robinson checklist card as well (or the POH if you really want to crack a book while flying). On newer Robinsons they place it on this cool little rotating cuff on the cyclic arm. And there is no indication of how much throttle you are using until you run out, something that can come as a surprise given the action of the throttle governor, unless you are in one of the newer serial numbers that has the "full throttle" indicator light (or an older one with that option, which seems to be a bit rare), which unfortunately gives you little warning of where you stand until you are standing there.

Contrast this with the MLI (see, I can learn ;)) on the Cabri, which takes all that into account and shows you continuously computed power in percent, with the 5 minute limit area being clearly designated by a yellow arc, and a convenient countdown timer when in the yellow arc. Plus the MLI conveniently switches between horsepower limited regimes and throttle limited regimes, the latter occurring at lower density altitudes, of course, thereby clearly indicating how much reserve remains in any situation.

Thus, while the limits and methods of measuring power differ in turbine and piston helicopters, they both can present sufficient complexity such that the presence of automation can be a significant boon to safe and easy operation. Certainly both types can be flown with round dial technology and rely more heavily on pilot computation, skill and attention, but better solutions are readily available nowadays.

[CGameProgrammerr]

There are two practical dynamic limits the pilot has to manage manually: map pressure and Vne. The latter also changes with temperature and altitude (and obviously other fixed factors) for reasons unrelated to the engine but it requires constant placard checks.

[Bell_ringer]

Don’t get it really.
For most use cases, the only place that MAP should be a problem is at lift and landing, both are known quantities.
There are more demanding use cases but in those instances your attention would be on avoiding trees and wires.
if power management is so demanding as to be a safety issue then that pilot shouldn’t be given a license.
there are way more complex variables and aircraft to manage and you can’t instrument-out stupid.

[212man]

Have you ever flown a piston helicopter? On both the Robinson and the Cabri, there are limits associated with manifold pressure, outside air temperature, time and available throttle.
Yes I have - thank you for asking. It didn’t have a governor either. I also learned to fly in variable pitch propellor FW, that also had MAP limits. But that was in an era where I was taught to set RPM by aural cues (then glance at gauge to confirm) and could set pitch and bank angles by looking out of the window (see other thread about how you don’t do this in an AW139 it seems).

Hey - I have seen the YouTube video explaining how the MLI works, and the cockpit displays look great (no dispute) and will reduce workload, but there is no getting away from the fact that the MAP is the FLI.

[Mutley1013]

A real thread drift going here, so in an effort to continue the direction, having a bunch of hours on the R22 and Cabri, aa777888 has it bang on and I am amazed at the level of (incorrect) vitriol coming his way. Just because a manual MAP lookup can be done (tricky in flight when conditions change), and has worked (most of the time) over the years, does not mean a simple, clear and dynamic display isn’t a better idea for everyone regardless of experience level. I have also flown in conditions (not even particularly unusual) where fuel flow was the limiting factor before MAP - not that I hit the limit, that would be poor form indeed.

Thinking about it, with Nav, I am sure everyone here can use a map, but isn’t a modern moving map display easier all round? Doesn’t mean someone isn’t worthy to fly - that would only be case if they couldn’t fly without a moving map.

[212man]

I think the word ‘ridiculous’ may have got people’s attention. Got mine.

[[email protected]]

So for the number of landings and take offs you are likely to do in a sortie, working out the MAP limits is too difficult and demanding and requires a digital display? How many of you are taking off and landing at vastly differing density altitudes on a regular basis in a Robbie?

Proper Pre flight Planning Prevents Piss Poor Performance - 7 Ps of aviation.

Cabri are obviously superior to Robbies if the MLI is so good.

[CGameProgrammerr]

Quite often in California actually, where I take off at 400', may eventually climb to 6000' en route due to mountains, and land at perhaps 2500' (Las Vegas) while temperatures are all over the place, cooler near the coast and very hot over the desert.

[aa777888]

I see lots of temperature variations when operating between sea level and 3 or 4 thousand feet (rarely get above that around here), or on a cross country that starts in the cool early morning then you start to see the heat of the day, or from inland to the shore or vice versa, etc., etc. Nobody said it was hard to manage, or do, or whatever, just that it would be easier and possibly safer if a machine did it for you. Just like it is on a turbine. And don't forget the throttle limit factor, hence an MP gauge cannot be an FLI, it does not account for that, even if you are willing to give it a pass as an FLI because you looked up the exact MP limits vs. temperature for that particular moment in time. And being able to understand your available throttle is a nice safety improvement.

Obvious troll, crab, no bite... :=

[[email protected]]

aa777888 - as others point out, MAP limits are only a real issue when taking off and landing - are you doing that at varying alts and temps or just cruising through?

The throttle limit is pretty obvious because if you keep pulling the Nr goes down.

