EC225 crash near Bergen, Norway April 2016 [Archive] - Page 4

Kawijet

17th May 2016, 17:34

After reading the initial report, the picture of the Suspension Bars look suspicious to me.
Someone has already stated this on here already but it is very interesting - something does not seem to add up.

The photograph of the detached rotorhead lying on the hillside with the suspension bar sticking up, shows NO bracket. We can then assume the bracket is still connected to the fuselage. However, in the report photographs, it shows the Suspension Bars, brackets and all pins in good condition. Now that is impossible! In order for the suspension bar to become seperated from the bracket (as we see in the rotor head picture as it was found) then either the bracket eye has broken releasing the bar, the pin has sheared releasing the bar or the bar ends have broken. NONE of these things have happened!? So how did it seperate if all components are present and correct?? And its unlikely the accident investigators removed them as some have previously suggested, as the other bar is still complete. Also the final photo of the report shows the suspended rotor head with bars attached - surely they would have re-instated the bracket for that photo if they had previously removed it?
The only explanation is it has been incorrectly assembled, but even then if the pin did fall out, what are the chances of finding both the pin AND nappy pin in the wreckage? Either that or that is not the pin, nappy pin or bracket.....

Something doesn't add up here.

Colibri49

17th May 2016, 18:34

industry insider

Your response "You can ask as many times as you like but I don't think you are going to find that answer on here anytime soon, probably until the report is issued." is undeniable and my question has always been largely rhetorical, because short of someone close to the investigation giving out this kind of information, I never really expected a direct answer.

However if that Norwegian EC225 gearbox had been making even the slightest metal particles from the epicyclics or mast area, then it must be in the engineering records. With the tragedy of REDL fresh in people's minds, there's no way that the aircraft would have been allowed to continue operating and Airbus Helicopters would very likely be insisting that all EC225 and Mk2 types remain grounded. They're not, at least that's not how their announcements seem to me.

While I wouldn't want to see any rush to get Super Puma types back into service before as much certainty as possible has been reached, "letmein" has a point in his submission above.

AW009

17th May 2016, 19:04

@Colibri 49: Chapeau!

n305fa

17th May 2016, 19:39

n305fa

According to what I've researched on Google, there is a dedicated "epicyclic module chip detector" which you describe above as "not very efficient, small size, big epicyclic case radius" which is generally correct. What I myself saw when the conical housing and top of the gearbox got dismantled to remove the ring of magnets, was a lip right around the edge of the tray to which the magnets were attached.

There was a gap of 1 or 2 cm in this lip to allow oil draining down from the epicyclics to get "focused" into a narrow stream passing over the epi chip detector below the gap (engineers please correct me if I'm wrong), thereby increasing the chances of metal particles getting detected.

So if that lip with a gap is still part of the tray's design and now that the ring of magnets is no longer in place, even the slightest particle from the epicyclics and mast area would be detected at a very early stage and long before the risk of a catastrophic break-up might occur. I can't accept the idea of only one or two particles being detected by this improved system (without magnets) followed by a sudden break-up?

Hence my question for the 3rd time "Was there any history of the Norwegian EC225 gearbox making metal before the crash, because if not the likelihood of similarity with REDL is probably reduced?"

Colibri

Having seen a number of "open" 332 &225 gearboxes in my time I can say there is no channelling of oil to the epi chip detector. There is a ridge around the edge of the outer module separator plate with a small depression in it where the epi chip detector sits. It's shown in fig 11 of the REDL report. As described to me on a course at EC/AH the Epicyclic chip detector relies chips being flung into its influence by the epicyclic system and by oil draining past the detector not by oil channelling.

Since REDL the procedures for assessing any particles found in the MGB has changed significantly.

EC 155

17th May 2016, 19:46

Excuse my French, but why is it that EASA are approving helicopters to fly and the local authorities grounds them.....I would have thought and hoped that it was EASA as the regular authority who either approves or denies aircrafts to fly, isn't it the beauty of EASA/EU???

Pablo332

17th May 2016, 20:02

n305fa

17th May 2016, 20:34

How long can a presumed criminal be held in custody without charges? So far, the AIBN hasn't come up with any evidence, none, zilch, that this accident was caused by a manufacturing or design flaw of the transmission. Airbus Helicopters clearly thinks that the transmission wasn't to blame here.

It may be best, at his point, to remove all restrictions, due to lack of evidence, and let industry decide if they want to operate the 225.

Lack of evidence does not mean something didn't happen.

Let's not forget the investigation is still in its early stages with a search for significant items still ongoing. It's easy for us to sit at our computers hypothesising but the investigation can only publish factual information and their analysis of those facts. I assume that if there were facts relating to the airworthiness of the 225/332 the AIBN , Norwegian CAA,UK CAA and EASA would issue something.

However frustrating it is, we have no option but to wait for the investigation to turn up something to either eliminate potential causes or focus the investigation on a particular issue. I've no doubt that there is significant pressure on the investigation team to find the cause or causes of this tragic event.

handysnaks

17th May 2016, 21:03

They also haven't come up with any evidence that it wasn't the gearbox that failed. However, a sobering picture of a full set of rotorblades 'gently' lowering themselves onto terra firma sans helicopter is evidence that something wasn't quite right!

Kawijet

17th May 2016, 21:05

After reading the initial report, the picture of the Suspension Bars look suspicious to me.
Someone has already stated this on here already but it is very interesting - something does not seem to add up.
The photograph of the detached rotorhead lying on the hillside with the suspension bar sticking up, shows NO bracket. We can then assume the bracket is still connected to the fuselage. However, in the report photographs, it shows the Suspension Bars, brackets and all pins in good condition. Now that is impossible! In order for the suspension bar to become seperated from the bracket (as we see in the rotor head picture as it was found) then either the bracket eye has broken releasing the bar, the pin has sheared releasing the bar or the bar ends have broken. NONE of these things have happened!? So how did it seperate if all components are present and correct?? And its unlikely the accident investigators removed them as some have previously suggested, as the other bar is still complete. Also the final photo of the report shows the suspended rotor head with bars attached - surely they would have re-instated the bracket for that photo if they had previously removed it? The only explanation is it has been incorrectly assembled, but even then if the pin did fall out, what are the chances of finding both the pin AND nappy pin in the wreckage? Either that or that is not the pin, nappy pin or bracket.....

Something doesn't add up here.

henra

17th May 2016, 21:32

Kawijet

17th May 2016, 21:33

http://s32.postimg.org/542xaf9ed/chopper_rotahead.jpg

industry insider

17th May 2016, 21:50

Colibri

my question has always been largely rhetorical, because short of someone close to the investigation giving out this kind of information, I never really expected a direct answer.

It's a question that many of us have been asking since the accident.

The 225 in my world is only grounded by our helicopter operator. It's not grounded by EASA, Airbus or the regulator. It's also grounded by me, as the advisor who advises the company.

The grounding is causing us pain. Even after 20 days, there are massively divergent views. Some ask "why can't we fly it?" Some people never want to fly in it again and some crew never want to fly it again.

I suppose that there is still too much emotion and to few facts to make a balanced decision, so we maintain the status quo until the facts emerge.

Offshore pilot

17th May 2016, 22:21

Colibri

Agree.

The condition of Suspesion bar eye, bolt with pin in adidtion to the condition of bracket are main questions. Hopefully this will be clarified soon to indicate internal MGB failure or departure of the suspentson bar.

helonorth

17th May 2016, 23:41

Advisors advise. Management make decisions.

birmingham

18th May 2016, 00:04

Guys this gearbox has form.

It is entirely natural that the world wants to be reassured that the gearbox is not to blame. The AIBN are consumate professionals as are HS. The AIBN would not ground the aircraft unless they felt it was entirely necessary and HS would own up if they had discovered a blatant maintenance error.

The AIBN will have seen the barbecue plate, which will tell them much, they are wholly familiar with the circumstances of previous incidents. They will know if this machine had bee making metal.

If this was an obvious maintenance error with the suspension/lift bars they would have said so by now and lifted the ban.

Nobody wants to see comapnies ruined and hard working professionals destroyed, times are tough enough in the NS. So we need to trust these guys to do thier jobs. they are honest people and if they say no definititve conclusions can be drawn yet I am inclined to believe them.

I agree that the head needs to rule the heart, i first flew on a Puma in 1975 at Odiham and would be happy to do so again. I have a soft spot for this machine but recognise many do not. I'm not the customer or much more importantly his workforce.

The AIBN know that unless their report exonerates the gearbox the Pumas are utterly finished in the NS and the collateral damage will be enormous.

So they need to present an authoritative fact based presentation.

I'm afraid anyone wh thinks the Super Puma can survive another catastrophic gearbox fatality is in cloud cuckoo land.

letmein

18th May 2016, 00:18

birmingham

18th May 2016, 00:31

Agreed.

This information is vital and will have to enter the public domain.

The delay is unfortunate as if there is a specific, entirely unrelated cause to previous incidents it is important it is made public asap. Every day that goes by will harm the prospects of the aircraft and operators

letmein

18th May 2016, 00:58

Birmingham
I'm afraid anyone wh thinks the Super Puma can survive another catastrophic gearbox fatality is in cloud cuckoo land.

At the end of the day, the Super Puma series may have just run out of lives.

Even the 225 and L2 CFIT ditchings count.

Being pragmatic about the latest incident may not really matter anymore....can't erase that picture of the rotor flying off.

My last post on this.

Nadar

18th May 2016, 01:43

And its unlikely the accident investigators removed them as some have previously suggested, as the other bar is still complete.
..
but even then if the pin did fall out, what are the chances of finding both the pin AND nappy pin in the wreckage? Either that or that is not the pin, nappy pin or bracket.....

Something doesn't add up here.

As I see it the only possible explanation is that the investigators removed them. As you're stating, if they weren't removed they would have been deformed/broken in som way unless they were never installed. I don't think that the bracket is connected on one bar "proves" that the other one wasn't complete, they clearly must have removed either the lower or the upper end (or both) on the suspension bar that is unconnected in both ends. As I see it it's clear that they have removed the pins on some of the four suspension ends in question, so I don't understand why they wouldn't have removed them on all the 3 unconnected ends. I think it's more likely that there's an issue with the one that's still connected, that it is bent or distorted in a way that makes removal impossible without force.

As for the front suspension bar we really have no other information than that the top mounting broke. I think it's very unlikely that it has broken more than one place, and the front suspension bar has probably stayed attached to the airframe. I'm guessing they only showed the part of the front suspension bar that "is of any interest" - where it has given way.

Either way, it's important to remember that in what state these were found is only a mystery to us. The AIBN knows if they were found mounted or not, which makes me believe that it can't be a "simple explanation" like missing nappy pins. If that were the case, AIBN wouldn't be in any doubt if the accident was due to the some kind of suspension bar failure or rotational lock up. For this to be an "open case" things must seemingly have been correcly put together and the question is if some kind of fatigue/crack or otherwise non-obvious problem with the suspension failed and caused the damage to the gears as the break up was happening, or if something locked up and the momentum in the rotor broke the suspension.

Given that the rotor seemed to still rotate at a high speed in the video and that the damage to the blades are relatively modest, I'd say that the most likely scenario is that something locked up. If the suspension failed causing the rotor to hit the tail or some similar scenario, I'd think that the blades would either be "shaved off" and/or the rotor would have lost a lot of momentum. I don't know enough about the strength in the blades, their attachement or the material in the tail to speculate how that would play out, but a considerable amont of "braking" would have had to happen to break the planet gear. I think this force would have been visible on the rotor and blades.

OnePerRev

18th May 2016, 01:45

Airbus Helicopter Technical exec Dumont addressed AHS today, appropriately brief speech and with condolences and respect. Only meaningful comment was that they deliver a machine 10 years ago, it crashes, and they have no history of anything it did in between.

Other industry execs chimed in that manufacturers need a committed customer as a willing partner in order to get "Big Data".

TylerMonkey

18th May 2016, 03:14

It now is obvious that the lower strut bracket was removed by them where the rotor landed. Somewhere under the rotor was the second strut with the thin silver metal band around it.
They have not disturbed that in all the photos, left it attached to its lower bracket .
The brackets and pins are very important evidence, who knows how long the rotor was going to lay there until it was moved. With the bracket sticking up in the air and easy to remove by sliding one pin, maybe they filmed it in detail then decided it was safer to have it in a ziplock bag and labeled and under their control. Not waiting for someone to wander by and possibly disturb it. Makes perfect sense to me now after seeing all the 5 pins. No other explanation covers the facts.

AW009

18th May 2016, 05:18

The biggest danger would be if the facts remain on the seabed, because then the decisions will become irrational. Thus, the bandwidth would be that an insinuated 2nd case ‘G – REDL’ the SUPER PUMA will not survive and to wait for a 3rd case is absolutely prohibited!Inevitably the success story of Super Puma was canceled by the offshore crash series within the last years to a discontinued model and the resulting lean spell is for the account and risk of Airbus Helicopters.

In 1974, Aérospatiale commenced the development of the new medium transport helicopter SUPER PUMA AS332 based on its SA 330 Puma going back to 1965 and the project was publicly announced at the 1975 Paris Air Show.

40 years later at the 2015 Paris Airshow, Airbus announced the launch of a development program to build the X6 helicopter that would replace the Super Puma in 2022 - 2023 and will have a military variant delivered in 2030. Compared to AgustaWestland and Sikorsky, Airbus has slept through a whole generation of helicopters, which already flies in civil and military markets.

n305fa

18th May 2016, 05:19

Airbus Helicopters has, almost since day one, pointed their finger directly at a suspension bar mounting issue. All restrictions were lifted 48 hrs after incident. EASB 53A058 (3 May 2016) directives are focused on mounting issues only. Fact is, Airbus Helicopters is the expert and authority on the ec225 (and 332/L2).

Pressure must be mounting for the AIBN to provide some evidence to support their implied thesis, that accident's root cause is somehow related to manufacturing or design. No evidence provided thus far. Not even a teaser. Again - none.

It is also odd that the AIBN seems to be dancing around the suspension bar problematics:

The problem is, if the investigation

- Where is the front suspension bar, is it missing?
- Where is the lower front mounting bolt and safety pins, are they missing?
- What is the state of the lower front mounting bracket? undamaged, damaged, missing?
- Is damage of the suspension bars and brackets consistent with REDL? or is there a clear difference?

The AIBN don't ground aircraft, that rests with regulators, Norwegian CAA, UK CAA, EASA etc. National authorities within EASA can, if the feel the action is justified, ground an aircraft type regardless of what EASA decides.

I would suggest that the grounding orders are in place as a result of what is know about the accident, rotor seperation etc and previous events on the 225 and 332L2. regardless of AH's product knowledge they can only advise the investigators and regulators. AH can say what they want but at the end of the day they have to convince the regulators that there is a good enough case to "un-ground" the fleet

Kawijet

18th May 2016, 07:58

I agree with what you guys say - It MUST have been removed by the investigators but if so why? If the bracket was there and had all the components then why would they feel the need to remove it? The proof that it was still attached before the crash would be there so removing it would be pointless. I hope you are right and they photographed it in place and the removal of it.

It just seems strange that AH are keen to say it is not a mechanical at this early stage - that is a crazy thing for them to do, reputation wise, if it turns out to be a mechanical fault!

Another interesting point - the engine intake screen was found far from the main wreckage before the crash site ("Air inlet screen" - accident report map),. Could it be possible that, if one of the rear struts did infact detach, the rotorhead pitched forward and the blades struck the nose and front engine cowlings/intake screens before becoming fully detached?

Please note I am just venting my thoughts on here and speculating, not directly asking for answers.
I know the investigation is on going and will take some time to complete.

aheoe26104

18th May 2016, 09:55

This from the "AIRCRAFT ACCIDENT REPORT 2/2011" for the "Report on the accident to
Aerospatiale (Eurocopter) AS332 L2 Super Puma, registration G-REDL 11 nm NE of Peterhead, Scotland on 1 April 2009"
1.12.3.4 Main Rotor Gearbox main module
The gearbox, (serial number M2092) had remained attached to the airframe by the flexible mounting plate, which is designed to react the gearbox torque. The mounting plate had sustained little damage in the accident. This observation was pertinent in that it helped to exclude the possibility of a lift strut failure as being a primary cause of the accident, since such an event would transfer lift loads, via the gearbox, into the mounting plate causing obvious distortion.

Someone mentioned that the same applies to this accident, the BBQ plate does not show evidence of stress that supports the suspension bar failure theory. Can this be confirmed? Does not look so from the photo below.

http://images41.fotki.com/v1634/photos/4/3710704/13970695/gearbox-vi.jpg

cteneto139

18th May 2016, 11:29

by the way, any "rotor detachment" is absolutely unacceptable!

cteneto139

18th May 2016, 11:39

I´ve been flying Puma family since my first job as a pilot (SA330J, A332L2 and EC225).
I´d like to stay flying them... They are good machines, but I have to say that, whatever the main reason have been, it is unacceptable a rotor separation in flight!
Just to remember Boeing 234 and WG30!!! I think Airbus must have good answers to the industry asap!!!

Nadar

18th May 2016, 12:13

Someone mentioned that the same applies to this accident, the BBQ plate does not show evidence of stress that supports the suspension bar failure theory. Can this be confirmed?

It's hard to be sure about anything as long as the picture quality is this limited. I'm not familiar with how the BBQ plate usually look or how it would deform if it was exposed to massive vertical loads, but from my layman's point of view it doesn't seem to have been exposed to great vertical forces.

birmingham

18th May 2016, 12:32

cteneto139 you are quite right ... and your opinion is based on a much deeper knowledge of the machine and the risks than most AH customers.

I think the regulators may have done AH a favour here. A business as usual until we understand the problem worked out ok the first time we has a catastrophic failure. it would also have worked if the last incident was in the distant past. It will still work away from the NS where customers were not so directly affected by previous incidents. But in the NS customers and trade unions would have been in an impossible position. Rightly or wrongly a substantial number of them had formed the opinion it was a dangerous type - a view that could only be dispelled by a decent interval of accident free flying. AH can tell that constituency the thing is safe, problem is many are no longer listening.

AH are in a terrible position; If they genuinely believe that the accident was caused by other factors than the gearbox (and surely they must) then all they can really say is that there is no reason to stop flying it. They can't give vent to their full suspicions for a whole variety of reasons many of them to do with liability. If they don't have private evidence to support this (surely they must)they are heading for a Gerald Ratner moment.

and what about the report it can have four very general conclusions these being;

A. It was a repeat of REDL - everybody hopes not, Airbus clearly believes that wont happen - result catastrophic for Pumas everywhere
B. It was caused by some other form of deign or manufacturing failure result almost as bad as A above
C. It was caused solely by a maintenance error. Result people will want to know how such a thing could have happened in the NS and why it would not happen again.
D. No conclusive reason could be given (see A above)

None of the above scenarios make for good reading. At least if the AIBN can ultimately make an evidenced based conclusion as to the cause AH and its operators can start to move forward.

There is a new model scheduled for 2022 - not far ahead.

I wonder how many Pumas will be flying in the North Sea when it shows up?

aheoe26104

18th May 2016, 12:40

In REDL's accident report you will also find reference to this:

1.18.4 Accident to Aerospatiale SA330J, 9M-SSC, 16 December1980
On 16 December 1980, an Aerospatiale SA330J Puma helicopter, 9M-SSC, crashed in a swamp forest near Kuala Belait in the State of Brunei. The crew of two and all 10 passengers were fatally injured in the accident, which resulted from an MGB failure similar to that which occurred on G‑REDL. The MGB of the SA330J is fundamentally similar in layout to those of the AS332 series of helicopters, although the components are not interchangeable and the gear material specifications are different. The gearbox in the 9M-SSC accident had a recent history of quantities of metallic debris being found on the magnetic chip detector in the main module. The epicyclic module was not equipped with a detector.
The synopsis of the report on this accident contained the following:
‘The accident occurred following the loss of the main rotor assembly, together with the attached bell housing containing the second stage gears of the epicyclic gearbox. Almost simultaneously, the entire tail boom section parted from the aircraft.
It is concluded that the most likely cause of the accident was a planetary gear failure in the second stage of the two stage epicyclic main gearbox reduction gear; the associated metal debris caused jamming within the rotating assemblies, generating forces which fractured the common epicyclic ring gear and the main gearbox casing. This resulted in the gross instability in the rotor system, which caused blades to strike the fuselage.
The initial cause of the accident was due to the mistaken health monitoring of the gearbox, leading to a deterioration of the mechanical condition of the gearbox components.’
The first of two causes stated in the report was as follows:
‘The accident was caused by the disintegration of a secondary stage planet pinion [gear] within the gearbox following a seizure of its associated roller bearing.’
The break-up of the second stage planet gear in this accident was precipitated by a maintenance error which allowed a severely deteriorated gear to fail. No part of the failed gear was recovered and the entire first planetary stage was missing. However, the break-up of the gear resulted in circumferential failures of the ring gear casing, above and below the epicyclic stages, together with a vertical rupture.