Didn't think you'd want to admit to Cabri superiority:)

CCGame - If you don't know what the likely conditions are at your intended LS (you only need a phone to find out) what pre-flight planning are you doing? The conditions in Vegas are very predictable so not much thinking required.

You could have a copy of the MAP placard on your kneepad or even on the ubiquitous I-pad so why crane your neck?

How many owners would pay the extra on a Robbie for an MLI? And are they pestering Robinson to provide one?

Seems like a problem that doesn't need a solution, just a bit of planning required.

[Bell_ringer]

Seems like a problem that doesn't need a solution, just a bit of planning required.

Indeed.
Who spends their time staring at a panel or waiting for a caution to light so you can work out you are near a limit.
In the 2 hours or so that these aircraft can manage to fly, density conditions can only change so much.
You plan performance and loading for the highest and warmest condition in flight.
After that, fly with some accuracy, preferably into wind and the aircraft will perform as expected.

When the lever meets the armpit, an exceedance approaches.

[Sikpilot]

Wonder if the TR flex coupling let go, that could have created an effective little circular saw inside the tailboom which would explain the fairly neat cut.

I would think they could do metallurgy tests on the pieces and get pretty close to finding out what gave way first. Not sure if they will do that though.

[aa777888]

aa777888 - as others point out, MAP limits are only a real issue when taking off and landing - are you doing that at varying alts and temps or just cruising through?
Most of my flights lately are cross country. Interestingly, those are the flights that have peaked my interest in having an MLI or FLI even though it's a piston single. The quick hops are, as you say, not an issue, just figure stuff out for takeoff and landing. But I find when I am trying to make time and run MCP the entire way I keep a critical eye on things. For me it's not unusual to see a OATs variation of 10-20 degrees during cruise on a cross country flight, and elevation changes of 3000 feet or so. It's not just flat, boring terrain around here, it's mountains and seashores and everything in between. Yeah, it's only a difference of an inch or so on the MP limit, but again, it's a want, not a need, and electronic engine instrumentation is less expensive than separate gauges so why not? Bruno liked the idea, obviously, and I know you are all fans of Bruno!

The throttle limit is pretty obvious because if you keep pulling the Nr goes down.Now you are just being silly.

[CGameProgrammerr]

Map limits don't change drastically in flight but they do change; in my last flight there were times during cruise when MCP was 23+" and other times when it was 21". More relevantly though, Vne changed dramatically, from 130 kts at departure down to 103 kts when going over a mountain at high temperatures. I would absolutely pay extra for something that makes this easier to manage. I may even write my own Android app to show the current map/Vne limits, though I don't know how to feed it OAT so that may have to be selected onscreen (simple slider).

The ideal solution would be for the Garmin PFD to be programmed to change its yellow/red IAS arc dynamically based on conditions, because it does know OAT and altitude. (Pilot would have to remember the 2200 lb thing.)

[Bell_ringer]

And yet the green arc ends at 110kts IAS and the poh warns against anything above unless in smooth air..

[[email protected]]

Now you are just being silly. Why? Do you believe that doesn't happen?

[ApolloHeli]

Why? Do you believe that doesn't happen?

Trying to avoid getting roped into this debate, but I believe he's implying it's nicer to have an EFIS tell you how are you are from full throttle (and when you've reached it) so that by the time your Nr is drooping, you're aware of it and making control actions based on that information. I think if the only thing alerting you to the loss of Nr is the warning horn, you're probably stuffed by then. As many have said before, the MAP gauge is sufficient for defining limits, but I'll agree with 'a(whatever the username is)' in saying that the MLI of the Cabri makes it much clearer to the pilot what your limit is and how far from it you are. My 2 cents worth; having a 0-100% gauge on a Robbie might just help the not-so-stellar pilots among us to realise when they're testing the limits of the aircraft and encourage them to calm down - especially the casual pilots who don't necessarily do all the pre-flight planning we all take for granted.

That being said, this is all a massive thread drift from the OP (a fatal crash presumably caused by TR anomalies), so I hope the 'proving people right on the internet' debate can subside to keep this thread relevant.

P.s. The Cabri is better.

[Ascend Charlie]

Shirley somebody would be smart enough to modify the MAP gauge to have a temperature and a pressure altitude input, which moves the outer scale (0 - 100%) so that with altitude / temp increase, the 100% part of the scale moves anti-clockwise towards the needle.

And don't call me Shirley.

[havick]

Shirley somebody would be smart enough to modify the MAP gauge to have a temperature and a pressure altitude input, which moves the outer scale (0 - 100%) so that with altitude / temp increase, the 100% part of the scale moves anti-clockwise towards the needle.

And don't call me Shirley.

Sadly that would require technology available to us decades old to be put into production.

[[email protected]]

ApolloHeli - I remember an important part of my R22 conversion was demonstrating the ability to recognise and recover from overpitching (ie rasing the lever past the point of max fuel available). You can't miss the sound of the Nr decaying even before the unfeasibly loud horn goes off.

This should be a basic skill for a SE piston heli pilot.

[Twist & Shout]

I could add to the thread drift, or simply point out that lack of power, or the finer points of where the “flight manual limit” was on the day in question, almost certainly did not contribute to the crash in question.

Pax on a mtce test flight would seem to have contributed to the fatalities and serious injuries.
The failure seems to be atypical and as yet unexplained.

[capngrog]

I could add to the thread drift, or simply point out that lack of power, or the finer points of where the “flight manual limit” was on the day in question, almost certainly did not contribute to the crash in question.

Pax on a mtce test flight would seem to have contributed to the fatalities and serious injuries.
The failure seems to be atypical and as yet unexplained.

Thank you.

Cheers,
Grog

[Winfield83]

I have been following this thread and other's for some time now. and I, like other's here are interested to see the final ATSB report into what happened in flight.

Let me 1st introduce myself as an A.M.E
Several members here have already mentioned drive shaft damper bearing failure, flex plates cracked RB's etc etc. I am not an accident investigator by any means, however after several R22 and R44 rebuilds and 100 hourly inspections on R22 and R44's being operated in desert country (red dirt, mustering environments) I have come across many times over the years that there has been excessive wear associated with the C121-17 push pull tube connecting to the A120-3 Bellcrank Assembly on the TRGB, has excessive wear from dirt build up between the C121-17 Push pull tube and nylon guides within the tail cone.

The aircraft in question was only operated out of the industrial estate where the incident occurred. Never from bitumen or asphalt helipad as per the ATSB investigation. The aircraft would have spent it's life cycle ingesting dust and dirt each time it left or returned to it's home base. No doubt dust and debris was ingested into the tail cone and associated empennage for some time and probably since aircraft in question was sold in this country. I have seen wear on the C121-17 on many R22 and R44's which are based on the many cattle properties through out this country where the dirt build up between the nylon bushes has worn deep into the push pull rod and required replacement or renewed paint to be applied to effected areas.

To me, it looks as though the push pull tube has worn through which would not have been detected with a ground run and TR balance. The push pull tube has given way causing the TR to swing at an angle which resulted in complete loss of control and the TR blade to cut through the tail cone assembly resulting in the fatal incident currently under investigation.

Anyone who works on R22's or R44's which spend their lives mustering or in dirt\dust would have encounted the wear produced on the C121-17 tube from dirt build up between the nylon bushing.

IN MOST CASES I HAVE EXPERIENCED, THE PUSH PULL TUBE HAS NEEDED TO BE REMOVED TO FULLY INSPECT FOR WEAR BETWEEN THE NYLON BUSHINGS.

My reference book is the R44 IPC found here: R44 IPC - Robinson site *unable to post links until I have reached 10 posts"
65.0 - Item 8
C041-1 Damper Assembly

65.6 - Number 19
C121-17

67.90
C121-17 Push pull tube.

Anyone else able to shed some light on their experiences when removing the C121-17 on mustering choppers?

Cheers

Winfield.

[aa777888]

Excellent post Winfield83, thank you!

[gulliBell]

Excellent observation, but remind me, wasn't this an almost brand new helicopter with a couple of hundred hours total time? In which case most unlikely anything on it was worn out.

[Arnie Madsen]

This was a fairly new machine with less than 300 hours
I am sure the factory would have assembled it properly

If it turns out some component in the TR drive was not assembled properly
or tightened properly it most likely happened during disassembly & reassembly
when it was shipped overseas.
That is my guess anyway.

[bellfest]

The tubes and sometimes bush asembly can wear quite a bit and should be inspected closely during routine maintenance, particularly when operating in dusty environments. Add in to that some young hopper (or old...... some just never grow out of it) going from one control stop to the next in their own dust and using a multitude more inputs than necassary, than an already prone bearing surface will have an even rougher ride.
I would think though, that excessive wear to the point a failure of a tube or guide would occur, would more likely lead to jammed pedals rather than a complete control failure/disconnect. Very unlikely also in such a low houred aircraft.
Also, a complete control disconnect should have no affect on the teetering of the tail rotor and should not lead to a blade striking the tail. Definitely lead to a few other problems but I wouldn't think that would be one of them.
Anyway, I'm teetering on the edge of speculation and that's something I try not to do before the ATSB has done their thing. A sad tragedy whatever the cause.

[TWT]

https://www.atsb.gov.au/publications/investigation_reports/2020/aair/ao-2020-033

[Cloudee]

Have a look at the standard of aircraft operation in the Wild North West of Western Australia.