Apate

18th May 2016, 13:50

aheoe26104

18th May 2016, 14:10

If anyone has access to the original accident report for 9M-SSC, they will see an Addendum containing a statement from Eurocopter that they did not agree with the root cause finding of the report. Some things never change!
Yep, they did it then and looking at the recommendations in REDL's report, you have to ask whether they complied/accepted fully then too. (See recommendations below first quote)

In Appendix 1 to the report, the manufacturer (at that time Aerospatiale) made various comments, some of which are included below:
‘….the assumption of the box bursting as the accident first cause is negated by the following.
-- No fragments of the missing second stage [planet gear] have been found
-- Relatively correct condition of high speed stages, which should have shown epicyclic gear jamming marks (especially on flexible couplings and torquemeter shafts)’
-- When a planet gear rupture generated by its race chippings occurs, it is necessarily preceded by the initiation of fatigue cracks through the rim

4 Safety Recommendations
4.6 Safety Recommendation 2009-075: It is recommended that the European Aviation Safety Agency, in conjunction with Eurocopter, urgently review the design, operational life and inspection processes of the planet gears used in the epicyclic module of the Main Rotor Gearbox installed in AS332 L2 and EC225LP helicopters, with the intention of minimising the potential of any cracks progressing to failure during the service life of the gears.
4.11 Safety Recommendation 2011-036: It is recommended that the European Aviation Safety Agency (EASA) re-evaluate the continued airworthiness of the main rotor gearbox fitted to the AS332 L2 and EC225 helicopters to ensure that it satisfies the requirements of Certification Specification (CS) 29.571 and EASA Notice of Proposed Amendment 2010-06.
4.14 Safety Recommendation 2011-043: It is recommended that Eurocopter introduce a means of warning the flight crew, of the AS332 L2 helicopter, in the event of an epicyclic magnetic chip detector activation.

Skotty

18th May 2016, 14:31

aheoe26104 @ #784

The barbeque plate is attached to the fuselage structure at its forward right corner and its rear left corner. Looking at the photo its points of attachment at the front are to the piece of fuselage (yellowish) which is shown to be bent upwards, so it has been distorted to some extent as far as I can tell. Whether this has happened at the start of the tragic event or on impact with the ground who can say?

Unfortunately we can't see the area of rear attachment.

cteneto139

18th May 2016, 14:52

I remember in 1997, when a SA330J had a sudden stop after a freewheel #2 had a sort of slippage during the starting procedures... Because the SA330J has not tripletach, the captain was unable to notice that the second engine had not engaged... of course, the Eurocopter + operator, have pointed the fault to the captain for that... you can imagine, the helicopter has no advisory or instrument about the N2(Nf or Ntl) and the fault was from captain!!!

212man

18th May 2016, 15:57

Lonewolf_50

18th May 2016, 16:00

Pittsextra

18th May 2016, 16:04

AH are in a terrible position; If they genuinely believe that the accident was caused by other factors than the gearbox (and surely they must) then all they can really say is that there is no reason to stop flying it. They can't give vent to their full suspicions for a whole variety of reasons many of them to do with liability. If they don't have private evidence to support this (surely they must)they are heading for a Gerald Ratner moment.

Ref: this ^^

What couldn't they say and more to the point why wouldn't they say?

birmingham

18th May 2016, 16:13

Pittsextra

Because they are the manufacturer and a party to all this. There will certainly be liability claims. They will be legally constrained as to what they can say at this stage. They will subsequently provide evidence to the enquiry and anything they say at this stage would prejudice this. They continue to stand by their product and hope the investigation and subsequent enquiry will exonerate them.

Pittsextra

18th May 2016, 18:56

B'ham - when I read (for example) this:-

Airbus said it saw no need to suspend flights with the helicopter model, adding that its experts have conducted on- site inspections of the crashed helicopter parts, leading them to conclude there was no safety-of-flight risk for the fleet.

Read more: Bristow Grounds Airbus EC225 Helicopters After Norway Crash - NASDAQ.com (http://www.nasdaq.com/article/bristow-grounds-airbus-ec225-helicopters-after-norway-crash-20160502-00785#ixzz492Dh0CGN)

That doesn't sound very "legally constrained" and to not give further rational for the comment just seems very odd, especially since it isn't helpful to the aviation industry because at the very least it seems to have a major manufacturer concluding at this stage something very different to the regulator of two countries. It also suggests that they are able to conclude something that the accident investigators are not, which again seems odd.

Further (whilst not important in the context of the accident) given Airbus and Bristow are all tradable entities and this information is very much "market sensitive" one now wonders how they plan to manage the release to the market.

Lonewolf_50

18th May 2016, 20:45

That doesn't sound very "legally constrained" and to not give further rational for the comment just seems very odd,

It also suggests that they are able to conclude something that the accident investigators are not, which again seems odd. Consider a different angle on this: they are confident they have found something that the investigators will in due course also find and then report upon. They are choosing not to say much more for a good reason, cited above: to avoid conflicts with the investigating team's timeline and desire for thoroughness and caution. (This idea paints AB helicopters as a team player. No, I have no vested interest in ABH nor AB at all).

Pittsextra

18th May 2016, 21:35

It still makes no sense. You have to believe that AH executive have the best interests of their business at the forefront of any thinking - so to suggest there is no safety issue would be utter madness without any intelligent reason/rational. Otherwise EC225 crashes elsewhere in world in same circumstance as Norway and they are toast if that reason is a design flaw.

Likewise you have to believe that their engineering boffins are noble and stand up people so suggesting anything otherwise doesn't fit.

So if you believe all of that (and perhaps some don't) then not giving the back story to their findings is just dumb - in fact even more dumb is the inability for the other players in this not to be able to have eyes opened by any private conversations. Beyond which if it's so obvious that a multi billion dollar entity is prepared to bet the lot on a cause then why no news from "official" channels?

TylerMonkey

18th May 2016, 23:17

I have noticed in their photos one thing seems to be consistent. Any parts the investigation team disassembled to remove have remained disassembled in subsequent photos.
Other parts remain as they found them. The rotor head hung from slings shows this also, top pins are hanging loose by the struts and lower plates / pins are as they were on the table. One on, one off. The only exception is various nappy pins reinserted.
I think this supports the conclusion that one lower bracket was removed at the crash site.

cteneto139

18th May 2016, 23:35

Yes! There is only a Nr Tachometer on Instrument Panel! The engines have the standards instruments like Ng, T4 and Eng Oil Instruments.!

Satcomm

19th May 2016, 00:48

Cteneto139 - guessing that the captain must have been held at fault for a reason. Even without the triple tach, couldn't one pick up a slipping/disengaged input by the torque spilt between engines. I realize a tq spilt is not abnormal in a puma but they must have had some reason to state that the pilot should have noted it.

[email protected]

19th May 2016, 07:08

ISTR the Puma didn't have a torquemeter either, just a pitch gauge so the freewheel problem wouldn't have been apparent there either. Can't remember if it had fuel flow meters though.

Kawijet

19th May 2016, 08:28

Although this crash bears a significant resembelance to G-REDL, there is a big difference here (to me) in the failure mode. G-REDL report states that:

"The upper section of the gearbox
assembly, which included the remains of the second stage of the epicyclic
reduction gearbox, the conical housing and all three lift struts, had detached
from the MGB and were recovered with the rotor head."

So the second stage epicyclic gearbox AND conical housing had broken free and remained with the rotor head. This being consistent with the finding that the gearbox casing had been burst open, due to the broken planetary gear, and the casing fractured all the way around releasing the rotorhead. They also noted no distortion in the Barbecue plate to suggest suspension bar failure.

In this accident the conical housing does not appear to be connected to the lift bearing. Neither is the reduction gearbox section. We can clearly see the splined connection of the rotor mast suggesting it has slid out of engagement. (There is also a photograph of the rotorhead being airlifted away from the crash site to be examined and the conical housing is not visible here either - ill see if I can find it...).
The splined connection cannot simply "slide out" of engagement unless whatever is holding it in place is released (Suspension Bars/Conical housing to gearbox). IF this were another epicyclic destruction then we would surely see the same failure as in G-REDL, with half the planetary gears or at least the conical housing still attached as the failure of the gearcasing would be at the outer gear ring.
The Barbecue plate also seems very bent upwards on the front edge, which would be consistent with a rear suspension bar failure and rotor disc pitching forward - but could this damage have occured during the impact with land?
The amount of panels, cowlings and air intake screens scattered suggests to me the rotor struck the front of the aircraft rather than the tail boom during the break up.

With this in mind, it could be the reason that AH are so adament this is not a mechanical fault within the gearbox. And I would have to agree on that basis. An epicyclic failure would rupture the gearbox casing and, as in G-REDL, it would still be attached to the rotorhead. In this case the rotor mast has slid out of its splined engagement which suggests whatever holds it in place did not do so.... And if that pin was indeed missing from the suspension bar eye....

Only time will tell.

Kawijet

19th May 2016, 08:31

http://s32.postimg.org/sw5c0nw3p/DSC4941_1.jpg

Here is the picture of the rotorhead being airlifted from crash site - No conical housing?

Kawijet

19th May 2016, 08:44

Another interesting Photograph of Rotorhead and rear upper cowling with what looks like blade abrasions on the paintwork.

http://s32.postimg.org/e8ak77ozp/BA14573.jpg

ericferret

19th May 2016, 09:14

I would have thought that the NG guages would have given a clue. As pitch increaces the rotor RPM would droop leading to an increace in NG. However the freewheeling engine would not sense a droop and this would lead to an NG split.

AW009

19th May 2016, 09:31

@cteneto139 #802 & #793, @[email protected] #904: Might be in an older SA330 (J) produced 1968 – 1987, but this is not relevant to the crash of H225 LN-OJF. Definitely this old story does not apply to AS 332 L1, AS 332 L2 and EC 225 LP / H225, those are equipped with 1 & 2 triple tachometer and fuel flow meters.

birmingham

19th May 2016, 09:32

Kawijet you may well be correct here. Others have been questioning my post where I said Airbus must surely have more information than they have released to be sure of their comment that the aircraft is safe to fly. They obviously can't speculate as to the cause, but a safe to fly providing you check message must mean they are very confident not only that the failure occurred somewhere other than the second planetary stage, but that it was a failure somehow related to the missing lift bar. This would add even more weight as to why the AH statement is circumspect to the point of confusion. If they are pretty sure of the cause (and given what they have said I hope they are for their sake) they dare not be specific as the investigation will review the design, manufacture and maintenance of the components associated with this. It also helps understand why they have kept the ban in place. Although AH can express confidence in their product the AIBN must consider all the parties and if (and I stress if) it is a suspension bar issue they will have to try and conclude why the accident occurred and all the factors associated with it i.e.

1. Was maintenance correctly carried out (CHC)
2. Did it fail due to a manufacturing error (AH/Sub contractors)
3. Was the design in any way culpable (AH)

Also these things rarely will have a single cause.

They are going to have to make a big statement and some of the evidence hasn't even been recovered.

Whatever the report says It will specify the likely cause and make recommendations to prevent a recurrence. The worry for AH is that some of the customers are convinced (rationally or irrationally) that the best way to prevent a recurrence is to fly on other helicopters.

roundwego

19th May 2016, 10:30

The worry for AH is that some of the customers are convinced (rationally or irrationally) that the best way to prevent a recurrence is to fly on other helicopters.

So statistically, the next helicopter of this class to have a major accident will be the S92. Then what?

birmingham

19th May 2016, 11:40

roundwego statistically it is no more likely to be an S92 than a Puma or anything else.

However, i get your point.

If you just look at the facts;

1. Since that terrible month in 2009 when 33 oil workers died as a result of two separate MGB failures no oil worker has been killed as a result of an MGB failure on either type. (unless that turns out to be the case with the current incident).

2. One more oil worker has been killed in the oil industry on an S92 than a Puma as a result of MGB failure.

3. There have been three further serious NS incidents since 2009 all involving Pumas
+May 2012 G-REDW MGB & backup failed, ditched but no fatalities.
+August 2013 G-WNSB four dead but completely unrelated to MGB failure
+May 2016 LN-OJF 13 dead no evidence of MGB failure as primary cause so far.

So 50 dead in 7 years 5 accidents 1 S92 & 4 Pumas
33 died on Pumas 17 on S92

All 4 NS accidents involved Pumas.

Public perception in the NS though is 4 accidents in about 7 years 3 of them fatal and 33 dead. All Pumas.

It isn't rational or logical but people now have an unrealistic expectation of near total safety.

It is going to be extremely difficult to salvage the type's reputation.

roundwego

19th May 2016, 12:21

roundwego statistically it is no more likely to be an S92 than a Puma or anything else.

Of course it's more likely to be a S92 if 225s are grounded (commercially or by authorities). What other large helicopter will be supporting oil and gas?

Cows getting bigger

19th May 2016, 12:23

If it is the S92, I see Sumburgh getting somewhat busier.

birmingham

19th May 2016, 12:27

agreed - just meant that there are still other types in the NS albeit not 19 seat

birmingham

19th May 2016, 12:40

and also that Sikorsky would point out that the investigators in the S92 event in Newfoundland pointed to 15 other factors other than the MGB that were partial causes.

I think though it is also worth pointing out that these aircraft save more lives than they take!

birmingham

19th May 2016, 14:23

Mitchaa indeed I did - sorry about that. Do you mean 6 in total as S92 was Newfoundland or have I missed another

So by my reckoning in the NS it is 5 accidents in 7 years involving ditching or worse.
3 related to MGB 1 fatal two scary precautionary ditchings.
1 not connected to MGB though fatal
1 fatal yet to be resolved

33 fatalities in all.

Must be incredibly tough on all who put in so much effort to make this business safe

voando

19th May 2016, 15:39

Mitchaa - G-WNSB Loss of control not CFIT, surely?

Bishy

19th May 2016, 15:50

Birmingham,
Our passengers that we transport to the rigs are a suspicious bunch. Some were scared to fly in a red helicopter after the bond accident regardless of 92 or 225. There needs to be a lot more interaction between operators and passengers. I know that my company has gone some way to solve this. That said i was stuck offshore with a faulty sensor and was asked about the 225 gearbox modification. The poster explaining this was straight outside the guys office door and he had never looked at it. When i explained it to him he seemed a lot more comfortable being flown in a 225. Education is the key if the 225 will fly again. Lets wait and see what happens in the investigation.

Kawijet

19th May 2016, 16:08

Mitchaa,

Unfortunately you are not correct. The photo you post of G-REDL shows the conical and upper epicyclic still in position but its not too clear. What you saw in the wreckage was the outer ring not the planetary gear carrier. The report states these were all recovered together and that IS what it means - together meaning still assembled.
It makes sense - the gearcasing fractured at the point of the upper 2nd stage epicyclic module and thats where the gearbox parted with the MGB. Above this is the conical. So if the conical also parted the upper gear carrier would have fallen free of the rotorhead leaving the splined connector but that is not what you see in that photograph of the recovered rotorhead. It does not taper from the swashplate down to the splined rotor mast like in this instance, but looks the same width right down, due to the conical and upper module still in position.... Does that make sense?

The report is quite clear that these parts were recovered together assembled, which, is totally different from this accident.

helicrazi

19th May 2016, 17:08

Bishy,

There never were any red S-92's??? :ugh:

casper64

19th May 2016, 17:58

So... Lets ground all A320s, the egypt air aircraft made some unexplainable turns and 66 people most likely lost their lives (may they RIP). If no cause is found it will most likely mean the end of the A320. As the A319 and the neo versions are very similar in designs these types should be grounded as well until further notice...

Am I exagragating or are a lot of people on this forum doing just that with regard to the 225 crash? Let's just wait for the results. And if none found, the aircraft will most likely be released to service with some thorough inspections as we do with airliners as well... Or should we also ground the world wide fleet of Boeing 777 as we don't know the whereabouts of the Malaysian one and don't know why it crashed....

PlasticCabDriver

19th May 2016, 18:40

Bishy,

There never were any red S-92's???

Wish there were, those 92s would have looked awesome in Bond scarlet.

BASys

19th May 2016, 20:20

Hi Folks

Another interesting Photograph of Rotorhead and rear upper cowling
with what looks like blade abrasions on the paintwork.

http://s32.postimg.org/e8ak77ozp/BA14573.jpg
Kawijet -
Explain the relative positions of rotorhead and cowling
to achieve your "what looks like blade abrasions on the paintwork",
giving due account of the rotorhead's kinetic energy,
impacting the non-aerodynamic frangible cowling. ;)

Instead of your X-Files worthy supposition, ;)
try -
A non-airframe-specific component
previously painted in a different colour scheme.

ATB
Paul

AW009

19th May 2016, 20:49

To give the gist, I have just written in the German Defense-Political, Armaments and Procurements Blog "Augen geradeaus! (eyes straight!)" of Thomas Wiegold (Der Drehflügler, Mai 2016/II : Augen geradeaus (http://augengeradeaus.net/2016/05/der-drehfluegler-mai-2016ii/comment-page-1/#comment-236226)):

To adjust a preliminary interim status of AIRBUS H225 crash, please have a look on comment #805 in PPRuNe today (http://www.pprune.org/rotorheads/578298-ec225-crash-near-bergen-norway-41.html#post9380940):

The causes of accident, responsibilities and liabilities in my opinion might be supposed to develop even more intransparent and complex and we might return to #612 (http://www.pprune.org/rotorheads/578298-ec225-crash-near-bergen-norway-31.html#post9372108)

It also appears to me that "Discretion is the better part of valor, for the three (VIP- & governmental) Cougar AS 532 U2 of German MoD“ (in german language: „Vorsicht ist die Mutter der Porzellankiste“).

By this, the rather hollow and extremely glibly statement - being bare of any expertice and simply arrogant – of the German Air Force spokesman to the German Press Agency in Berlin on Saturday [30th of April, 2016, please check #644, http://www.pprune.org/rotorheads/578298-ec225-crash-near-bergen-norway-33.html#post9373218) is becoming more and more worst!

The user community of Augen geradeaus! (eyes straight!) is frankly spoken of an adequate and very professional level compared to PPRuNe and is due to a given expertice by a cross sectional area through the German Forces, FMOD and Industry (even commercial aviation) also very tolerant, open minded and responsive to any profound statement.

So please don’t hesitate with your comments, also in english language! Thanks ahead.

P.S.: Beside 35 years in comercial aviation I’m looking back on a military career of 12 years, retired as Captain and this is part of my motivation.

Skotty

20th May 2016, 00:45

Mitchaa @ #825

I agree with Kawijet @ #822

The following quote from the AAIB report on G-REDL confirms that the top part of the MGB detached along with MRH:

"The upper section of the gearbox assembly, which included the remains of the second stage of the epicyclic reduction gearbox, the conical housing and all three lift struts, had detached from the MGB and were recovered with the rotor head."

I have attached the drawing of the MRH (main rotor head) to which I have added pointers. LN-OJF's MRH separated at the joint between the lift housing and the flared housing. This is the same joint which would be separated when removing the MRH from the MGB (main gearbox) during maintenance. G-REDL's MRH separated at the epicyclic casing which is below the flared housing. This was due to the rupturing of the epicyclic casing.

We will just have to wait for the official report on why LN-OJF's MRH separated from the MGB at this point, but in my opinion this would be the most likely spot for the separation to occur if the lift forces were routed through the MGB casing instead of the struts. Of course this is just one out of many scenarios as to why it separated here.

AW009

20th May 2016, 04:53

@casper64: ’nomen est omen’ or ’ si tacuisses, philosophus mansisses’.

squib66

20th May 2016, 05:53

There is a better illustration of the structure here EC225 Main Rotor Head and Main Gear Box Design (http://aerossurance.com/news/ec225-main-rotor-mgb-design/)

The gears don't look like G-REDL, the separation is not the same as G-REDL, but the top of the front suspension bar has failed, whereas the rear two appear to have been pulled out at the bottom.

Skotty

20th May 2016, 08:11

Thankyou for the link squib66. The question is, did the front suspension top end fail as part of the initial incident or was it still attached and subsequently failed when the MRH hit the ground? If it was the former, what caused it to become separated from the main wreckage? And if it was the latter, where is the bar now? (I presume they would have included it in their pictures if they had it.)

industry insider

20th May 2016, 09:16

Mitchaa

n the initial report released last week for OJF , you can see a split planet gear in the pictures with a lot of that particular gear I presume still unrecovered? I don't think there's enough there to rule out epicyclic failure and lean towards suspension bar failure personally.

Kawijet

It makes sense - the gearcasing fractured at the point of the upper 2nd stage epicyclic module and thats where the gearbox parted with the MGB. Above this is the conical. So if the conical also parted the upper gear carrier would have fallen free of the rotorhead leaving the splined connector but that is not what you see in that photograph of the recovered rotorhead. It does not taper from the swashplate down to the splined rotor mast like in this instance, but looks the same width right down, due to the conical and upper module still in position.... Does that make sense?