Contributing factors

Following a period of pedal vibration over at least 2 flights, overstress fracture of the attachment lugs of the tail rotor gearbox input cartridge occurred. The source of the loading that led to the overstress fracture was not conclusively determined.
Two pilots experienced vibration through the helicopter’s tail rotor pedals on separate flights and did not endorse the problem on VH-NBY’s maintenance release. Additionally, following tail rotor inspection and vibration analysis on the ground, the engineers did not endorse the requirement for a maintenance check flight on the maintenance release. As a result, the value of the maintenance release as a tool for communication and management of airworthiness was lost.
A recommendation in the R44 pilot's operating handbook was not followed. It advised pilots that following detection and inspection of an unusual vibration, they should hover the helicopter then have it reinspected before resuming free flight.
The pilot conducted a towering high-power take-off in VH-NBY from a confined area with 3 passengers on board. The unnecessary carriage of passengers resulted in a significantly more severe outcome following the inflight breakup.
Shortly after take-off, following the overstress fracture of the attachment lugs, the tail rotor gearbox separated from the helicopter. This led to fracture of the aft tail cone bulkhead and separation of all components attached to it, including the horizontal and vertical stabilisers.
With limited time and the stress associated with the emergency event, the pilot did not apply the pilot’s operating handbook procedure for responding to a tail rotor emergency. Prompt application of the procedure would have reduced the likelihood of loss of control, and therefore improved the potential for survivability.

Other factors that increased risk

The pilot did not have a valid flight review for the R44 helicopter type or a current medical certificate. The former increased the risk of an inappropriate response to the tail rotor emergency and the pilot was not legally authorised to operate an R44 helicopter at the time of the accident.
The owner of VH-NBY demonstrated acts of non-compliance with multiple aviation safety regulations. Additionally, VH-NBY was operated in a manner that increased the risk of damage or stress to the helicopter on multiple occasions. These actions had an adverse influence on safety and imposed unnecessary risk on passengers and third parties.
Although the registered operator of VH-NBY was responsible for the continued airworthiness of its helicopter fleet, they did not employ a conservative defect resolution process that would have supported further trouble shooting.

Other findings

The attending engineers found that visual inspection of the tail rotor system and associated components, running the helicopter on the ground, and dynamic tail rotor balancing, could not replicate the stated problem. It is likely that the vibration only presented in powered flight.
There was a history of unreported accidents and incidents with the registered operator of VH‑NBY's aircraft, in both commercial and private operations. These occurrences included 2 tail rotor strikes in different R44 helicopters, and a total hull loss of another R44 helicopter (VH‑ZGY) that resulted in serious injuries to a passenger.
Although a fuel bladder was punctured during the accident sequence, and fuel was lost from the tanks, the fuel bladders reduced the flow rate of escaping fuel, which reduced the risk of a post-crash fire.

[Twist & Shout]

So just a freak accident, that no-one could have anticipated! :ugh:



Obviously surveillance must be improved, with more of these types of operators removed from the airspace ASAP.

Before innocent casualties become involved as they were in this case. Very sad.

The trust betrayal of the passengers and the young girls parents is disturbing, and potentially speaks volumes regarding the pilots personality.

[FH1100 Pilot]

I got to thinking...

1) Low-time machine and the tail rotor comes off? ATSB cannot find a definitive cause?

2) You know how we always caution pilots to operate the helicopter within limits so something doesn't break on the next pilot? Maybe this guy was a victim of...well..himself. Maybe he was his own "next pilot." The ATSB cast aspersions on him, noting all the other incidents and accidents his helicopters have been involved in. Add to that the fact that he was technically not legal to fly, which demonstrates a certain casualness with rule-following. We might infer that this casualness carried over into how he operated the ship. Perhaps he was not diligent about observing power limits while at the same time being more rough on the pedals than is necessary? We don't know what he did with that R-44 in the 280 hours he flew it, but I'll bet it was used and abused. Maybe this guy did it to himself? Maybe he was used to horsing those things around? His history certainly hints at this.

3) Here's one amazing tidbit from the investigation: While there was a large shift forward in centre of gravity it is highly likely that VH‑NBY’s centre of gravity remained within limits following the in-flight break-up. Are you kidding me?? This implies rather strongly that the ship could have remained controllable and *perhaps* landed safely after the "event" (as has evidently happened before). How many other helicopters can do that? The ATSB does go on to say that once the rotation began, proper control inputs (e.g. closing the throttle and getting rid of the torque) would've had to have been done within one rotation as the lateral g-forces become too high to manipulate the controls. As someone who had an actual t/r d/s failure in a 206 in a hover which went 'round a couple of times, I can attest that the lateral forces quickly become high and disorienting. And remember, the 206 has the mast above the back seat, not behind the cab like the R-44. So the 206 pilot is closer to the center of rotation, in other words.

I've never been an outright Robbie-hater, and my respect for the R-44 has grown with this accident.

[[email protected]]

I've been an R22 hater but have no gripe with the R44 apart from that rotor design.