I understand the failure mode of REDL and the consequent fracture and separation.
However, if there was an epicyclic failure of some kind with OJF, it may not be exactly the same failure mode, the separation may not therefore be identical to REDL?

Kawijet

20th May 2016, 11:07

BASys,

Not really sure what you are on about to be honest. Look at the 2 semi circular abrasions on the red and black paint - I said nothing about it being on a different airframe and different colours? What else on a helicopter can cause large radius semi circular abrasion marks other than the rotor?
As for position of the rotor head - you are aware the rotor head completely detached itself from the airframe? So you tell me what position the rotor head was in? Anything is possible as we are not talking about normal running conditions. Look at the blades - they obviously struck the helicopter so its not impossible it grazed the panel as it departed the airframe is it? Not so supernatural or a rediculous thing to suggest....

Mitchaa,

Skotty was spot on with his diagram. Epicylcic gear failure leaves NO room in the gearbox for broken parts and so the gearbox casing gets burst open at the epicyclic ring where the debris gets jammed between planetary gears and the ring gear. It wouldn't burst off the conical housing as that is above the epicyclic. Once the gearcase has fractured open then any rotor torque on the conical housing would be practically 0 as the fractured section is free to rotate seperate from the MGB. Therefor it would not shear here. For this reason I believe the failure WOULD be similar to G-REDL if it was an epicyclic destruction. At least the conical housing remaining. That is not the case here.

It is not easy to see on the G-REDL recovery picture but if you zoom in you can see the edges of the 2 epicyclic gears. I have tried to highlight them for you.

http://s32.postimg.org/4jeduv3r9/G_REDL_close_up.jpg

Never Fretter

20th May 2016, 16:29

In the case of G-REDL the failed gear was propelled like a knife through the casing. That hasn't happened here it seems (the AIB had the epicylic casing in the shed in Bergen).

If the MGB seized totally either the shaft would surely fail in torsion or the splines would be torn off. There is no sign of that or of the tail drive shaft flailing after a sudden stoppage. If there damage like that it is difficult to imagine the AIB would not have said.

Does that mean we can conclude what happened?

No.

Only a fool would try to draw conclusions publicaly on cause second hand.

However I can see how a possible suspension bar attachment failure is worth an AD especially as one servo (the front one) separated and most of the front suspension bar is missing.

Does anyone know if any problems have been found in the rest of the fleet following the AD?

And what news of Shell Norway's action against CHC?

Mekanikeren

20th May 2016, 18:50

My profession is mechanic, more then 30 years with the steel technique, but I can not conclude the cause of the accident on Turøy.
I hope AIBN.no find the cause. I will explain elements called : Problem number 1

A
Fracture surface on the bearingarm tell me that the steel structures is hardened, and the steel toughness is small.
Steel structure change during welding, and the break may have occurred as a result. I do not know if annealing is done.
Ref : Weld is somtime stronger, and the ship Sleipner broke in 2, near the weldplace
It is best to make all suspension bar in one piece. Another factor is whether all suspension bar are vibration and bendtestet
by the manufacturer. Normal procedure by roller bearing assembly is to heat the bearingarm in oil and then assemble the bearing
Normal clearance is some hundredths mm clearance. When bearingarm has cooled then the roller bearing sits completely fixed.

B-C
Probably when the bolt C is mounted into B it will be few hundredths mm clearance, and the result becomes slack. Is there any
slack - vibration damage by E. I guess all the parts are not heated before bolt C is fitted into B. Before the put the bolt to travel block on a drilling rig
the boltis being frozen before assembly. Injuries outside B ?
If shaft C is loose and rotates - vibrates will D change shape. Shown in the picture F.
The locking string has changed shape. This can wriggle out of the shaft or be cut. A missing / broken shaft / part / may result in helicopter crash.
There are many other and better technical solutions then the pictures shown.
AIBN.no present images shown 3 suspension bar and 5 bolts

AW009

20th May 2016, 19:25

@Mitchaa: If you are meaning https://www.google.de/search?q=Torque+case&biw=1280&bih=663&site=webhp&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwj-z9DmrunMAhWFWywKHSErAlYQsAQIHg your satiric humour despite all tragedy is mind-blowing!:ok:

OnePerRev

20th May 2016, 19:25

The upper planet shown has three fracture surfaces, all exactly spaced. Note the heavily smeared inner diameter on the left but absent on the opposite side of the fracture. This indicates roller rotation against a separated raceway. On the question of time, uncertain, but such conditions take more than a few seconds to develop. I would be interested in seeing the fracture propagation direction. If the planet were "squeezed " then fracture starts at ID at two places 180 degrees apart and OD opposite. The lower pictured pinion has one visible fracture likely starting at ID. If all fracture started at ID then it may be a gear vibratory resonance to get uniform 90 degrees away. Otherwise that's odd coincidence.

Never Fretter

20th May 2016, 19:36

Never Fretter,

Explain why the first and 2nd stage gear wheels are found on the opposite ends of the island without a gearbox rupture?

Rumour has it that there's been quite a few loss of torque cases found on the MGB BBQ mounts from various operators around the world. One big red herring in my opinion.

I don't HAVE to explain anything and am rather disinclined as you have your heart set on your pet theory.

But IF the 'top' was pulled of the MGB and the MR had exerted a rearward load until the rear suspension bar attachments failed then it would not be totally surpising to see some gears released.

The island you mention is tiny. You are over imaging the significance of a limited set of debris data!

The AD is not on the barbeque plate attachments. Go look at squib's link as you really need to understand the layout if you are going to persist with pushing your single theory continuously.

Deux Cent Vingt Cinq

20th May 2016, 19:58

I believe there maybe another statement/report from the AIBN next Wednesday.

HBXNE

20th May 2016, 20:51

"Rumour has it that there's been quite a few loss of torque cases found on the MGB BBQ mounts from various operators around the world. One big red herring in my opinion."

If you were logging with the machine or working in a high airframe cycle, (+20 cycles / hour) enviornment, then, yes.

IFR a/c, extremely unlikely.

While logging in CH in the mid '80's we had to implement a 25 hr tq check on the 36 mgbx/bbq plate bolts. The "new" AS/AH bbq plate to fuselage hardware is a 50 hour tq check.
This was based on our experience as well as info on Columbia Helicopters earlier logging experience with the AS332C.

Something that has been bothering me since the a/c went down with no warning. The rotor / epicy / mgbx moduls had been seperated and reassembled in the week (+/-) prior to the final flight?
Was the reassemble of all these components done outside of the airframe and on a 5 degree plate and then as a complete unit installed on the a/c?
Or was mrh assembly replaced on the a/c?
The question that is open for me, did the maintenance engineers use the 5 degree position on the mrh lifting jig to install the mrh/mast in the epicyclic upper case?
There was rumour running around in '83-'84 that in the Gulf of Alaska an AS332 landed on a deep water rig and had a bang during shut down. The epicyclic was damaged. The complete transmission assembly was replaced before the return flight. The fault was traced back to a mrh installation without the 5 degree setting on the mrh lifting jig.
Again, this was a rumour that was circulating at the time.

It is a fact that the epicyclic upper gears do not take kindly to rocking the mast into place without have the lifting jig positioned correctly.

I hope for sake of the engineers that last worked on this a/c that this is not the case.
Marcus

Never Fretter

20th May 2016, 21:20

The only theory I have is that Mitchaa has made up his mind and will ignore any possibility that doesn't match his own. He has and may continue to provide supporting evidence and quiet frankly amusement:)

New evidence from the AIB may well point to one of several possibilities but selective interpretation will only point to self-deception.

Kawijet

20th May 2016, 21:22

Mitchaa,

The gearbox may well have ruptured. Lets just say If the suspension bar failed and caused the rotor to pitch forwards, the stresses imposed on the gearbox would have fractured the gearbox housing for sure. Even when the conical housing failed the remaining suspension bars would have kept the rotor mast splines in engagement for a short time before the struts finally failed releasing the rotor head. During this time the engines would be preventing the gearbox from pitching forwards and the side load on the epicyclic module would be extremely high. It is entirely possible that the epicyclic module casing could have been a secondary failure releasing parts. The primary cause however would be suspension bar failure.

I am still of the opinion that because of the absence of the Conical housing this is a Suspension Bar failure. AH must be sure its not an epicyclic failure also before making such a bold statement as they have done as it is pretty much Reputational suicide if they are wrong! Thats what makes me believe that maybe they are right in this instance. Its not the same failure as G-REDL in my humble opinion..... for all that is worth.

I am eager to hear what the crash report says on this one.
Time will tell.

Satcomm

20th May 2016, 22:23

I don't understand why so many people think AH has made a bold statement. This is not a repeat of anything that has ever happened to the 225. They know it,their lawyers know it and any one in the industry SHOULD know it. IMO, they went to the crash site, looked at the gearbox and hums, easily determined this is not a repeat of the previous 225 failures and issued the statement. From initial scene investigation, probably noted the suspension bars detached (whether failed or ripped from the aircraft) and started by getting all operators to inspect the installation, then report findings.

As for the L2 incident, yes, this is most likely the same type of failure. Again, just my opinion. I've seen pics from 2 rolled over Pumas .... Beat the blades clean off of both machines .... No MGB failure. No housing failure. I think if a suspension bar failed the gearbox would eventually roll right out of the aircraft with the head still attached. The other thing nobody has mentioned is the fact that much like REDL, most of the dampers are let go .... Most likely from the MGB sudden stoppage. The fact that the suspension bar fittings are damaged or broken off is meaningless at this point. They are not meant to take the forces of the MGB failure.

This of course is just my opinion and is meaningless as well!!

Kawijet

21st May 2016, 08:12

Satcomm,

I part agree with what you say but then you kind of go on to contradict yourself.
The AH tech experts that travelled to the crash site must have found some evidence to suggest that this is NOT the same as previous gearbox failures (As in G-REDL's epicyclic failure) as they went from: "we are allied with the decision taken to put all commercial EC225LP passenger flights on hold. " and 48 hours later to "Considering the additional information gathered during the last 48 hours, Airbus Helicopters’ decision, at this stage, is to not suspend flights of any nature for the EC225LP."

So I agree they found something but it is a pretty bold statement to suggest their helicopters ARE safe to fly just a few days after a catastrophic crash as the investigation has barely begun let alone concluded! Thats bold! Unless they are absolutely SURE this is NOT the same as G-REDL in any respect.

But you contradict yourself for the very point I have made above. You say this is most likely the same cause as the L2 (G-REDL) but thats what is so strange about this AH statement. If it was the same failure they would need details of the planetary gear metallurgy inspection report, and the conclusions of the accident report, to make damn sure it wasn't a failure due to a manufacturing defect, for which, they would be directly responsible! So they have to be sure for whatever reason this is not an epicyclic episode again especially at this early stage.

Its because of this, and the differences in the rotorhead seperation, I am inclined to agree with them....

...However, I do agree with you completely on Opinions.... and that one above is only mine. For all that is worth.

Satcomm

21st May 2016, 12:09

Kawijet, REDL was an AS332L2 not a H225. My point is, legally this is NOT a repeat of anything that has ever happened to the H225.

For the statement time lines. AH made its initial statement about being allied while their expert team was on route to Norway. Given the fact that there is a history with the lower section of the 225 (and 225 only) MGB, this was probably a wise thing to do. 48 hours later, travel time and wreckage recovery, they must have seen something to be certain that it was not a repeat of again the above MGB issue. This is when they issued the so called bold statement of it being safe for flight. I believe they also stated at or around this time that this was not a repeat of the issue that cause the "2012 ditchings". No mention of the possibility of it being a similar issue of the 2009 AS332L2 Epi failure.

I do agree that I have made at least one incorrect statement in my last post. When I said this was a "repeat" of REDL. A repeat would be the same type of aircraft with the same part number main gearbox. Neither of which are the case. Again, this will NOT be a repeat of anything that ever happen to the 225.

As someone else mentioned earlier after the AirEgypt crash, is Airbus now suppose to ground the entire fleet worldwide of every A3XX series of aircraft because there was an unexplained accident. How many of the people going off shore today on a S92 got to their heliport via an A3xx series of aircraft and never questioned that.

AW009

21st May 2016, 16:01

For me the core issue is not „had it been a repetition of G-REDL“, because it wasn’t. By a view on the future and the fate of SUPER PUMA, the essential question is, „might the catastrophe of LN-OJF (H225) and a repetition be possible also by an AS 332 L1/L2“?

aheoe26104

21st May 2016, 16:10

AW009

21st May 2016, 16:44

HeliComparator

21st May 2016, 19:30

16 Dec 1980 - SA330J - 9M-SSC - Main rotor separated after A second stage epicyclic module planetary gear fatigue failure- on contract to Sarawak Shell.
01 April 2009 - AS332L2 - G-REDL - Same as above.
29 April 2016 - EC225 - LN-OJF - Main rotor separated ...

Does it matter what the reason is? Seems to be not confined to the 225 / L1 / 330.

If this case was due to a different reason, how much confidence does that instill, how many reasons can there be for the main rotor to separate from the Puma with it's grandfather rights gearbox?

So even if we accept your premise that they're all effectively the same type, 3 gearbox-related fatal accidents in 36 years - which is an awful lot of flying hours. Does any other type have a better safety record? Helicopters are dangerous - GET OVER IT. But not as dangerous as the roads, especially in China. And not as dangerous as smoking/drinking/eating too much. And don't forget that most people die in bed, so going to bed is REALLY DANGEROUS. In fact life is a terminal disease, best not to start on that journey at all as it has only one consequence.

Lonewolf_50

21st May 2016, 20:29

Fareastdriver

21st May 2016, 20:55

I am pretty sure you won't find 3 events where the big fan came off the top since 1980 for the two fleets combined.

The S76 has a similar head to the Blackhawk. So far the S76 has taken nearly 200 lives and I can remember three occasions where it was because of departing blades including one that I had flown the previous flight.

https://aviation-safety.net/wikibase/dblist.php?AcType=S76

There are a lot of 76s around, as there are 330/332/225s. It doesn't make one type more dangerous than the other.

aheoe26104

21st May 2016, 21:57

@aheoe26104: Sorry; I’m allowed to impute to you that you have never been a member of an investigation board. You are making prejudicial comments and you haven’t understood or even haven’t read the representational thread?
The case 'LN-OJF' is too serious and the dignity of the fatilities is too invioable to be discounted by hollow and unprofessional comments instead of substantial arguments and facts!
AW009,
1) I have been involved in 2 investigations in my 34 years experience as a pilot.
2) No prejudice here, I am an big French helicopter fan, most of my experience is on Alouettes III, Puma C, H, L, L1 and 225 - my concern is about the notion that it is acceptable for a helicopter to shed it's main rotor even if it is over a period of 35 years. I have to look my passengers in the eye and assure them that they will not experience the dreadful free fall in a helicopter without it's main rotor.
3) Your comments regarding my understanding of the situation or my reading does not deserve a reply.
4) Fatalities - it is the main reason for my comments, I do not want to see this happen again and from my reading and understanding, all I am seeing, is that positive rectification has not been made and that if we indeed do not show sufficient respect for the deceased, they may have died in vain and their lives will not be dignified by us as the flag bearers of flight safety.
5) "hollow and unprofessional comments instead of substantial arguments and facts!" What do you read in the previous 40 something of pages? Facts? No, we are (supposed) to wait for the AAIB to reach its conclusions and come with recommendations, not try to defend the Puma. That is not our job. The manufacturer or owners can do that, my professional responsibility is first to my passengers and to myself. BTW, all the things I posted are from air accident investigation board findings, so if you would like to go back and tell those they have their facts wrong or unsubstantiated, well be my guest.

aheoe26104

21st May 2016, 22:08

@HeliComparator

While I appreciate your truth about helicopter flying being dangerous, the big fan on the top coming off is a rare event in any model. (And thank the engineers for that!) The US Navy has been flying Seahawks with pretty much the same rotor system now as when introduced. (around 1980ish). That rotor head/system is very similar to the US Army Blackhawk, with a few bits and pieces different due to blade fold accommodation. I am pretty sure you won't find 3 events where the big fan came off the top since 1980 for the two fleets combined.

aheoe26104 asks "does it matter what the reason is?" The implication in that post is "no" and that there is something fundamentally wrong with the design. I cannot arrive at the same conclusion.

I say yes, it matters what the reason is. The reason may have to do with design or not, for this instance.
We'll see.
I don't think the "get over it" was a good response to that post -- even though the many hours of safe and effective operation speak volumes for the model being a good one.

Lonewolf, granted and I respect your opinion. It just seems we have a growing belief that if this accident was due to the poor workmanship during the fitting of the suspension bars (or the technical reason for it's failure), then somehow all the alarmists can sit back and relax and that the 225 and L2 can just return to service with a few minor (or major) changes in procedures. Granted the incidents in history are spread over 36 years, but are we prepared for more of the similar kind of catastrophe, even if the next time is due to yet another new reason? I hope you understand my concern?

aheoe26104

21st May 2016, 22:14

The S76 has a similar head to the Blackhawk. So far the S76 has taken nearly 200 lives and I can remember three occasions where it was because of departing blades including one that I had flown the previous flight.

https://aviation-safety.net/wikibase/dblist.php?AcType=S76

There are a lot of 76s around, as there are 330/332/225s. It doesn't make one type more dangerous than the other.
Fareastdriver, don't be silly. If we had to start counting the amount of lives lost in helicopter accidents, then you may find there are more than 200 lost in the Puma. This is not the point I am trying to make. I accept life leads to death as you would like to over simplify. I just would not like to see more wives and children loosing their loved ones due to an inherent problem that is not addressed properly due to commercial pressure.

AW009

21st May 2016, 22:15

AW009,
...... 2) No prejudice here, I am an big French helicopter fan, most of my experience is on Alouettes III, Puma C, H, L, L1 and 225 - my concern is about the notion that it is acceptable for a helicopter to shed it's main rotor even if it is over a period of 35 years. I have to look my passengers in the eye and assure them that they will not experience the dreadful free fall in a helicopter without it's main rotor. ....

4) Fatalities - it is the main reason for my comments, I do not want to see this happen again and from my reading and understanding, all I am seeing, is that positive rectification has not been made and that if we indeed do not show sufficient respect for the deceased, they may have died in vain and their lives will not be dignified by us as the flag bearers of flight safety. ....

Sorry I provocated You a little bit, but now and with Your very clear statement - I supossed it allready before - You are in total on my frequency! Wellcome also and best regards. A private E-Mail is wellcome.

Bernhard

Kawijet

21st May 2016, 22:30

Satcomm,

I take your point and you do raise some good points.
But things still do not add up. They never said it is similar to G-REDL failure, but, they must be saying that it IS NOT the same, otherwise, how on earth can they state that it is "Safe to fly" without a definate cause or in depth analysis of the epicyclic gears in this case?? How many other airframes are waiting to spit out the rotor mast if it was indeed another planetary gear failure!?

I am aware they are 2 different models yes. However, In reality they are not so different - the 225 being an "upgraded" version of pretty much the same design. And I know this is the first 225 accident of this kind. But for that reason it baffles me even more as to why they would give the green light to fly them. If it is the first of its kind then surely it needs a definite cause before "safe to fly" is stated! Not 2 days of a check over....
Basing their "safe to fly" criteria on a hunch is not good enough (and I am sure they had more evidence than just a hunch!). It doesn't make sense unless they are sure it is NOT an epicyclic failure. That is what I am saying here.

Heres a very flippant recap of their statement to try and emphasize the point:

"We will ground the helicopters following this catastrophic accident. This is not the same gearbox trouble that caused the ditchings. After 48 hours we have now discovered it is safe to fly our helicopters. PS. Better just check your suspension bars and let us know how they are...."

Why would they do that? They are pretty much indicating suspension bar failure here.
They MUST know something we dont and be pretty sure that the investigation will make the same finding.

Again - just my view point on it.

Offshore pilot

21st May 2016, 22:31

HeliComparator

21st May 2016, 22:57

Granted the incidents in history are spread over 36 years, but are we prepared for more of the similar kind of catastrophe, even if the next time is due to yet another new reason? I hope you understand my concern?

No I don't really understand your concern in a rational way. Similar kinds of catastrophes WILL happen. In Super Puma variants and other types. People will die in helicopters for the foreseeable future. I somehow doubt it is particularly concerning for the dead, or those who they leave behind, whether it was due to the rotors falling off or any other reason. A fatal accident is a fatal accident in the eyes of those directly involved. I do feel you are just scaremongering.

Of course we all want to try to prevent recurrences but please lets do it in a rational way, not in an irrational and emotive way.

jimf671

21st May 2016, 23:40

Fareastdriver and aheoe26104,

I think you will find the general pattern to be that most well-established medium and large types have been involved in accidents claiming hundreds of lives. Modern examples like the EC225 and S-92 appear to be well on the way to bucking that trend. Never room for complacency of course.

TylerMonkey

22nd May 2016, 00:09

They have only recovered a very small piece of the front suspension bar. ( plus the upper attaching pin, bearing and nappy pin). I don't see how AH can decide this early that the 225 is totally safe to fly. If they do not have the lower 90% of this Rod and the lower attaching bracket plus it's pin then there is a huge piece of the puzzle missing. What if they find these pieces later and there is evidence of metal fatigue or other failure. It seems to me they are mainly concerned if it is a gearbox problem like previous events. So far they feel it is not and therefore business as usual.

aheoe26104

22nd May 2016, 00:26

Bottom line for me is that it is not possible to put your passengers at ease without facts. AH's early response to this tragedy will not help to restore the trust.

AW009

22nd May 2016, 08:20

… AH's early response to this tragedy will not help to restore the trust.

@aheoe26104: I’m absolutely going along with you.

@all: Furthermore I have definite views on the possibility that the very early statement of the spokesman of German Luftwaffe (as quoted in http://www.pprune.org/rotorheads/578298-ec225-crash-near-bergen-norway-37.html#post9376505) might have its sources also in AH (AHD) being the the 'purveyor' of German FMOD.

The line between genius and insanity is a very fine one. But out of my technical view, the „suspension bar solution“ of (SUPER) PUMA - as realized by AS/ECF/AHF - might be genius, but is'nt at all ingenious (please compare http://www.pprune.org/rotorheads/578298-ec225-crash-near-bergen-norway-31.html#post9372108).

AS 330 had been a design for a MTOW of approx. 7,5 to, now H225 is approaching 12 to.

The ’footstool’ must have legs and fittings being dimensioned to present forces, loads and vibrations and must have four or five legs (due to harmonically oscillations and well-balanced forces) whichever we are talking about H 225, H215 or AS 332L1/L2,

A barbeque plate being semi-elastic fixed is nice, but where are the 3-dimensional dampers?

Have anybody ever heard of an exploded housing of an automatic transmission of a motorcar? Really not, because the caves of epicyclics are not the housing, repective are isolated from the housing of the gear box.

For me (Super) PUMA is a mirror image of the french spectrum „savoir vivre“ to „laissez faire“, but the times of “Saint-Exupéry“ in aviations are since 7 decades over and it seems “Super Puma“ being 5 decades old will become the very same myth.
(see https://books.google.de/books?id=Ya5ECwAAQBAJ&pg=PA11&lpg=PA11&dq=Fred+Firestone+helicopter&source=bl&ots=wSg1Mvjdw8&sig=4jfwooHHp2nLDOzgiklk02Hua-c&hl=de&sa=X&ved=0ahUKEwijn4rjne3MAhVrAsAKHSLbDH4Q6AEIHzAA#v=onepage&q=Fred%20Firestone%20helicopter&f=false):p

Lonewolf_50

22nd May 2016, 11:35

@fareastdriver
It doesn't make one type more dangerous than the other.
That is not the direction I was heading, in fact I was heading in the opposite direction. Two separate points: models with millions of hours of operation. (Both well seasoned/mature). How incredibly unusual it is that the rotor system comes off. Thus "bad design" and "that model's all wrong" is the idea I was addressing and calling in to question. There are a lot of different ways for things to go wrong in a helicopter.

aheoe26104
I hope you understand my concern? Absolutely. With passengers/customers/ those not in the industry the modern knack for "truth by sound byte" makes people impatient to find the cause. Finding the cause of this tragic crash is important for future lives. Once the investigators get a good grip on it and can inform the public of their findings, whoever operates a helicopter (not just a Puma) can assess "what are the things we can do here so something a lot like that it doesn't happen here?"

I also appreciate the crisis in confidence among off shore workers, until more focused causal factors can be determined.

Satcomm

22nd May 2016, 12:30

Kawijet,

Based on above, I raise you this one. Why initially only the 225 and why now only include L2 if it was determined to be suspension bars? There are still plenty of L/L1s flying around in the world.

Also, the Flight authorities have ground the aircraft not AH. Who's footing the bill at this point. I really have no idea but I'm guessing that means AH are not currently on the hook finically for all the lost revenue. If they ground it they are probably are.

bleuciel

22nd May 2016, 13:23

I believe we soon will get more information from AIBN and Airbus based on fact. FDR/CVR and most of the essential parts are recovered while search continue. Airbus may have their theories based on findings so far. Probably they can not publish theories until AIBN agree. Internal MGB malfunction would be very serious for the future of the EC 225 in the North Sea and worldwide. Suspension bar / fitting issue will be more easy to correct within a short time frame.

I would love to see the 225 flying again, and fly it as well. My problem though is that who can trust Eurocopter/AH any more? When the first 225 ditched, EC said it was a bad batch. They didn't go in depth. A very quick and convenient solution.

Then when the second one ditched, I guess they swallowed their tongue. But they said in their initial statement that "the pilot elected to land the helicopter into the sea" (or sth like that, they definitely used the word "elected").
Then they spent so many months to see what was wrong with it, and then used a couple of universities to confirm their theory. And they probably did find the reason. And then they spent so much money and time to convince everyone that the 225 was safe. And it probably was.

But who can trust their statements any more? What if they are looking for a quick and convenient solution again?

TylerMonkey

22nd May 2016, 13:55

Must have been no documented proof (emails etc?) that Bond told them this fact . . .

Hard to imagine in this tech age.

" When in trouble hide... If they find you .... lie . "

squib66

22nd May 2016, 13:57

You are mistaken Mitchaa, the cracks were not in identical locations (though they were near-by).

Why did Eurocopter allow this 2nd failure to happen? What was being done in the months between May and October to protect the remaining 225 fleet? Why didn't Eurocopter identify the issue correctly?

As the AAIB explain in their report, the corrosion in the G-REDW case was believed by all the parties to the investigation (prior to G-CHCN), to be linked with a tiny production anomaly in a countersunk hole in one batch of shafts. The AAIB list 7 actions that Eurocopter took to address that.

In contrast, to show a really inadequate response, the first S-76 fatal accident (PT-HKB (https://aviation-safety.net/wikibase/wiki.php?id=33292)) in which 14 died after a main rotor blade came off occurred less about a year before another 4 people died due to an identical failure (G-BGXY (https://aviation-safety.net/wikibase/wiki.php?id=31902)). In this S-76 case a key inspection requirement was dropped from the Service Bulletin after PT-HKB, and despite the FAA chasing Sikorsky, they had not acted by the time of the UK accident.

G-REDL Bond said they told Eurocopter that the chip had come from the epicyclic plug. Eurocopter denied this and said Bond had told them it had come from the main module sump.

Eurocopter were no doubt confident they were told the debris was found in the sump because when debris is found on the epicyclic detector the epicyclic module has to be opened and the magnets examined. The operator did not follow the MM requirement to do that and therefore was unable to tell Eurocopter anything about the magnets. The absence of that data would reinforce a misunderstanding at Eurocopter that the chip was found in the sump.

The operator was of course aware of where the chips were found and what maintenance they had and hadn't done, which they found it impossible to explain at the Fatal Accident Inquiry.

n305fa

22nd May 2016, 21:20

You are mistaken Mitchaa, the cracks were not in identical locations (though they were near-by).

As the AAIB explain in their report, the corrosion in the G-REDW case was believed by all the parties to the investigation (prior to G-CHCN), to be linked with a tiny production anomaly in a countersunk hole in one batch of shafts. The AAIB list 7 actions that Eurocopter took to address that.

In contrast, to show a really inadequate response, the first S-76 fatal accident (PT-HKB (https://aviation-safety.net/wikibase/wiki.php?id=33292)) in which 14 died after a main rotor blade came off occurred less about a year before another 4 people died due to an identical failure (G-BGXY (https://aviation-safety.net/wikibase/wiki.php?id=31902)). In this S-76 case a key inspection requirement was dropped from the Service Bulletin after PT-HKB, and despite the FAA chasing Sikorsky, they had not acted by the time of the UK accident.

G-REDL

Eurocopter were no doubt confident they were told the debris was found in the sump because when debris is found on the epicyclic detector the epicyclic module has to be opened and the magnets examined. The operator did not follow the MM requirement to do that and therefore was unable to tell Eurocopter anything about the magnets. The absence of that data would reinforce a misunderstanding at Eurocopter that the chip was found in the sump.

The operator was of course aware of where the chips were found and what maintenance they had and hadn't done, which they found it impossible to explain at the Fatal Accident Inquiry.

I think your doing the REDL investigation a major disservice by selectively quoting part of the report the suit your argument. The issues around the discovery of the particle are clearly described in detail in the report, in summary, for various reason BOTH bond and EC made assumptions based on incomplete information.
Steps were taken to prevent it happening again which are clearly explained in the report.

I would also say that based on the report and the AAIB's testomony to the FAI, the AAIB do not support the EC/AH theory of 'pure' spalling that wasn't picked up by the operator. I for one would tend to support the AAIB view for two reasons, 1) they are independent and are not subject to commercial pressure, 2) they have access to information and expertise beyond that provided by EC.

AW009

22nd May 2016, 21:58

One should reconsider the excuses of Airbus Helicopters on the incidents and disturbances of the NH90. Especially this applies to Cat-A / PC-1 and HHO of SEA LION. The reader will recognize much about the mentality and philosophy of Airbus Helicopters.

squib66

22nd May 2016, 22:20

n305fa

I advance no theory. Mitchaa commented on a difference in recollection between operator and EC in 2009.

Undisputed facts are that in that case the operator did not follow the MM instructions for debris on the epicyclic magnetic chip detector, did not follow the written EDR process and continued to fly the aircraft after the debris having misidentified ferrous debris as non-ferrous.

So undisputed in fact that the FAI concluded:

Bond’s maintenance and inspection failures, which it readily admitted, were
• A failure to follow the correct task in the aircraft maintenance manual on the discovery of a metal particle, or “chip”, on G-REDL’s epicyclic chip detector on 25 March 2009, which would have resulted in the removal of the epicyclic module and an examination of the magnets on the separator plates;
• A failure to ensure that communications with the manufacturer of the helicopter on 25 March 2009 were done in accordance with the recognised procedures, with the result that misunderstandings arose between the parties, which contributed to the failure by Bond to perform the correct task;
• A failure to identify the nature of the substance of the metal particle when on 25 March 2009 performing a specified task in the aircraft maintenance manual and in doing so might have lost the opportunity to avoid the consequences of its failure to perform the correct task.

The AAIB did in fact determine that the debris, and failure to recognise it as a sign of degradation of the epicyclic gears (p112 of the 115 page report which you are now selectively quoting), was contributory.

However, there is no actual evidence to suggest the discussions of 25 March 2009 are relevant to LN-OJF, though I can see how it might suit some people.

riff_raff

23rd May 2016, 00:00

The line between genius and insanity is a very fine one. But out of my technical view, the „suspension bar solution“ of (SUPER) PUMA - as realized by AS/ECF/AHF - might be genius, but is'nt at all ingenious

This brings up an interesting point. There was some discussion of design issues with the H-60/S-76/S-92 main rotor drivetrain. One thing I would point out is a fundamental difference between the design of the main gearbox structural attachments of the H-60/S-76/S-92 versus the EC225 in terms of fault tolerance. The Sikorsky design transfers rotor loads to the airframe using the gearbox housing, while the EC design transfers most rotor loads to the airframe using a set of struts. Both Sikorsky's stressed housing and EC's strut arrangements are attached to the airframe at three locations, and failure of just one of the three attachments would likely be catastrophic. If you take a close look at the picture of an S-92 main gearbox below, you'll note that the airframe attachment uses two bolts at each location, which provides single fault tolerance capability for this flight critical fastener function. The single clevis pin used at each end of the EC225's struts has no fault tolerance capability.

It might be possible to make the EC225 strut arrangement fault tolerant if two independent struts could be used at each of the three attachments, where one strut is capable of continuing safe operation in the event the other strut fails (assuming of course the kinematics of the system can be made to work properly).

http://www.tsb.gc.ca/eng/medias-media/photos/aviation/a09a0016/images/photo_5.jpg

Satcomm

23rd May 2016, 00:27

Rif raff, Sikorsky uses 4 points of attachment for their "stressed" gearbox. Also, the S92 is on phase 3 of it main gearbox. There have been failures (cracks found) of mounting feet and in fact are still quite closely monitored by HUMS. Not much point in have 2 bolts when the entire foot is detached from the gearbox. Seems they have finally nailed it now though and luckily there were no accidents in the process, no more cracked feet, however, I believe there have been a couple frame issues since.

Every manufacture out there could make a helicopter that would never fail, problem is it would never get off the ground. Hey why not throw an extra motor in, then we would never have to worry about single engine performance either.

jimf671

23rd May 2016, 00:51

... ... the airframe attachment uses two bolts at each location, which provides single fault tolerance capability for this flight critical fastener function. The single clevis pin used at each end of the EC225's struts has no fault tolerance capability.

I am not sure it works quite like that. For one thing, we've been told there are two retaining pins on the end of the clevis. For another, we already know that bolts in the MGB assembly have not been Sikorsky's strongest suit.

Lonewolf_50

23rd May 2016, 02:29

@jimf671
Comment deleted, Satcomm caught my thinking about the wrong bolts.

Satcomm

23rd May 2016, 02:50

Lonewolf, I think Jimf671 was referring to the S92 AD asking operators to check the main gearbox mounting bolts. Here is the reason copied from the AD.

"The FAA received a report of a failure of a main transmission mounting bolt, detected during routine maintenance inspection. Undetected bolt failure could result in loss of support of the main transmission, and subsequent loss of control of the helicopter."

AKA: gearbox detaching from airframe with rotohead attached ... Same undesired result.

The oil filter studs were a totally different issue.

The main gearbox mounting feet with the "2 bolt redunanticy" were also responsible for several ADs. 2 bolts in a single foot is not really redundanticy, when the foot breaks off you just have 2 useless bolts in the frame rather then 1.

buzz66

23rd May 2016, 04:28

L & L1 good to go
EC225 no good and now L2 no good.

Pretty hard story to sell if you ask me!

Are the SUS Bars and Gearbox's that much different between lets say an L1 and an L2? I would think not.

Is it because an L2 and 225 are heavier?

Is it just Risk tolerance?

Is there a "b Omega" issue they are not talking about?

Is it because of the Articulated Head design?

Explain why if Airbus suspect a Sus Bar failure would the L and L1 be allowed to fly and the L2 and 225 not?

Noiseboy

23rd May 2016, 05:38

With the shaft breaks, AH said it was a bad batch, which it was due to moisture retained after manufacture, they modified the plug to prevent this from happening. They were absolutely correct in their initial statement.

The second break of the same part was due to the build up of the 'mud' as they called it, which also contained moisture, this was an old part, almost through its second life, and the presence of the mud introduced corrosion that the original design testing had not taken into account.

It was the operators and oil industry who brought in outside agencies to verify AH conclusions which they agreed were correct, and in hindsight the prolonged grounding was not necessary since both cracks could be explained and avoided, this then led to an L2 making an approach to Sumburgh the next year. That should have been a 225, which either would have been direct to ABZ or the aircraft would have done what the PNF failed to do and stop the aircraft flying into the water.

I'm not advocating blind faith in AH, but the way the story is told in previous posts is not accurate, and given that AH designed and manufactures these things, and will have been involved in every failure of these things, they will have the most data to come to conclusions more quickly.

Apate

23rd May 2016, 05:39

I think Airbus should be praised for finding the root cause so quickly. What a shame the AIBN and AAIB, Norwegian and UK CAA are all taking SOOOOO long to come to a similar conclusion :}

riff_raff

23rd May 2016, 06:00

2 bolts in a single foot is not really redundanticy, when the foot breaks off you just have 2 useless bolts in the frame rather then 1.

That's not correct. What I stated is that having two bolts at each attachment, where one bolt would be capable of providing continued safe operation should the other bolt fail, provides single fault tolerance for the fastener function. In terms of fault tolerance, this is considered independent from a failure of the associated housing structure. Two bolts are used at each flight critical attachment because failure of one bolt is considered to be a possible event, while structural failure of the housing is considered to be an extremely improbable event.

RVDT

23rd May 2016, 07:31

is considered to be an extremely improbable event

Which Sikorsky had no problem convincing the FAA of until...........................:D

birmingham

23rd May 2016, 08:28

When more than 100 people were killed on Piper Alpha there was a massive HSE revolution. It changed the perception of acceptable risk in the NS for ever. That's the way it is in the oil business - my opinion or anyone else's can only be that.

This very unfortunate run for the Puma will have the same effect in Helicopter operations. People who think this is just another inevitable fatal accident are missing the point. The passengers aren't really interested in the fact that this latest incident was or was not caused by planet gear failure, suspension bars, bevel gear, vortex loss of control or anything else. They simply will not tolerate 5 hull losses in seven years. A line has been crossed. If you don't get that then you don't get NS HSE culture.

The pax know helicopter accidents are inevitable, they also know many good men and women already dedicate themselves to helicopter safey. But they will require, and will get a further step up in safer flying. So at least one good thing will come out of this tragedy.

HeliComparator

23rd May 2016, 09:28

...They simply will not tolerate 5 hull losses in seven years. A line has been crossed. If you don't get that then you don't get NS HSE culture.

So is NS HSE culture based on hard science and fact, or on emotion and hysteria? If based on hard science and fact "it" will be aware that dumping a well tried and tested family of helicopters, for unknown and barely tested new models, cannot be considered a safe thing to do for with ABSOLUTE CERTAINTY the new models will contain some "gotchas" just as the previous generation did (S92, EC225, AW139 etc). So do tell us, is NS HSE culture really so ignorant and stupid as to want to promote dumping the existing fleets and replacing with brand new types?

Personally I would rather continue with well used fleets whose bugs have nearly all been identified and fixed, rather than starting the process all over again with the sure knowledge that there will be near misses at best, fatal accidents more likely, as the new fleet's bugs are ironed out.

Of course what is at the bottom of this is that current certification standards are not fit for purpose. Far too bureaucratic and lacking in good engineering practice (common sense if you like) with far to many design points dismissible by playing the "extremely remote" card when there is zero evidence that such a failure will be extremely remote. And anyway, with a large fleet flying a lot of hours, it is by definition only a matter of time before "extremely remote" events happen.

Let us remember how probability works. If an event is 1 in a million it doesn't mean it will happen on the 1 millionth time. It might never happen in the lifetime of the product. Or it might happen on the first time. So the certification standards consider catastrophic failure inevitable (given enough exposure) and therefore the loss of the odd human acceptable.

HeliComparator

23rd May 2016, 09:31

I think Airbus should be praised for finding the root cause so quickly. What a shame the AIBN and AAIB, Norwegian and UK CAA are all taking SOOOOO long to come to a similar conclusion :}

Could you explain why EASA are happy to allow the EC225 to continue to fly?

I suggest that UKCAA and NCAA are taking a pragmatic line that avoids confrontations with the workforce etc, and of course on an individual basis is probably a consequence of that worst of civil service diseases - arse covering.

birmingham

23rd May 2016, 10:27

Helicomparator;

You asked ...

"So is NS HSE culture based on hard science and fact, or on emotion and hysteria?"

All four play a part as does corporate attitudes, media pressures and trades unions.

Hard facts are only part of the process.

HeliComparator

23rd May 2016, 11:11

birmingham

23rd May 2016, 11:45

Flawed certainly but by no means ineffective. A lot of the response to Piper Alpha was emotional even hysterical but it undoubtedly made the industry safer, faster. We both agree that the helicopter industry's certification system is not without its own flaws.

The E&P industry is well used to external pressures, often emotional, unreasonable, even hysterical. But the likes of Statoil and Norske Shell don't simply dismiss it as irrational. They have come to understand the damage it can do, so listen, learn and respond and it has made them better organisations for it.

A big chunk of the workforce is spooked, this will need to be addressed not just explained away.

jimf671

23rd May 2016, 17:13

As someone who has spent several decades trying TRYING to teach the British how to use nuts and bolts, I have been concerned about both of the fastener problems that have been highlighted on the S-92 box.

The oil filter stud problem indicated a very poor decision about materials.

I am aware of the main gearbox mounting bolt problem but I don't know any of the detail. I would be grateful if someone can direct me to documents with more detail about that failure.

PlasticCabDriver

23rd May 2016, 18:29

Could you explain why EASA are happy to allow the EC225 to continue to fly?

Presumably for the same reason that EASA haven't grounded all the A320s or EC145s recently. EASA will ground a type when they have a reason to do so, not when they don't have a reason not to.

If EASA grounded all the 225s and then subsequently the investigation into LN-OJF cannot come up with a definitive answer, do we then leave all those dozens and dozens of 225s to rot over one mystery incident? Very hard to undo a grounding without a good reason why.

3 weeks ago an EC225 crashed killing everyone on board for an as yet unknown reason.
5 days ago an A320 crashed killing everyone on board for an as yet unknown reason.

How many offshore workers have since flown out of/back to Aberdeen on A320s without a murmur?

Ask them to get on a 225: "no chance"!

Jdbelo

23rd May 2016, 18:54

The AIBN has initiated an extensive investigation and a massive search for components from the helicopter both on land and in the sea. Most of the wreckage is retrieved from the sea and is already the subject of examinations.

Latest update: 23.05.2016

Twist & Shout

23rd May 2016, 19:57

3 weeks ago an EC225 crashed killing everyone on board for an as yet unknown reason.
....5 days ago an A320 crashed killing everyone on board for an as yet unknown reason.

How many offshore workers have since flown out of/back to Aberdeen on A320s without a murmur?

Ask them to get on a 225: "no chance"!

A few points:
We know without a doubt the reason the EC225 crashed: the entire rotor system detached. (The cause for the detachment is under investigation.)

If over the last decade two A320 variants had been found in the ocean, 15nm from their wings. Then 3 weeks ago someone filmed a pair of wings flying down like sycamore seeds, with smoke rising from a crater in the distance, then maybe they would be grounded and/or the traveling public might vote with their feet.

chance it

23rd May 2016, 21:28

A few points:
We know without a doubt the reason the EC225 crashed: the entire rotor system detached. (The cause for the detachment is under investigation.)

If over the last decade two A320 variants had been found in the ocean, 15nm from their wings. Then 3 weeks ago someone filmed a pair of wings flying down like sycamore seeds, with smoke rising from a crater in the distance, then maybe they would be grounded and/or the traveling public might vote with their feet.
Vote with their feet to what exactly ? You know that an S92 / 189 / 175 is safer do you ? So 5 million flight hours 332/225 and 4 million flight hours 330 , Cumulative 9 plus million hours on Pumas ..... Yet get on a 225 ....NO CHANCE ! Well to be honest I don't fancy my chances getting on anything else ! and as an ex LAE on 332's and now until recently , flying on 332/225 on the North Sea I do know the aircraft pretty well .
We have to get real for a moment , the reliability rate we have come to enjoy from the Puma which has been honed over many decades of experience doesn't come overnight , the bare facts are helicopters are not risk free.... It is not a fixed wing aircraft yet we have become complacent at this aircrafts exemplary service and expect our rotating mass of nuts and bolts to perform like a 737 day in , day out . To which largely the 225/332 does better than anything else in its class even to this day .
3 cases of rotor head detachment in 9000000 hours flying , 2 of which were MGB epicyclic planet gear 2nd stage bearing's , However the MGB was trying to give warning by making metal for a couple of weeks beforehand that were ( for different reasons) unfortunately misdiagnosed and 1 where we don't quite know yet , but we do know that there was no issue with CWP / Marms beforehand and an intact epicyclic ring gear in the wreckage , so nothing like the 2 earlier accidents, yet all this hysteria .....! I'm just glad I get to sit out the remainder of my career in an Aircraft that the 'REAL' experts deem to be the safer option ...........because no matter what you think of the the puma/225 the fact is there is NO better alternative ......Simple .

roundwego

23rd May 2016, 21:38

Satcomm

24th May 2016, 01:16

Riff raff, while I can't truly argue the fact that 2 bolts are better then 1 and that it does add some form of redundancy, the fact of the matter is, we are on phase 3 of the MGB because of mounting foot issues. Which in at least one (phase 2) incident resulted in complete separation of one foot. At which time, the second fastener adds no redundancy.

Now, you kinda condradict yourself a little as well. You made the following statement about structural failure, "structural failure of the housing is considered to be an extremely improbable event." Yet it seems you strongly believe that the suspension bars are at fault or at least believe that they should require some form of redundancy. Even if this was determined to be suspension bar failure, which is yet to be determined and was not determined to be a fault in the previous accidents, wouldn't that as well fall into being an extremely improbable event?

Twist & Shout

24th May 2016, 02:11

Chance it

Welcome to the forum.
Thanks for your first post.

Nice support (rant) of the EC225.
I have a reasonable number of hours flying Pumas and EC225s I'm a big fan.

You seem to have missed the point of my post, which was only to address the perceived different approach regarding the A320.

industry insider

24th May 2016, 04:41

Chance It

but we do know that there was no issue with CWP / Marms beforehand and an intact epicyclic ring gear in the wreckage , so nothing like the 2 earlier accidents, yet all this hysteria ...

You seem to know more than AIBN, Bristow, CHC, Babcock, UK CAA and NCAA combined. Please tell us more.........

chance it

24th May 2016, 06:42

Chance It

You seem to know more than AIBN, Bristow, CHC, Babcock, UK CAA and NCAA combined. Please tell us more.........
Data from the CVFDR that was recovered indicated that there were no CWP warnings immediately prior to the detachment . This was in the preliminary report . In the REDL incident they had XMSN chip and MGBP illuminate prior to the gearbox / head separating . If you look through the photos of the wreckage you will see the intact epicyclic module casing.

birmingham

24th May 2016, 07:42

chance it

I think if there was significant evidence that this was a carbon copy of G-REDL (or the two bevel gear incidents) AH would not have made the statement that the 225 is safe to fly.

I also think it likely that the AIBN would have alluded to such evidence by now to justify the continuing ban.

They would also have shared that evidence with other regulators who would likely have introduced bans of their own.

So the cause remains undetermined for now. The latest from the AIBN is "most of the wreckage is recovered" - hopefully including the missing lift/suspension bar and associated components. That is encouraging as it suggests they will ultimately be able to point to the primary cause with more authority than if components were at the bottom of the sea.

Like you, I believe that this latest incident can be analysed and measures be brought to bear to resume flying these aircraft which, viewed over their lifetime, have a very good safety record by the standards of medium weight helicopters.

I also agree that switching to the S92 or some newer types not yet in service will not in any way guarantee a safer ride and an accident free future is a completely unrealistic expectation.

However, the short-term problem is that the Puma's safety record in the NS in the last seven years is nothing short of appalling. Whether they will continue to be part of the solution in the NS E&P business only time will tell.

I first flew in a Puma in 1974 and like you would willingly do so again, but it is not you and I that AH need to convince.

Subsea

24th May 2016, 14:06

http://www.aibn.no/Aviation/Investigations/16-286?iid=19746&pid=SHT-Report-Attachments.Native-InnerFile-File&attach=1

industry insider

24th May 2016, 21:39

Subsea

The report was posted nearly 2 weeks ago, you are a little behind the times. There is a lot of discussion about it on the thread, maybe a good idea to read before you post?

Chance It

You make a good point about the CWP but I am surprised that the departure of the whole MRH wouldn't generate some kind of warning light, although the poor unfortunate crew would not have noticed it.

Would you be able to show the intact epicyclic module picture for me?

AW009

25th May 2016, 00:00

Reliability is in a certain way calculation of risks, also of nerve and confidence. You would never exclude any risk in helicopter aviations and especially not in Offshore Ops by 100%. But when the whole matter becomes incalculably out of a view of your pilot skills and volatile under technical aspects, it is hubris, or even foolishness and ignorance of untrustworthiness.

The (SUPER-) PUMA might be (or might have been) a super helicopter, however in present stage of investigations and their up to now open results, in my opinion the risks are incalculably and irresponsible.

Let us all hope in very clear results and positive solutions, the sooner the better. The contraries must not be discussed, because then consequent decisions are required and are on schedule, also in the sense of the current states of technology and science. Therefore an attitude of professional scepticism is required, not an infringment of technologogical neutrality. .

tenfour

25th May 2016, 05:59

Hi folks,

I've been a long-time lurker, but thought I'd join upon hearing the sad news of yet another NS chopper downing. I am not a pilot and nor do I work in aviation (I'm a legal advisor in Oil & Gas), so I can only look up to you all - especially the chopper drivers - as my heros. Alas, the furthest I got was my gliding wings in the RAF cadets. I have always had a fascination with aviation though.

I am sickened to the stomach that in 2016 and 50 years since we started extracting oil in the NS, that we should still be having these all too frequent tragic losses of life.

It is regretful that CHC have now filed for C11 because frankly it seems like a lottery between the three players - CHC, Bond and Bristow - as to whom will next suffer a loss.

I understand that there is an element of risk with any aircraft; after-all, there are so many things that could theoretically go bang. But my question is this: would the operators allow this frequency of failure or this level of calculated risk on a well-head or a production facility?

Perhaps I am over-simplifying the issue, but it seems to me as a by-standing lay person, that there is an unacceptable frequency to any chopper incident in this industry, which I cannot help but feel that if such incidents were to directly impact production/revenue, they genuinely wouldn't happen ever again.

It's been a while since I have let any aviation contracts, but last time I checked, the value of a human being was about USD$10m and in general, the chopper carriers are insured against loss of life to around USD$50-100m. Hence, a chopper downing needn't necessarily bring down the carrier (CHC notwithstanding) and the client can go about its business as usual after the de-rigueur HSE hand-wringing and knee-jerk media sorrow.

On the other hand, the ramifications from an oil spill... Well, you've seen what happens there. The current bill for Macondo is roughly USD$25bn, with the cost for the loss of 11 souls being but a drop in the ocean (so to speak). And only a giant like BP could sustain this sort of exposure.

Accordingly, I refuse to accept that the downing of a chopper cannot be prevented. And while accidents do happen, I regret that it appears they happen more when the ramifications are cost-manageable; human life seemingly just a costed portion of the risk to the business.

RIP.

Hughes500

25th May 2016, 07:11

I have nothing to do with NS but my AOC auditor who used to be a quality auditor for Jag/landrover came up with an interesting view on how we as an industry wave 2 fingers at safety. As he said if a car crashes or catches fire and it is seen as as a fault in design / manufacturer there is an immediate recall of those vehicles e.g. recently Toyota recalled millions of vehicles and modified for free. Do we see this sort of reaction in our industry, do we f..k. The attitude seems to be it will be all right just keep flying it and by the way it is the owners / operators problem ! As an operator I can vouch for how OEM's and regulators don't really take safety really seriously despite their protestations.

Sanus

25th May 2016, 07:51

Tenfour, nice thought provoking post.

It probably is simply wrong in 2016 to accept an aircraft that is suspended in the air by just three attachments knowing that failure of one attachment would be immediately catastrophic. To accept that "it hasn't happened before" is of little comfort. By comparison the S92 has four attachment feet. When these feet, on the early MGB's, were experiencing cracks Sikorsky confirmed any one of the feet could become totally severed (detached) and the aircraft will continue to fly for up to 30 hours before other attachment feet become over-stressed. This condition would be detected early by a special HUMS tool.

Does that make an S92 safer than an EC225? Cougar may argue otherwise.

All helicopters will have some inherent weakness when compared to other models. The ideal is to get all the best features into one aircraft. But who pays for it.

The EC225 is cheaper than an S92. The AW189 is much cheaper than an EC225. There's little doubt that as in life the same applies to helicopters - You get what you pay for.

tenfour

25th May 2016, 09:14

That's just it though, Sanus - you get what you pay for!

Hence, if I decide to buy some cheap mountaineering equipment and go for a hike up Everest, then I can reasonably expect that my subsequent death from exposure was due to my tight wallet: I got what I paid for instead of buying the expensive kit that all the expert mountaineers recommended me to buy, due to its top of the range technology etc.

So let's apply that model to helicopters; only this time, I'm bringing along a budding employee to my Everest expedition. Sure, he's had all the training etc, but unless I provide him with the best kit...

Now of course, I'm not for a minute suggesting that our colleagues are being flown from platform to platform in Acme Helicopters Ltd products; today's choppers are developments of millions of flying hours etc. But here's another question: are these choppers designed from the ground up for offshore applications? If they are, then any accident as a result of technical failure can only be seen as a failure of the aircraft and its manufacturer: it is simply not fit for purpose. If the answer is no and these choppers are modified to operate in world's harshest environments (i.e. offshore), then the operators ought to be bloody ashamed of ourselves for allowing their people to set foot in sub-optimal solutions. Either way, we clearly do not have a fit-for-purpose solution.

As I said above: one technical-induced accident is a tragedy; any more is unacceptable.

So in essence, when I step onto a helicopter in order to be transported to my place of work, I should damn well hope that my boss hasn't 'got what he's paid for' with his helicopter!

At the risk of derailing the thread, we cannot know what went wrong until the full report has been released, but for the time being, I think we as an industry have every right to make a damn big fuss about a persistent re-occurring issue which results in some kid's Dad not coming home at night.

212man

25th May 2016, 09:35

But here's another question: are these choppers designed from the ground up for offshore applications? If they are, then any accident as a result of technical failure can only be seen as a failure of the aircraft and its manufacturer: it is simply not fit for purpose. If the answer is no and these choppers are modified to operate in world's harshest environments (i.e. offshore)...

Firstly, I would argue that the offshore environment is by no means the harshest that helicopters operate in. As an example, a 70 kts wind creates a very harsh environment for people trying to work on a platform and/or plane and deplane from a helicopter, but for the aircraft itself it's a totally benign situation.

Secondly, it is not realistic for helicopters to be designed for one role only in the civil market, with its relatively (compared to the military) low production/sales volumes. The 225 is a variant of a military type but how that is relevant in this context is unclear to me. Other types such as the AW189, AH175, are designed for the civil market but have to capture a range of operations across a wide spectrum - air ambulance, police, SAR, VIP etc. but, again, it is not clear in the context of your assertions why that has any relevance.

birmingham

25th May 2016, 09:37

Sanus could you or someone in the engineering community help me with this ...

We all know that achieving redundancy with MGBs and MRHs by it's very nature is in most respects impossible. So we take the view that we must engineer it until the point that failure becomes "extremely improbable"

The three suspension bars that are getting a lot of attention at the moment accept, as I understand it, >11 to of lift forces. They also are subjected to downward loading resulting from the mass of the helicopter itself.

Some types are engineered so as some of the lift forces are taken by the MGB casing (which I guess would have both safety advantages and disadvantages compared to using the suspension bars) but that isn't the case with the Puma - is that true?

Is is also a fact that the failure of a single one of the three suspension bars or associated components could really lead to this?

I appreciate that it is "extremely improbable" for this to happen as I am not aware of any tragedies (including this one so far) that have been found to have this as the primary cause. But there are a number of possible failure modes including ...

1. Maintenance
2. Manufacture
3. External damage

and certainly more.

If something can happen it probably will ... and maybe ,extremely improbably, it has ...

So what is the redundancy? - if one goes west is a catastrophe inevitable?

Is it impossible to build in redundancy? Is there redundancy already built in? or are we relying on extreme improbability?

The views of someone with a decent Puma engineering background would be appreciated.

industry insider

25th May 2016, 10:22

212

Other types such as the AW189

Wasn't the 189 a derivative of the 149 which was designed for the military market?

212man

25th May 2016, 10:29

Technically yes, so maybe not the best example, although both are evolutions of the AW139 - which was not military - and designed to CS29/Part29 from the outset.

EESDL

25th May 2016, 17:53

I think that is exactly the point Tenfour is making.
OEMs 'hedge' their production bets and compromise to ensure chopper sells across various sectors - rather than the O&G customers insisting - and paying the inevitable premium - for on an operator to use a machine that has been specifically designed to fly extended periods of time where, currently, if you do get a warning the only precautionary options are limited to ditching.
It will mean an extraodinarily-expensive machine when compared to a standard model.
However, this will never happen as the meticulously-costed Safety Case permits the use of 'compromised' machines in the cost-based analysis.
We all know that the helicopter logistic element is minuscule in the great scheme of O&G.
If clients stopped trying to do it 'on the cheap' - by using modified general purpose machines - then maybe the magnitude of investment would stop the cavalier chopping and changing of contracts for 'convenience' purposes and the industry might make some serious progress when it comes to flight safety.
You rarely hear of companies using 'compromised' installation designs - each installation specialises in a specific task; be it exploration, production, storage, pumping etc
What has been alluded too is that this will not change until the client's cost of a life is significantly increased.
That is one of the reasons why I am grateful that my exposure to the O&G mentality was relatively short-lived!

lynnx

25th May 2016, 17:58

lynnx

25th May 2016, 18:40

Just thinking I should make it clear that the strut failure was a symtom not a cause!
Before fingers point.

birmingham

25th May 2016, 18:57

Lonewolf_50

25th May 2016, 19:15

I am sickened to the stomach that in 2016 and 50 years since we started extracting oil in the NS, that we should still be having these all too frequent tragic losses of life.

I understand that there is an element of risk with any aircraft; after-all, there are so many things that could theoretically go bang. But my question is this: would the operators allow this frequency of failure or this level of calculated risk on a well-head or a production facility?
I am not sure how to match up the metrics of catastrophic problems per flight hour per airframe (over millions of hours) to catastrophic problems per "what unit?" per how many units per what unit of rig operation. You don't want to use dollars, and I agree with that not being a preferred metric for aviation safety. I am not sure that are comparing apples to apples.
there is an unacceptable frequency to any chopper incident in this industry, which I cannot help but feel that if such incidents were to directly impact production/revenue, they genuinely wouldn't happen ever again.
As you noted, this is why there is insurance. The cost spike from a total loss and loss of life is a non-trivial perturbation in the flow of cost over time. But that's just the dollar side. There's more to it than that, which is part of what you are getting at. I find your post well intentioned but ...

In a rotary winged aircraft, there are certain lethal "single points of failure" that are inherent in the beast. Because of their criticality, they have to be designed with a higher safety factor than a lot of other parts. (alby3z says it better in the post following this one). Major parts like the rotor mast, the swashplate, rotor blades and blade retention parts (that which holds the blade to the rotor hub) and many others. When one of these breaks under flight loads, other things break horribly. The laws of physics shall not be flaunted.

What is encouraging is that, over the years, designs more often accommodate something termed "graceful degradation." Example: if the gears start to eat each other, the systems have a way to detect those metal bits in the oil, a light goes on, and pilots have a clue that it's time to get out of the sky before it all comes apart. We've seen a few NS ditchings in the past ten years where the aircraft was lost but all souls recovered. The last 30 years of HUMS, and vibration analysis, has been a boon to catching problems early, before they become big problems. (That particular systemic improvement still has room to grow).

The core problem is that with certain dynamic components it is a binary issue:
on or off
alive or dead.
(Suggested reading topic: Mast Bumping, Bell, Huey (UH-1) 1960's or so. It was a feature of the rotor system design that was potentially lethal, but there were operational means to avoid that occurring and creating a critical failure. When you consider how many thousands of two bladed Hueys have flown, and are still flying, with the underslung semi-rigid rotor system, it is clear that lethal risks can be mitigated procedurally. The same is true for most mature helicopters: over time, the accumulated knowledge of "that'll kill you" has become known and each case has means and methods to prevent it.)

Another family of risk mitigation is in performing maintenance. A non-trivial percentage of that activity is things to check before you fly every time you take the bird up. Exam question: is the bird telling me that a key part is on the way to failure? Systems have been developed and rules crafted, and decision points laid out, to nip those in the bud and not fly the bird until any such condition is corrected. You have to go looking for them before each launch.

With the above considered: until the "why" of this accident comes to light, you can't know which of the safeguards already in place may have been missed and the holes in the Swiss began to line up.

Once the "why" is determined the system as a whole can respond. It will respond one way if it's a novel, first time failure mode, or another way if it's a previously known failure mode.
(I'll take you back to the 1960's again, and a USN A-7 that crashed on a bombing run due to a wrench being left in during maintenance, flight controls binding, and no pull up. The system response to that is still in the USN, in the form of the formal tool control program I was raised with).

Until "why" is cleared up, the "this is unacceptable" line has nothing to build on if you are looking at the whole system and all of its interrelated parts.
Accordingly, I refuse to accept that the downing of a chopper cannot be prevented. Most of the time, it is prevented. You just don't see it because the result of "it is prevented" is folks going to and from oil platforms. And while accidents do happen,
I'll be a bit nitpicky here and say that you contradicted yourself. You either accept that accidents do happen, or you refuse to accept an accident ... "the downing of a chopper"? Which is it?

Thanks for the post and its intention (from the heart).
If you believe, in your heart, that the only standard that you can accept is zero defects, I am not sure that such can be accomplished when looking at the system as a whole. It's a good target to strive for.

alby3z

25th May 2016, 19:24

To assist Birmingham,

The entire weight of the L1/L2/225 is supported on those 3 struts and their associated hardware whilst airborne.

The rear of the engines are effectively supported by the same struts, as they are bolted to the gearbox which is held in position between the top of the struts and the BBQ plate.
The rear of the engines is not a lift path.

The BBQ plate only allows for torque and is not a lift path.

I cannot imagine any scenario where a failure of a lift strut, for any reason, would allow the aircraft to continue flying.

You only have to look at the Norn Incident to see the effect of strut failure (for an identified reason)
I WAS going to say "unconnected" reason but, in fact, there is nothing in the public domain to base that on.

I think that we simply cannot imagine the forces acting on the conical housing and airframe once it all goes wrong - torque, gyroscopic, mechanical, aerodynamic, 1500 shp and 6/7 tonnes, 140 knts.

Ugh.

I am an engineer working for a helicopter OEM in the helicopter system design department.

As per FAR 29.571 any PSE (principal structural element, a failure of which would cause a catastrophic failure), must be substantiated damage tolerant or safe-life. This roughly speaking means that 1)in the damage tolerant case you must show that the element is able to withstand flight loads notwithstanding a failure of prescribed (and controlled) amplitude should occurs, 2) in the safe-life case you must show that the element subjected to loads will not have any failure in the whole operative life.

In other words the possibility to avoid any catastrophic failure is achievable also in case of failure of one component (for sure at high cost in terms of structural redundancy and weight penalty).

Hope this clarify a bit.

Kawijet

25th May 2016, 20:38

Sanus & tenfour,

Sanus wrote:
"The EC225 is cheaper than an S92. The AW189 is much cheaper than an EC225. There's little doubt that as in life the same applies to helicopters - You get what you pay for"

I think you are mistaken. The EC225 is the most expensive helicopter. Its not a case of Oil companies/operators getting the cheapest choppers to make a saving here.

industry insider

25th May 2016, 20:48

I think you are mistaken. The EC225 is the most expensive helicopter.

Price depends how many you buy. There is generally not a list price. There isn't much in it cost wise.

Kawijet

25th May 2016, 20:51

You may be correct. However, they were trying to suggest it was a Cheap and cheerful alternative which it isn't.

HLCPTR

25th May 2016, 21:48

Lonewolf - Excellent post.

roundwego

25th May 2016, 22:08

The price of S92 vs EC225 also varies depending on exchange rate. Capital cost is almost irrelevant. It's more to do with DOC as far as cost is concerned. The biggest factors are seat cost per mile and payload. Over the longer distance, the 225 seems to win hands down.

lynnx

26th May 2016, 05:40

Further to my earlier post and prompted by alby3z' comment.
In the report for the Norne crash the AIB report implies (as I read it) that it is difficult to back date safety standards in design and apply them to older aircraft.
I,m not sure how old the basic design is for the puma series, but I guess that,s why we buy NEW aircraft.
Of course, new aircraft come with new problems.

Satcomm

26th May 2016, 06:20

Come on now people, is this thread really going to be deflected side ways to talk about the cost of each aircraft. In the grand scheme of things, its operational cost vs payload. Operational cost varies from company to company and includes everything from currency, insurance, salaries to one or two ply toilet paper. Payload and payload requirements are much the same, different for every operation. At the end of the day, for someone to suggest that running a 225 is the "cheap" option and that "you get what you pay for" is well, I'm sorry, an idiotic comment. Right up there with comparing it to mountain climbing equipment!! Really??

Kawijet

26th May 2016, 06:35

Satcomm - bang on! ^^

birmingham

26th May 2016, 08:20

alby3z Thank you very useful background.

lynnx It will be interesting to see whether something to do with the (apparently) missing suspension bar assembly is a symptom or a causal factor. I think that AH's necessarily cryptic (for legal and liability reasons) early statement that the Puma's are safe to fly, led many to infer that there was an obvious primary cause (and one that differed from G-REDL). If the primary cause was that obvious and we could be assured that the risk could be mitigated by the recommended AH precautions, then I think the type would have been cleared to restart flying. The only reason I can think of, for that not being the case, is that the AIBN do not yet believe they have enough evidence to convince a shocked and fearful user base that the likely cause is sufficiently understood at this stage of the investigation. Given the frequency of recent tragedies their caution is understandable. Of course the one fact we do know for certain is that we have experienced another catastrophic structural failure. Finding the primary cause is only one part of the picture when it comes to determining how we go forward with NS helicopter shuttles.

Kawijet

26th May 2016, 10:00

I hope they continue to operate the 225. Find the issue and rectify and prevent this from happening again as far as is reasonably possible. That is the only sensible solution. I get really irritated by those "Scrap the Puma" pages on facebook. Obviously dreamt up by a knee jerk reacting Oil worker for a bunch of likes. Probably the same worker who "wont set foot on one of those death traps again!" but is at the front of the line to get on one at home time....

If they did take the decision to remove the puma from service then ALL the offshore workforce would have to work extended rota patterns to cope with the reduced number of flights... wouldn't take long for the "Re-instate the Puma!" pages to crop up. Probably from the same guy who called to scrap them.

birmingham

26th May 2016, 11:37

Kawijet

Unfortunately the numbers in the NS are stark

from when it began in 1976 - 2009 (33 years) there were 6 serious NS accidents costing 63 lives. These were the boom years of NS activity.

from 2009 - 2016 when production was starting to tail off (7 years) there were 6 serious NS accidents costing 33 lives. All Pumas

These rather unhelpful Facebook pages seek simple solutions e.g. If you ban all Puma flights you will reduce Puma death rates by 100% - Can't argue with that but I wouldn't describe as a considered solution to prevent NS helicopter accidents!

Anyone who knows anything about aviation knows this tragic run affecting the Puma could have happened in other types. MGB issues are hardly unique to Pumas and the Pumas's maintenance, operations and many components are often supplied by the same companies as AW, Sikorsky, Bell etc.

However there is a general attitude among today's NS people that everything should get safer - much safer.

Any aspect of the business which is as potentially risky today as in 1976 has a massive problem.

industry insider

26th May 2016, 12:25

Now anyone who knows anything at all about the aviation business knows that this unfortunate tragic run that has affected the Puma could have happened in other types. MGB issues are hardly unique to Pumas and the Pumas's maintenance, operations and many components are often supplied by the same companies as AW, Sikorsky, Bell etc.

Really? Apart from engines, I can't think of any other critical dynamic components which are supplied as you describe.

jerrycan

26th May 2016, 12:26

I am one of your passengers in the NS, SLF I have heard us referred to, and I'm quite angry about the petitions on Facebook to have the 225 banned. It is IMO an overreaction and based purely on emotion.
I want to see the 225 returned to action asap, the statistics tell me that it is far safer to fly offshore in a 225 than it is to ride my motorcycle when I'm home on leave.
For me the bottom line is if the 2 guys up front are happy to fly the aircraft day in day out then I will get on it.

Just wanted to say!!!

gasax

26th May 2016, 12:28

I work in technical risk assessment for the offshore industry. When you calculate the risk which the workforce are exposed to, helicopter flying is a significant element. It depends upon the age, layout and complexity of the installation but on a modern platform the transport risk is typically 30 to 40% of the total risk.

Given the workforce have no say in the matter, or influence over it, makes them a hostage to fortune. The oil and gas industry used to boast that helicopter flying was getting safer - and they were right - until recent years, when the accident rate went back up. The oil and gas companies have tried to engage with the workforce to convince them helicopters are safe but been defeated by the accident rate!

Pilots tend to concentrate on the major component failures, but the workforce do not differentiate - pilots flying perfectly serviceable aircraft into the sea has not helped the workforces' perceptions.

When they pay to fly it is fixed wing (virtually always) and typically about 100 times safer than flying in a helicopter. Which sort of sets the scene. Whilst technically helicopters can never be as safe as fixed wing, the helicopter companies and the CAA have been pretty complacent over a non-improving accident rate. CAP 1145 was very much a reflex, certainly not a measured approach.

The longer offshore rotas (3 on, 3 off for instance) will actually change the balance of risks more toward those on the platforms than the flight risks. But it is a comparatively small community and few offshore workers do not know someone who has not been involved in at least a helicopter incident, if not an actual death. I've been in the industry for quite a while and two people I have known have died in offshore helicopters - both onboard the Chinook.

Would you buy a ticket with Malaysia Airways or Egypt Air, if you had the choice of a company with a Western European accident rate for the same money?

jerrycan

26th May 2016, 12:37

I'm one of the passengers in the NS and have been on and off since 1983, I don't known anybody that has been involved in a helicopter incident.
I am also quite angry by the stuff that appears on Facebook, my nearest and dearest sometimes read stuff on there and I don't want them thinking I'm going to work traveling in a "deathtrap".
I want the 225 to be put back in action asap, for me the risks going to work in a 225 is probably minuscule compared to riding my motorcycle when I'm on leave!!
The bottom line is if the 2 guys up front are happy to fly a 225 day in day out them I'm happy to go with them.
Just saying!

birmingham

26th May 2016, 12:38

Industry Insider

Maybe, but don't think that changes the sentiment of the post - let's say operations, maintenance, engines, parts etc. My point was that the other types could also have a run of fatal accidents.

Miles Gustaph

26th May 2016, 12:44

Gasax, I'm sorry but "Given the workforce have no say in the matter, or influence over it, makes them a hostage to fortune." is an overly dramatic, non-poetic way to say "in it for the money."
Anyone who works offshore can re-locate to the beach anytime they want to, there are no hostages real or perceived, it's a personal choice, with choices.

And as for "the helicopter companies and the CAA have been pretty complacent over a non-improving accident rate." In your role as a Technical Risk Assessor for the offshore industry how have you reflected this? Or have you skirted over this to keep your employer happy and look after your own interests? I'm sure there are plenty of people on this thread happy to discuss the impact of Energy companies, and their 'experts', their requests for rate reductions? Their own individual requirements as apposed to the OGP or other industry requirements to be 'special', the impact of their flight programme with the single aim of keeping the offshore workforce happy and not the best human factors approach, and there are many more... So having identified yourself as a technical risk assessment professional what have YOU done to work with your company to make things safer? ...or is it someone else's problem, OEM's, Operators etc?

alby3z

26th May 2016, 12:52

212man

26th May 2016, 12:55

gasax

26th May 2016, 13:58

Miles - I would certainly take your point about there being a choice. However when that choice turns out to be rather different than portrayed people are not unnaturally unhappy. Refusing to fly means near instant unemployment - something you are keen to experience?

As for what have I personally done? In most cases my efforts have been directly refuted by the helicopter companies - 'flying at night is no more dangerous than during the day', 'no it is not a CAP 437 helldeck but why would it be any more dangerous?' from just two items of work recently.

My ultimate clients, the oil companies generally accept the numbers but are immovable in terms of changes to contract conditions. ALARP is a great principle but they are completely resistant to anything which is not direct regulatory compliance. Given the majority are headquarter in the US this is not surprising. In the US the legal profession clear things up afterwards..... and the companies are content with that - hence lonewolf's comments above.

To 212 I would say be careful which data you use and how you compare it. Using Global figures neatly reduces all the differences. The IOGP figures for the N.Sea utilise a period when accidents rates were at a historic low - very useful for generating low risk numbers, they are now back up where they were before the middle to late 1990s. So inspite of new design aircraft, the accident rate has gone up. If you utilise the CAA figures in CAP1145 and 1036 you see a difference in 25 to 30 in fatal accident rates - but again smeared by the use of 5 year moving averages. Remove that and you get to around 80 - hence my glib use of the number 100.

But the real point is that there should be no reason that helicopter travel should not be at least as safe as it was for the period covered by the IOGP data. CAP1145 concentrated very much on the right hand side of the BowTie - catering with 'after the crash' measures. That is not the right approach.

Miles Gustaph

26th May 2016, 14:59

Gasax,

I'm sorry but the reality of the North Sea is that while we all work diligently towards a zero accident rate, history and the environment shows us that despite performance and technological improvements accidents still affect the workforce.

This is absolutely heart-breaking but it is a reality that has existed, abet with different probability / severity levels since the first single engine helicopter went offshore.

Anyone who goes offshore knows this and the reality is that they are struggling with their own personal risk appetite and willingness to take a job with perhaps a lesser salary and certainly less time-off. Safety has improved as has the salaries and time off for the workforce which is the true root cause of workforce unhappiness. That said it is absolutely an imperative that the industry as a whole does everything it can to continually improve safety performance.

As for your examples of what you have done. You have given very poor examples and I am astounded that a technical safety assessor makes claims that can be so easily refuted. Did you provide data or did you rely on you technical skill, or was it just common sense that makes to think your being bull****ted by aviation professionals? If this is the level of your skillset and a representation of your work then I am not surprised that the workforce has unrealistic expectations of performance and are unhappy as you are making the unrealistic expectation to them, not the aviation companies!

Magjam

26th May 2016, 20:15

There seems to be some misunderstanding on certain factual details regarding the accident discussed in this thread. I will quote and link relevant sources so that we can all try to have a better understanding of the matter at hand.

They have only recovered a very small piece of the front suspension bar. ( plus the upper attaching pin, bearing and nappy pin). I don't see how AH can decide this early that the 225 is totally safe to fly. If they do not have the lower 90% of this Rod and the lower attaching bracket plus it's pin then there is a huge piece of the puzzle missing. What if they find these pieces later and there is evidence of metal fatigue or other failure. It seems to me they are mainly concerned if it is a gearbox problem like previous events. So far they feel it is not and therefore business as usual.

The latest from the AIBN is "most of the wreckage is recovered" - hopefully including the missing lift/suspension bar and associated components. It will be interesting to see whether something to do with the (apparently) missing suspension bar assembly is a symptom or a causal factor.

During the press conference that the AIBN held on the 13th of May the following was stated:

"We've noticed certain images in the media of a suspension bar - a "lift connection" - where a "foot" is missing. We've seen that this have created certain rumors.. The reality of the matter is that we have all the components belonging to the suspension bars. We have a good grasp on how the mechanisms there function, so far, but still a lot of research remains to be done also on that matter. However all components, as we see it, have been present. Though we are still missing the center portion of one of them, we do have the end pieces."

A follow up question from a journalist:

"When you said that you had found all the components belonging to the "torsion bars" (I assume he was referencing the suspension bars)", does that mean you have found all bolts, all safety connections etc. from which one could say no bolts have snapped, is that correct?"

Answer:

"We do not have all the bolts from the fixings. But we have traces at the fixings, both at the "base mounts" and on the... and we also have some bolts."

They also go on to later say:

"Half of all epicyclic gears have been found, approximately 50% of each of the two stages."

And:

"What is important to us at this point is to find the second stage planet carrier."

SOURCE (http://www.aftenposten.no/webtv/?video=4184092#!/video/111679/havarikommisjonen-holder-pressekonferanse-etter-helikopterulykken)

The video of the conference starts at 15:29 and the above quotes starts at at 19:18 (Norwegian only).

lynnx

26th May 2016, 20:37

birmingham

26th May 2016, 20:41

Magjam,

That is very helpful. I don't have enough Norwegian to follow the broadcast and there has been very little detailed English language reporting of it as far as I have seen.

charlieDontSurf

26th May 2016, 23:41

Any thoughts about all the pitchlinks been severed on the middle?
Could that be an indication of sudden stoppage of the MGB?
Can't remember anyone commenting those.

OnePerRev

27th May 2016, 01:51

Reviewing the 1997 LN-OMP Puma mishap report:

In that case the forward support bar fractured, and the head pulled the gearbox up and back, ripping off the transmission support frame and both rear struts. Gearbox and head all stayed together, despite tremendous rotor forces.
Also in that case, then Eurocopter, the OEM, seemed to come up with rebuttal to root cause, and the report refers to their claim as "absurd".

This is a chicken and egg situation as far as gearbox destruction or strut separation. There are two precedent mishaps with known and different causes, with different outcomes.

We should and do expect that despite the press release strategy, AH will be keen to investigate root cause and work diligently to effect the solution.

buzz66

27th May 2016, 02:23

birmingham

27th May 2016, 07:45

Buzz66 agreed.

The current oil price is relevant here. At $50 and sub $50 oil much of the world's oilfields and a great deal of the NS fields are marginal at best. So we can't look at the current situation as business as usual.

Contractors are distressed and handing back aircraft. CHC alone are planning to let go of 38 332s and 225s in the next 90 days and will have 16 spare S92s that are going the same way.

Statoil are starting their own investigation into this incident and part of its remit is to recommend to the CEO and COO how they will respond to the tragedy to improve safety.It is inevitable that this enquiry will review the Puma's safety history. One option among many (and I stress option) is to switch types.

I'm not advocating this option - my personal view is that the problem (and please accept we have a problem here) is not with the Puma, in particular, but helicopter safety in general. That despite much improvement in the technology and continuous effort, we have been unable to improve the NS safety record for helicopters which (for fatal accidents at least) sits stubbornly at 1970s levels.

Also and to spare anyone pointing it out I am fully aware that changing types will not, in itself, in anyway whatsoever, guarantee an improvement in safety, it might even reduce it! - but it is an option that all the customers will probably consider.

lynnx

27th May 2016, 08:02

Charlie,
I suggest that the pitch change rods are broken because they represent the weakest link in the chain of main rotor head, rods, swashplate, and servo to gearbox attachment points once the head itself has detached.

alby3z

27th May 2016, 08:44

Any thoughts about all the pitchlinks been severed on the middle?
Could that be an indication of sudden stoppage of the MGB?
Can't remember anyone commenting those.

CharlieDontSurf that's not possible, because the pitch links rotates with the rotor head, a sudden stop of its rotation would not cause damage at all to these elements.

Magjam

27th May 2016, 10:50

Correct me if I,m wrong, but reading those quotes......at no point was it said that anything was installed correctly/not installed correctly or had, for certain items, even been found!
Carefull weasel words, and no wonder rumours abound.
I do , however, absolutely understand the reason for them.

Weasel words? Really?

You are right in that nothing was stated about any parts being installed incorrectly.

I believe the point of this press conference was to give a short statement, present some more or less random parts recovered and to answer questions about the preliminary report released on the same day.
The point of it was not to give out any hasty speculations or conclusions as to causal or contributing factors. If anything, any hesitance or re-phrasing during the statements seems to be to avoid doing just that and to avoid delving too deeply into technical details (which they actually stated later on when a journalist asks what a "base mount" is). To me it seems they were offering as much transparency that could be expected at the time.

As to if: "..any certain items had even been found!", you have to be a bit less bombastic and a bit more specific than that. I recommend that you watch the video or read the quotes again where it was stated:

"The reality of the matter is that we have all the components belonging to the suspension bars."

And:

"Though we are still missing the center portion of one of them, we do have the end pieces."

I believe the rumor they alluded to was one where either the fitting (aka fixing/foot/base mount), the mounting bolt, the safety nappy pin or all of them had not even been installed on the lower part of the forward suspension bar and were sitting on a table in a hangar somewhere.

They debunked that rumor, at least as far as I am concernced.

lynnx

27th May 2016, 12:59

Jdbelo

27th May 2016, 13:25

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The Helicopter Accident: Information to the public about components found in the area 27.05.2016

A Super Puma helicopter enroute for Bergen, crashed on Store Skitholmen near Turøy in Hordaland 29 April 2016. The Accident Investigation Board of Norway (AIBN) like to inform the public about the following:

Any components found, that can be traced to the helicopter accident, should immediately be rinsed with fresh water and applied a conserving oil. Contact the Police, phone: 02800. Findings may be submitted to Sotra and Øygarden police, phone: 56 31 58 00, or to Bergen police, phone: 55 55 63 00.

If a discovery is made of wreckage components that partly or completely match with pictures attached, please take direct contact with AIBN, Aviation department, at 24 h. telephone for notification: 63 89 63 20.

Stag

byeskille

27th May 2016, 13:47

AIBN has this afternoon published a press release with info to the public on how to handle finds of missing parts.
| AIBN press release (in Norwegian) (http://www.aibn.no/Om-oss/Nyhetsarkiv/Helikopterulykken-Informasjon-til-publikum-om-eventuelle-funn-i-omradet)

They tell the public to rinse finds with fresh water and call the local police.

They also attached three photos of special missing parts, and tell the public to call the AIBN immidiatly if they are found.

Here are the photos:
http://www.aibn.no/Om-oss/Nyhetsarkiv/Helikopterulykken-Informasjon-til-publikum-om-eventuelle-funn-i-omradet?iid=19822&pid=SHT-Document-Attachments.Native-InnerFile-File&r_n_d=52182_&adjust=1&x=300&from=0 (http://www.aibn.no/Om-oss/Nyhetsarkiv/Helikopterulykken-Informasjon-til-publikum-om-eventuelle-funn-i-omradet?iid=19822&pid=SHT-Document-Attachments.Native-InnerFile-File&r_n_d=52182_&attach=1)

http://www.aibn.no/Om-oss/Nyhetsarkiv/Helikopterulykken-Informasjon-til-publikum-om-eventuelle-funn-i-omradet?iid=19821&pid=SHT-Document-Attachments.Native-InnerFile-File&r_n_d=52182_&adjust=1&x=300&from=0 (http://www.aibn.no/Om-oss/Nyhetsarkiv/Helikopterulykken-Informasjon-til-publikum-om-eventuelle-funn-i-omradet?iid=19821&pid=SHT-Document-Attachments.Native-InnerFile-File&r_n_d=52182_&attach=1)

http://www.aibn.no/Om-oss/Nyhetsarkiv/Helikopterulykken-Informasjon-til-publikum-om-eventuelle-funn-i-omradet?iid=19820&pid=SHT-Document-Attachments.Native-InnerFile-File&r_n_d=52182_&adjust=1&x=300&from=0 (http://www.aibn.no/Om-oss/Nyhetsarkiv/Helikopterulykken-Informasjon-til-publikum-om-eventuelle-funn-i-omradet?iid=19820&pid=SHT-Document-Attachments.Native-InnerFile-File&r_n_d=52182_&attach=1)

Magjam

27th May 2016, 14:58

Question;

"When you said that you had found all the components belonging to the "torsion bars" (I assume he was referencing the suspension bars)", does that mean you have found all bolts, all safety connections etc. from which one could say no bolts have snapped, is that correct?"

Answer;

"We do not have all the bolts from the fixings. But we have traces at the fixings, both at the "base mounts" and on the... and we also have some bolts."

Is this not specific enough? ( and not included in your post)

A lot of this comes down to interpretation and translation, but I sincerely believe that the bolts he is referring to are the ones attaching the 3 fittings to the roof-structure of the aircraft. 4 bolts on each fitting, so a total of 12. It is obvious to me that some of them are missing, since I imagine they have sheared/pulled right off at or after commencement of the catastrophic event or at ground impact.

The traces he speaks about which makes them believe all these parts were present at the start of the accident, I assume are on the fittings (which they claim to have) and the roof structure itself. Whether or not these bolts had been correctly torqued is pure speculation at this point.

I don't know if this has been posted here earlier, but I found an eyewitness interview recorded on the day of the accident. The person works offshore but was at home outside his house on Turøy island, about 1km slant range from the helicopter ToD (my google map estimate) looking at it with his daughter. He says he has helicopter flights passing by his house every day and he rides them to and from work.

Source (http://www.nrk.no/hordaland/oyenvitne_-_-jeg-sa-at-rotoren-falt-av-_-deretter-gikk-helikopteret-i-bakken-1.12924223)(Norwegian only)

The translation:

"I was looking at the helicopter as it was flying normally. Then after a few seconds it started veering back and forth quite substantially followed by 3-4 quite loud bangs where we then clearly see parts coming off of the helicopter. A few seconds after that there is one additional bang after which the helicopter goes straight down and the rotor has come off."

He estimates a time period of 10s maximum between the veering and the fuselage crash/impact with the ground. As he saw the rotor seperate they ran inside the house as he thought the rotor could possibly come crashing down on them.

birmingham

27th May 2016, 15:16

Magjam

27th May 2016, 15:37

Birmingham

If you re-read my initial post with the quotes, you will see the following stated by the AIBN on the 13th during the press conference:

"The reality of the matter is that we have all the components belonging to the suspension bars."

"Though we are still missing the center portion of one of them, we do have the end pieces."

"What is important to us at this point is to find the second stage planet carrier."

Furthermore, in the AIBN press release today, even though they posted a photo of the already recovered 1st stage planetary carrier, and a non-connected suspension bar it was only added for comparison to help the public in their search to find the still missing 2nd stage planetary carrier as well as the mid-portion of the FWD suspension bar. It says so in Norwegian in the text above the photos, and the statement in the post from Byeskille saying "..three photos of special missing parts.." is incorrect. It states no such thing in the press release.

In fact, here is the whole official statement about the photos on the AIBN webpage, in English (http://www.aibn.no/About-us/Nyhetsarkiv/The-Helicopter-Accident-Information-to-the-public-about-components-found-in-the-area).

There is now also an updated preliminary report available, released today.

Link (http://www.aibn.no/Aviation/Investigations/16-286)(English)

Satcomm

27th May 2016, 15:44

Birmingham, from the quotes above.

However all components, as we see it, have been present. Though we are still missing the center portion of one of them, we do have the end pieces."

I read, they have both ends of one of the suspension bars (front one, as the pics show the other 2) but they are still missing the middle section (the tube section).

Satcomm

27th May 2016, 15:59

Chance it, so much for that theory.

3 cases of rotor head detachment in 9000000 hours flying , 2 of which were MGB epicyclic planet gear 2nd stage bearing's , However the MGB was trying to give warning by making metal for a couple of weeks beforehand that were ( for different reasons) unfortunately misdiagnosed and 1 where we don't quite know yet , but we do know that there was no issue with CWP / Marms beforehand and an intact epicyclic ring gear in the wreckage , so nothing like the 2 earlier accidents, yet all this hysteria .....!

The latest update pretty much confirms it for me. Obviously, just my own opinion, but really does seem to be a similar event to G-REDL.

birmingham

27th May 2016, 16:07

that explains it thanks - I wish I had carried on with my Norwegian!

birmingham

27th May 2016, 16:36

the new report update is helpful (and in English) it says as Satcomm points out ...

Whilst several parts vital for the investigation have been recovered the four weeks since the
accident, some key components are still missing. These components are in particular the epicyclical
second stage planet gear carrier and parts of the forward suspension bar.

and interestingly ...

The investigation team has discussed a list of scenarios that Airbus Helicopter prepared based on
fault tree analysis. At this stage, the AIBN can confirm that the scenarios under consideration
include failure of epicyclic module, suspension bar (lift strut) attachment and MGB conical
housing

AW009

28th May 2016, 00:35

Not each PPRuNe-User is a pilot and/or engineer being conversant with (Super) Puma. Two video clips for a better understanding of the problematic: https://www.youtube.com/watch?v=UnpvtFQowKc & https://www.youtube.com/watch?v=oD4jKBOIBwc

BTW: The gearbox manufacturer and AIRBUS supplier for AS 330 - according to PPT https://www.yumpu.com/en/document/view/46825679/meeting-component-reliability-demands-of-the-aerospace-industry-/7 , page 6 page 7 and to https://www.avioaero.com/Press-releases/Airbus-Helicopters-and-AVIO-AERO-sign-agreement-for-technologically-advanced-helicopter-accessory-gearboxes - is the AVIO PROPULSIONE AEROSPAZIALE SPA, which is also the developer and manufacturer of the Propeller Gear Boxes of A400M.

(https://www.youtube.com/watch?v=oD4jKBOIBwc)

Condor99

28th May 2016, 01:15

@birmingham (http://www.pprune.org/members/194930-birmingham): you wrote: "the new report update is helpful (and in English) it says as Satcomm points out ..."

Really ? In what ?
Explain !

birmingham

28th May 2016, 10:28

@birmingham (http://www.pprune.org/members/194930-birmingham): you wrote: "the new report update is helpful (and in English) it says as Satcomm points out ..."

Really ? In what ?
Explain !

It confirms the evidence so farsuggests the problem initiated either in the suspension bar assembly or gearbox and they are looking for more parts to confirm which. They are also investigating the conical housing.

Hence why on day two AH told ops to check items associated with these failures modes but seemed to suggest based on the presentation of the wreckage they thought suspension bar theory more likely. They couldn't say so for many reasons; not least that like AIBN they couldn't be certain.

So we now know they haven't yet recovered enough debris to do more than hypothesise about the cause.

Currently we don't know for certain what happened let alone why.

So AIBN have been honest and open and said they are still searching.

So it is helpful in that it is absolutely clear where they are and what they are doing and also why that is all they can say at each stage.

AW009

28th May 2016, 11:56

@Mitchaa, @Birmingham:
According to Airbus Helicopters’ analysis, seven potential initial events have been retained to explain the main rotor detachment of LN-OJF. Out of these seven scenarios, only one – the failure of the attachment of a suspension bar – can been assessed as probable by Airbus Helicopters, based on the information available to date.
At this stage, the exact cause of this possible event is still unknown. Analysis of the helicopter’s maintenance history has just started and should provide a better understanding of the most likely causes.
Source: Norway-Statement - Airbus Helicopters (http://www.airbushelicopters.com/website/en/ref/Norway-Statement_347.html)
Certainly this is not a wise and diplomatic statement by AIRBUS.

The Accident Investigation Board Norway, or AIBN, said failure of the housing of the main gearbox, a gear called the epicyclic module and a suspension bar that attaches the rotor to the airframe are being considered as possible causes for the April 29 crash.
Source: Correction to Norwegian Helicopter Crash Investigation Story - NASDAQ.com (http://www.nasdaq.com/article/correction-to-norwegian-helicopter-crash-investigation-story-20160527-00487) So AIBN avoids in present and still unsufficant body of evidence any anticipated verdict on sb./sth. and this evenhandedness is most expedient.

birmingham

28th May 2016, 12:03

@Mitchaa, @Birmingham:

Certainly this is not a wise and diplomatic statement by AIRBUS.

I guess they feel they need to raise the profile of this. So much so that the CEO has put his career on the line in approving the release of the latest statement. They must be supremely confident that this will be the final conclusion of the AIBN.

helicrazi

28th May 2016, 12:34

Airbus are firmly pointing the finger of blame in one very clear direction with that statement, just like they have been from the start.

AW009

28th May 2016, 12:42

Can a (Super) PUMA insiders say definitively whether Avio is still involved in the development and manufacture of current MRGB, or is the basic concept of the present MRGB only a legacy from the days of the AS 330 and Airbus alone would pass the buck, if the Statement of AIRBUS would proof as inaccurate?

buzz66

28th May 2016, 13:51

Arrrgggg finally a few more pictures of the puzzle.

The Missing Ring Gear makes it's presence now....That my friends now makes this whole thing a game changer.

Anyone notice Airbus put the Sus Bar as lead cause, but the AIBN have Epicyclic as lead cause.

Airbus know dam well an Epicyclic failure is an absolute game over scenario for the EC225. It might be allowed to live if the Sus Bar or Foot was proven as root cause.

Like I said in the beginning a Sus bar failure won't result in a ruptured gearbox.
EVERYTHING including the Engines literally hangs off this Gearbox and will break away with very little resistance.
It's simple physics.
Any massive sudden over torque will cause a Bevel Gear to fail well before a Straight Cut Gear. The only reason they use Bevel Gears is because Straight cut Gears can't transmit TQ 90 Degree's. Any TQ failure induced by the way of a failing Sus Bar will destroy the Bevel well before the Epicyclic lets go.
This didn't happen here.

Here's another thing, during run dry full power testing the Gearbox finally grinds to a halt after it twists the engines off like butter, Barby Plate tears away the Sus Bars then snap like twigs and guess what, the Gearbox stays in one piece. Funny that hey!

So somehow this Sus Bar defied the Laws of Physics by breaking and either it, or one of it's 2 ...Tin Can Mates then damaged the Gearbox Case (Bit like throwing an empty Beer Can at your Car and expecting the Window to be broken), by now there is no TQ going into the gearbox because those 3 piss ant Tie Bolts holding the Engines to the Tranny are the first thing to leave the scene, and then the Ring Gear bursts with enough force to spit Planets out that end up in different locations despite no TQ coming from the Engines.....Nice Fairy Tale. I wish you all the Best with that Mister Airbus!
Talk about failing on your Sword.

Simple fact is s Broken Sus Bar or foot will transfer lifting force from the Sus Bars into the Barby Plate and the whole Tranny, less the Engines would depart the Scene.
It's really no more complex than that.

It's about time Helicopter design stopped trying to mimic the Fixed Wing World, and concentrate on reliability and longevity instead of efficiency.
Keep in mind a Helicopter is a very inefficient (https://www.google.com.au/search?biw=1366&bih=604&q=inefficient&spell=1&sa=X&ved=0ahUKEwiRjJyNhf3MAhWJopQKHbaoDyEQvwUIGCgA) and inherently unstable platform to begin with, and trying to change that comes at a cost.
I know what the cost is and who ends up paying for it....Question is do you!

I knew in my gut the EC225 was never going to make it the first time I stood under the Rotor when it was running some 7 years ago now.
I still maintain and always will, that weird kidney pounding harmonic thump these 225's produce with FPOG is just not normal for anything that rotates let alone a Helicopter.

Satcomm

28th May 2016, 14:16

Buzz66 - my thoughts as well. That's exactly why I have not bought into the suspension bar theory from the beginning. I think we would have seen a pic of the whole assembly MGB and MRH being slung away.

buzz66

28th May 2016, 15:50

Any thoughts about all the pitchlinks been severed on the middle?
Could that be an indication of sudden stoppage of the MGB?
Can't remember anyone commenting those.
That would have occurred when the MR finally came in contact with Terra Firma.

AW009

28th May 2016, 19:20

May I remind my question in comment http://www.pprune.org/9391153-post971.html politely? The answer may be of the highest economic policy and in particular armor political importance.

birmingham

28th May 2016, 20:31

That is quite an incredible statement made by Airbus.

I'm actually in shock that they would undermine the official accident investigation with their own theory and share that with the world.

Certainly very unusual see this article from Reuters http://news.trust.org/item/20160528144905-i8qy5

AW009

29th May 2016, 00:38

@Mitchaa, @Birmingham & @satcomm: To pinpoint on something or on somebody, in the particular case AIRBUS Helicopters has the least privilege because the 'suspension bars' are also an extremely questionable construction!

Aussierob

29th May 2016, 00:54

AW009

29th May 2016, 01:08

@Aussierob: Redundancy (technical mechanics), resonance (harmonic oscillations, interferences, stimulations of vibrations), realiability (bolts, washers & nappy pins), please see my comments before. E.g. http://www.pprune.org/9372108-post612.html
or what do you think about the 3-leg-theory and its redundancy? As well as a 4-rotorblade-system should have 4 suspension bars and a 5-rotorblade-system should have 5 suspension bars and those should be symmetrical? Ask some pilots which are also engineers.
(http://www.pprune.org/9372108-post612.html)

letmein

29th May 2016, 06:02

Buzz66:
Like I said in the beginning a Sus bar failure won't result in a ruptured gearbox.
[..]It's simple physics.

Simple physics?!..Buzz, you made me laugh a little today..thanks.

Let's face it...Airbus knows exactly what happened. They've known all along... and by now they've backed up their theory with real physics. (finite element analysis)

The AIBN will need to address the root cause soon..and it's tough.. this catastrophe was caused by a "maintenance event(s)".

Nadar

29th May 2016, 07:13

Let's face it...Airbus knows exactly what happened. They've known all along... and by now they've backed up their theory with real physics. (finite element analysis)
You seem awfully sure that anything AH is saying is true. Personally I don't trust anything that comes from commercial sources, they always have an agenda other than the truth. Unless I've missed something, they haven't backed up anything, they've just made their claim more clear. They haven't described the other 6 "possible scenarios" and why they were so unlikely. I think it's very hard to have any confidence in claims without any description of the thought process behind it.

The AIBN will need to address the root cause soon..and it's tough.. this catastrophe was caused by a "maintenance event(s)".

The last time I checked AIBN doesn't have to come up with anything - they will take the time needed to figure it out and then present the final report. That's the beauty of (commercially) independent bodies/entities.

DOUBLE BOGEY

29th May 2016, 07:14

If suspension bar fails, for whatever reason, and the head flaps dramatically, this would put huge strain on the conical housing. If the conical housing ruptures, and in this case it has, the mast splined end in the upper stage epicyclic would impact a huge lateral bending loads on the planet carrier which in turn would compress the gear train and put huge lateral loads on the ring gear in the moments before catastrophic failure of the whole assembly.

There are many ways to de-construct the scenario. I think we should keep an open mind.

letmein

29th May 2016, 07:46

Nadar>> Personally I don't trust anything that comes from commercial sources.

You wouldn't trust the RFM (Flight Manual) that is issued by Airbus Helicopter?
More Generally, you don't trust cars, planes, restaurants, soap, toothpaste??

Nadar>>The last time I checked AIBN doesn't have to come up with anything
But then you go on to say that they have to present the final report.. So which is it??

Hompy

29th May 2016, 08:17

What I find distressing about all crash threads is the almost desperate attempts of some contributors to apportion blame. In this case the person/people who posted "blaa blaa 'firewall' blaa blaa 'hangar floor'" etc. That specific post has been removed or taken down which is good, but there has been a common theme since that post which I find depressing at best.

Airbus have followed a similar nudge wink marketing/mitigation line since about day two. They couldn't possibly have 'known all along' what was the cause of this accident or there wouldn't be three or four possible causes now. All we can say for sure is that something above the cabin roof detatched from where it should normally be or broke and the aircraft fell to earth.

I would like to know what happened in this case. I am sure the families of those involved are desperate to find it out.

However, it is important to realise who in this or any crash has a vested interest in a particular outcome. The operators have an interest. One operator would like it to be the fault of the manufacturer and all the others would like it to be a maintenance error. The manufacturer also want a maintenance error to be found as the cause.

I have heard it said that the AIBN are biased. I don't believe this and were it true would the CAA or AAIB or BEA or any other party involved let that pass? Absolutely not.

So, the only unbiased view will be that of the investigation board.

With this in mind, some posters should have a little sensitivity towards the people directly involved, the engineers specifically. Fine to hypothesize, just as long as what you are saying doesn't point the all to easy to point finger at one or two individuals. It is wrong to do so and those doing it either lack the intelligence to realise it or are deeply unpleasant. That is me pointing the finger at you, you know who you are! :=

birmingham

29th May 2016, 09:10

Letmein,

Do you work for Airbus or are you reliant on the H225 keeping you in a job? Is your judgement being clouded by hope? Hope to save the H225?

That's exactly what Airbus's recent statement sounds like to me.

I wonder if Airbus can recreate their theory in a test bed environment and prove that a forward suspension bar attachment foot failure would cause an instantaneous failure of the head?

Who was at fault when G-CHCN ditched in the North Sea 5 months after G-REDW did for the exact same reason? This was followed by a 9 month suspension of EC225 flight. Eurocopter at that time did not protect its fleet (otherwise the 2nd failure would never have happened)

Questions how they handled the G-REDL incident.

I too would rubbish anything that the manufacturer claims at this point. What were they hoping to achieve with their statement? 225's to resume flying Monday and all to be forgotten about?

Let's wait on an independent AIBN report to conclude their findings.

Folks,

It always makes me smile when people say we should wait for the final report. Why? it is perfectly reasonable to discuss what happened. What we should do is avoid wild speculation and recognise that the various parties are subject to constraints we are not. Please also remember that the people at AH, CHC, AAIB etc. are professionals and while they have slightly different agendas in my opinion and experience are certainly not dishonest.

I think the reason AH have started to push what they see as the probable cause is that the 225 programme won't survive another 9 month suspension. This is nothing to do with the cause of the accident (although they clearly believe that is associated with the failure of the transmission shaft suspension). It is to do with the fact that NS is in decline, the oil price is low, the helicopter business is surviving on military orders, the operators are in financial distress and machines are being returned to lessors at an unprecedented rate. Lessors may see this as an oppopportunity to restructure their civil heicopter portfolios while their fixed wing business is boyant.

Thus the Pumas may end up effectively withdrawn well before the AIBN issues its final report and whatever that concludes.

Magjam

29th May 2016, 10:25

Well said Hompy, I agree wholeheartedly.

Birmingham, I think the emphasis here is on the word "conclude". Hypothesizing and discussing is in my opinion fair game at this point, but to conclude and point fingers is not.

As the investigators initally responded to the press about AH statements: "There are still many doors open, we will close them one by one."

G0ULI

29th May 2016, 10:26

Airbus Helicopters issued a statement after a relatively brief examination of only the partially recovered wreckage to the effect that their product was not at fault. The Norwegian air accident investigation team have since recovered more wreckage and have had the opportunity to examine it in detail, yet they have made no comment as to the precise cause.

In order to be able to make such a statement Airbus Helicopters either had immediate access to information that is not in the public domain, or, that this was a known problem that they knew could happen but on the balance of probabilities they thought unlikely.

From the victim's (and their families) point of view, it is immaterial if the gearbox split and severed a suspension bar or the suspension bar failed causing the gearbox to rupture. The end result was the main rotor separating from the aircraft and that is an unacceptable design flaw in any rotor craft.

It is immaterial if analysis shows that such failures can be expected only once in 100 million hours of operating. It has happened on at least three occasions in helicopters of similar design to date. The problem with probability is that supposedly rare events can happen in close clusters and when that happens the psychological impact is such as to overcome the rational thought process. People are disinclined to trust their life to such a machine, even though it can be demonstrated that such failures are extremely unlikely.

NASA had an enviable safety record when allowed a virtually unlimited budget, but engineering compromises and cost cutting measures eventually resulted in the loss of two space shuttles. Have commercial pressures reduced Airbus Helicopters to a similar situation where a known design weakness has been ignored because it was cheaper to budget/insure against a crash or two rather than fix the root cause?

Oldlae

29th May 2016, 11:09

Back in the day, the 332L suspension bars were lifed, inspected every 750 hrs and X-Rayed every 12 yrs. I do not understand why there are, apparently, two failures of a bar leaving a centre portion missing. If the bar failed at the top, the bottom part would, presumably, remain with the fuselage. If it failed at the bottom the upper part would stay with the MRH. I do not know how the bars are constructed, can someone advise on this?
It is possible the the Main Rotor Shaft damaged the MGB parts when the MRH and blades departed.

AW009

29th May 2016, 12:02

Oldlae: I do not know how the bars are constructed, can someone advise on this?
Have’nt you seen all those fotos, pictures and graphics of suspension bars, MRGB and MR-Head uploaded in present thread? (https://www.yumpu.com/xx/document/view/55598569/suspension-bar-h225)

buzz66

29th May 2016, 12:04

Buzz66:

Simple physics?!..Buzz, you made me laugh a little today..thanks.

Let's face it...Airbus knows exactly what happened. They've known all along... and by now they've backed up their theory with real physics. (finite element analysis)

The AIBN will need to address the root cause soon..and it's tough.. this catastrophe was caused by a "maintenance event(s)".
Wow Buddy you sound really terrified.
It was my never my intent to distress you or any Punters on this forum.
This is not my first time to display the blunt facts as I see them.
I know it comes home hard with some people. I feel your pain Buddy it's ok to let go!

The more things go off track the louder I get.
Some people want me louder others not.

buzz66

29th May 2016, 12:15

Folks,

It always makes me smile when people say we should wait for the final report. Why? it is perfectly reasonable to discuss what happened. What we should do is avoid wild speculation and recognise that the various parties are subject to constraints we are not. Please also remember that the people at AH, CHC, AAIB etc. are professionals and while they have slightly different agendas in my opinion and experience are certainly not dishonest.

I think the reason AH have started to push what they see as the probable cause is that the 225 programme won't survive another 9 month suspension. This is nothing to do with the cause of the accident (although they clearly believe that is associated with the failure of the transmission shaft suspension). It is to do with the fact that NS is in decline, the oil price is low, the helicopter business is surviving on military orders, the operators are in financial distress and machines are being returned to lessors at an unprecedented rate. Lessors may see this as an oppopportunity to restructure their civil heicopter portfolios while their fixed wing business is boyant.

Thus the Pumas may end up effectively withdrawn well before the AIBN issues its final report and whatever that concludes.
Yes I agree. That is the Big Picture
Well Said!

Oldlae

29th May 2016, 12:23

AW009
Thanks, I missed that reference.

buzz66

29th May 2016, 12:31

Airbus = Mast stress causing Conical housing to rupture as a result of Sus Bar or Foot Fail

So the vertical force on the Barby Plate can withstand more force in a variable angle to the TQ in which it's design was intended enough to shatter the Conical housing.

Good luck selling that

Like to see the sales pitch on that Bad Boy!

lynnx

29th May 2016, 12:33

AW009

29th May 2016, 12:42

Letmein: … this catastrophe was caused by a "maintenance event(s)".
Maintenance events are not only a question of human error, but also of functional and fail-safe design. And up to now there are’nt any evidences given for maintenance events, although this might be welcome by AH.

buzz66

29th May 2016, 12:49

Some have said, on here, that the Puma family has run up 9 million hours over all marks.
In that time it has had 3 visualy similar (tho not causal) MRH failures where we can ALL graphically imagine the results.

My questions are;

1 At what point does the statistical likelyhood of this event occuring 3 times stop being chance and become an inherant weakness ?- for whatever reason.

2 Does any other type (same operating area/same hours) have similar record of such a failure?

We should remember that as far as the "public" is concerned an aircraft loss is an aircraft loss - "most" people will neither know nor care whether it was caused by human error or mechanical failure. They will simply have the preception that a newer (or different) aircraft is safer simply because they,ve crashed less !

I think it unfair that on aircraft types that this is the case - but, how long did the chinook family survive public opinion?

On a personal note - ever since I saw the picture of the MRH buried in the ground with an intact strut minus its lower attachment pin, I,ve had a bad feeling.
AAIB and AH will have the final say.
Holy Crap really...You should quit while no-one still knows who the hell you are.

Where to start..

9 Mill flights hours has mostly be carried out by the good old L & L1's thank you very much!!!!!!!!!!!!!!!!! Both Model's are still flying right now.
So you clearly don't work for Airbus or you would already know that.

1. Because the bloody Jesus bolts all came from the same cause. the gearbox failed...It doesn't matter what caused it every time the fact remains, the end result NOT well received.
2, Ohh dear refer above

I simply cannot believe you actually put this in in print to anyone...Fark me do you deserve everything about to come your way, Hang on for the ride!!!!

We should remember that as far as the "public" is concerned an aircraft loss is an aircraft loss - "most" people will neither know nor care whether it was caused by human error or mechanical failure. They will simply have the preception that a newer (or different) aircraft is safer simply because they,ve crashed less !

9 lives

29th May 2016, 13:23

What I find distressing about all crash threads is the almost desperate attempts of some contributors to apportion blame. ......... there has been a common theme since that post which I find depressing at best.

Perhaps it's not so much to apportion blame, but to understand a cause. Understand the cause to reduce the chance it could reoccur, particularly as a result of a factor introduced by the person speculating. This is a personal growth/learning exercise.

Personally, other than for grossly malicious action, I have no desire to point at a fellow aviation person, and say "you did it!, you're in trouble". I wish much more to do my part to understand and prevent unsafe situations. In this case, I have considered factors which may be involved here, and that will make me a more safe aircraft maintainer in the future. Had speculation not occurred in this forum, I would not have those better ideas, which will now stay with me to make my aircraft more safe. That is irrespective of the outcome eventually found.

Several times I have maintenance check flown an aircraft and found a maintenance failing - which was the purpose of the flight! I've not returned and waved an ugly finger at the maintainer and said "look what you did!!!", It's been I have found this, and it needs to be corrected before I'll sign for the aircraft, can we work this out, and I'll take for a flight afterword.

Sensitivity to families and our peers is great here, and empathy for someone somewhere who might have a big lump in their throat right now, because they do understand the cause . But, I like the discussion, and am learning from it.

lynnx

29th May 2016, 13:41

Hey Buzz,

The last time I checked we were allowed our own opinion.

There are 371000 views on this post.
That represents about 0.000053% of the worlds population.
Hence the comment "most people"
Even allowing for interest drift.

The Public (you and I) DO NOT KNOW WHAT CAUSED THIS ACCIDENT
Do you? For sure, and in court defendable?
Well, we,re waiting.
No, I didn,t think so.

My question 2 was genuine.
Does any other type have any history of MRH detaching?
I know of one....you?
Let us all know.

I apologise if I have offended.
Best I hide before "anyone finds out who I am"

Variable Load

29th May 2016, 14:14

Wow, lots and lots of posts from individuals who previously haven't posted very much!

We wouldn't be using more than one profile now would we? :E

Satcomm

29th May 2016, 14:49

Lynx,

Some have said, on here, that the Puma family has run up 9 million hours over all marks.
In that time it has had 3 visualy similar (tho not causal) MRH failures where we can ALL graphically imagine the results.

My questions are;

1 At what point does the statistical likelyhood of this event occuring 3 times stop being chance and become an inherant weakness ?- for whatever reason.

2 Does any other type (same operating area/same hours) have similar record of such a failure?

The S61 had at least 3 aircraft chuck a blade back in the late 60s to early 70s. All resulting in a crash, fatally injuring everyone on board. Not the exact failure (rotor head detaching) but same end result. Not sure how familiar you are with aircraft but the S61, prior to the S92 was the Super Pumas main competition. So that happened back then (3 very similar events) and when did we retire the S61? Some 35 years later, as the workhorse of the offshore industry. Most would love to jump back onboard one tomorrow. Mind you, we could not fear monger on Facebook and other forums back then. In fact, the public had to wait until the accident boards revealed the true facts via a live broadcast or new article. Nowadays, the 225 was doomed by the public before the preliminary report was even issued. Thankfully this won't come down to what the public think! The AAIB will complete their investigation and we will carry on from there. Maybe it flies again, maybe not!

Also note, the 3 blade chuckings, were all S61s ... Not a variant of.

Noiseboy

29th May 2016, 15:17

Super Puma fleet hours are 5.2 million.

4m on the L (580 a/c)
730k on the L2 (90 a/c)
546k on 225 (268 a/c)

Plus a few on the H215.

helicrazi

29th May 2016, 15:28

Pretty sure a Bristow 225 just flew over me, how did they manage to get the pilots in it?

not 100% standing by to be corrected!

lynnx

29th May 2016, 15:39

5.2 million, sorry .....I,m sure someone can narrow that down.
Whatever ... my point being ...do three visually similar failures point to a design flaw or simply 5.2 million hours?
Does any other aircraft have this track record with 3 failures for the same reason?
S76 blade cuffs?
Gazelle tie bars?
207 jesus nuts?
139/189 tail rotor blades?
s92 filter bowls.

Do any other aircraft type even have this many hours? Whats nearest to the puma?

So many question

Steve Stubbs

29th May 2016, 16:25

S61 blades being metal had an inherent weakness in the early days as a fatigue crack of the spar under the skin was not detectable easily. Having worked out the weakness following blade losses, a cockpit warning of coming problems was developed involving pressurising the blades and detecting pressure loss due to cracks. There was also a physical tell-tale with tester on the blade root itself.

The result was a solution to an identified problem - that worked. I had several BIM warnings during my 4500 hours on the S61, one was real, the rest spurious electrical problems. In flight actions involved increasing the NR to 102% to increase blade rigidity while finding dry land or a platform to set down on.

I never flew the 225 - after my time( but did 3500 hours approx on the AS332L). I worried more about the NF governing system which caused several total losses but which was never fixed during my time on the beast.

Magjam

29th May 2016, 16:32

There is a limited amount of information released about the onset of the LN-OJF accident, but I have noted some similarities between it and the G-REDL accident, and I want to share my observations. First the source material:

G-REDL Accident Report: (https://assets.digital.cabinet-office.gov.uk/media/5422f86aed915d13710006cb/2-2011_G-REDL.pdf)
Directly after the loss of MGB oil pressure, the helicopter deviated from its cruise conditions. With only four seconds of flight data (before CVFDR recording seized), analysis of the helicopter response was limited. During these four seconds, the helicopter initially rolled left to -11.3° before rolling right to 9.1° within two seconds. Magnetic heading increased by 30 degrees.

The recorded flight data was provided to the manufacturer who ran a simulation to analyze the consistency between flight control inputs and the helicopter response during the final seconds of operation. The results indicated that, two seconds after the MGB oil low pressure warning, the helicopter was no longer responding normally to flight control inputs.

Recorded fault messages downloaded from the SMDs revealed that, at approximately the same time as the final radio transmission (20s after MGB oil low pressure warning), data from both the Heading Sensor Units (HSU) and the radio altimeter was lost to all four SMDs concurrently. The radio altimeter is located in the tail section of the helicopter on the shelf above the CVFDR, and the HSUs further aft.

Damage to the tail boom of the helicopter confirmed that it had separated from the fuselage prior to the impact with the sea. It had suffered from multiple main rotor blade strikes on the boom and at the base of the fin. Damage to the tail rotor drive shaft was consistent with the shaft rotating when it was struck by the main rotor blades.

LN-OJF Preliminary report: (http://www.aibn.no/Luftfart/Undersokelser/16-286?iid=19827&pid=SHT-Report-Attachments.Native-InnerFile-File&attach=1)
The recordings on the CVFDR showed that everything appeared to be normal until a sudden catastrophic failure developed in 1-2 seconds. The CVFDR recordings ended abruptly at the same time. A spectral analysis of the CVR data has been carried out. There was no obvious indication of an abnormality before the sudden detachment of the rotor head.

LN-OJF Eyewitness statement: (http://www.nrk.no/hordaland/oyenvitne_-_-jeg-sa-at-rotoren-falt-av-_-deretter-gikk-helikopteret-i-bakken-1.12924223)
I was looking at the helicopter as it was flying normally. Then after a few seconds it started veering back and forth quite substantially followed by 3-4 quite loud bangs where we then clearly see parts coming off of the helicopter. A few seconds after that there is one additional bang after which the helicopter goes straight down and the rotor has come off.

In summary, it seems that two things happened shortly after commencement of the respective catastrophic events:
1. Both aircraft apparently veered back and forth initially.
I will not attempt to try and explain the exact reason for the "veering" in either accident, but I found it interesting enough to remark the similarity.
2. The CVFDR on both aircraft seized recording after 2-4 seconds.
As for the CVFDR stopping so prematurely in both cases, consider the following:
- In the G-REDL case it has already been documented that the MR blades struck the tail-boom multiple times, and that it eventually seperated prior to impact with the sea.
See photoshop illustration of G-REDL. (http://imgur.com/s6cRUIx)

- In the LN-OJF case I believe that the MR blades struck the tail-boom as well. I base this belief on my observations of the wreckage images and videos released publicly. From watching the chilling video of the falling rotor (https://www.youtube.com/watch?v=G9yrX0gaVug&t=00h00m06s) hub frame (http://imgur.com/9d4rUBO) by frame (http://imgur.com/C6bUMLj), I'd argue that one can see several blades damaged (some severely) before hitting the ground. The approximate pattern of damage can then be confirmed by looking (http://imgur.com/5nts44t) at the images (http://bt.mnocdn.no/incoming/article3590230.ece/ALTERNATES/w980c169/IMG_9370.JPG?updated=030520161308) of it on the ground. Damage to the tail-boom itself can be seen (http://imgur.com/3KCv30m) in several (https://imbo.vgc.no/users/vgno/images/cb7fc37611d46b8d093995898934f6af.jpg?t[]=crop%3Awidth%3D5760%2Cheight%3D3840%2Cx%3D0%2Cy%3D0&t[]=maxSize%3Awidth%3D654&publicKey=drpublish&accessToken=f4ceffd062e30896ace9c0b2a93cec61b7223ede94b1e7b2 1b352c6202a27ea7) different images (http://imbo.vgc.no/users/bildespesial/images/81e7c0a24f41433959c55e76ca545557.jpg?t[0]=resize%3Awidth%3D1024&accessToken=c6bac0b4179d0900826b9734b84905f4d2b84fe07945acfb 1b473a1dae043eb4), as well as in this video (http://www.vg.no/nyheter/innenriks/helikopterstyrten-i-hordaland/hentet-opp-halen-fra-ulykkeshelikopteret/a/23671612/) where it is being hoisted out of the water.

So what does this have to do with the CVFDR stopping abruptly? Well, while I cannot say for sure which CVFDR was installed in G-REDL, the one installed in LN-OJF have been pictured in press releases (http://imbo.vgc.no/users/livestudio/images/68711a1e13bc4ab1dc7d2e0bf1837c15?t[0]=maxSize%3Awidth%3D1920&t[1]=maxSize%3Awidth%3D600&accessToken=a2005987e934187bf30aba8417db8f04911dd58b2c98159f 14cd6621911c2539). It is a combined CVR and FDR from Honeywell, see manual here (https://www51.honeywell.com/aero/common/documents/Data-_Combined_Recording.pdf). The location where it is normally installed in the helicopter (L1, L2 & 225) is the forward port side of the tail/cargo-hold wall as far as I understand it (see final image). To avoid overwriting the latest data after a crash, the CVFDR will stop recording if:
1. It receives no powerThe CVFDRs in the puma fleet should AFAIK be connected "direct battery", meaning it is among the very last of the essential electrical consumers that should lose power after failure of the generators.2. Its immersion switch is triggeredIt was not immersed in water at the time it seized recording.3. Its inertia switch is triggered (6g)
I propose that one or more MR blades hit the tail-boom and the resulting G-load, however short, triggered the inertia switch. This, in my opinion, is the reason it stopped.

Photoshop illustration of LN-OJF. (http://imgur.com/w09bq2m)

TL;DR: I note some similarities in initial aircraft behaviour as well as hypothesize that the reason for the CVFDR seizing recordings only seconds into the catastrophic events for both G-REDL and LN-OJF, is due to MR blade strikes on the tail-boom and thereby triggering the CVFDR's inertia switch.

Nadar

29th May 2016, 17:16

You wouldn't trust the RFM (Flight Manual) that is issued by Airbus Helicopter?
More Generally, you don't trust cars, planes, restaurants, soap, toothpaste??

No, I generally don't trust that information coming from commercial sources is truthful. That doesn't mean that I dismiss anything that's there, but there are loads of claims made about cars and planes I don't trust, I don't trust that a restaurant deliver the quality or use the raw materials they claim, I don't trust that soap or toothpaste does all they claim to or that there isn't any ill effects that's not mentioned. I think anyone fully trusting such information is naive.

But then you go on to say that they have to present the final report.. So which is it??
Now you're just twisting my words, I didn't say that they have to present the final report, I said that as I understand it they won't until they are convinced they have figured out the true cause. If that can't be done, I guess the final report will either never be presented or that it will say so. In either case my point was simply that I don't see how you can claim that they have to come up with the cause "soon". What dictates this is the investigation and what they can figure out, not the calender.

henra

29th May 2016, 20:45

Holy Crap really...You should quit while no-one still knows who the hell you are.

Holy crap.
Why are you so desperately panicked to insist on one cause despite not even the Investigators being sure about the cause at this point in time. Did you think about talking to your psychiatrist about this?

A little bit of speculation is fine but what is all this crap with you Amateur accident investigators all about? And any one who doesn't follow your amateurish reasoning blindly will be madly attacked by you.

Is it asking too much to wait with the final verdict until someone KNOWLEDGEABLE has come up with some real evidence (not Armchair evidence)?

(Taking this one of your posts randomly I could have chosen any other one.
Here's hoping your not a Professional Pilot (Or professional anything else for that matter)). Rant over!

industry insider

29th May 2016, 21:43

Super Puma fleet hours are 5.2 million.

4m on the L (580 a/c)
730k on the L2 (90 a/c)
546k on 225 (268 a/c)

Plus a few on the H215.

950,000 on the S-92 last time I had an update but probably closer to 1m now.

TylerMonkey

29th May 2016, 22:57

Is it possible to determine where the front suspension bar was positioned in relation to the gap in the fractured ring gear ?
Would be interesting if they were closely aligned . . . . just an idea.
http://i86.servimg.com/u/f86/11/94/64/62/ringge11.jpg

Magjam

29th May 2016, 23:25

Tylermonkey, look at 3D computer image on the next page of where you found that picture in the updated preliminary report. (The one with the pieced together conical housing.)

The breach in the ring is at the 4-5 O'clock position, with the forward suspension bar being at 12 O'clock.

Coincidentally(?), the breach was reported to be in the 5 O'clock position on G-REDL's ring as well..

A breach in the circumference of the bevel gear support plate at the approximate 5 o’clock position, matched the location of the vertical split in the epicyclic ring gear.

TylerMonkey

29th May 2016, 23:36

Thank you !

OnePerRev

30th May 2016, 01:47

those gears and bearings show distress over time. Not a few seconds. More like several or many minutes.
Sun gear teeth rounded, wear, not sudden fracture.
Already discussed the bearing race of the fractured planet.
LN-OMG showed gearbox capable of pulling out the support plate rather than break apart at conical housing.
Suspension bar theory was likely included by aibn to satisfy AH. While all is preliminary at this point, probably nobody technical in investigation really thinks it's the strut. Only scenario is that lack of strut support put abnormal high loads onto conical housing. Over time the housings develop fatigue fracture and begin to deflect. Misalignment then cause gear and bearing distress. Gearbox gives up the ghost and then.... Problems with that chain of events is you won't get gearing distress until housing fracture. And loads sufficient for that would be evident at support plate as well.
Perhaps more likely it starts with epicyclic.
Did AH fix the earlier problem or just improve the possibility of detection?

jimf671

30th May 2016, 02:54

Looking at the G-REDL description of roll and yaw, although accidental control surface inputs will also be part of the picture, the motions appear consistent with gyroscopic forces occurring when a downward force is applied at the rear followed by the opposite.

I expect that this is indicative of the supporting structure coming apart piece by piece. We know that the root cause in G-REDL is in the epicyclic but still these forces are consistent with the suspension bar arrangement progressively failing. I conclude that whatever the root cause in a rotor detachment accident there is going to be a confusion of evidence as the forces on the rotorhead rip things apart.

OnePerRev

30th May 2016, 03:21

That's why it's so critical to get all the parts. Investigators evaluate for clues on sequence and time relationship.

Conical housing fracture surfaces may be inconclusive on fatigue evidence due to corrosion from seawater.
Strut should be straight forward. Impact, fatigue, overload, should be preserved enough.
Lab evaluation of gears and bearings will take time but they would already know about heat generated and wear modes. Even if they see fatigue they will still need to find out why. The missing carrier may hold clues about the puzzle.
If AH farmed out the gearbox design as suggested then they may not even have the expertise themselves.
That makes the fast interpretation all the more questionable.

whoknows idont

30th May 2016, 05:38

AIBN could have clearly stated what they found and what was still missing in their initial version of the preliminary report. Instead of beating around the bush with some vague hints and suggestions.
Overall I don't see any new major findings in the revised preliminary that they couldn't have already put in the initial version, or am I missing something?

Looking at just the reports, some internet discussions and magazine articles, it seems like they let external pressure influence their work a little too much, reacting rather than acting. But I must admit that's a bit far-fetched without having way more insight into the process. Although I'm still startled by the fact that they let the journalists wander around the wreckage.

birmingham

30th May 2016, 09:57

I must say I am still, about a month in, struggling to make sense of all this.

AH came out 48 hours after the accident and effectively said this was not an epicyclic incident.

AH have the most experience with this machine. They know that a full investigation is ongoing which will, if it is in anyway possible, get to the bottom of this and publish a report. Following that report they know litigation will be inevitable.

So surely they must have access to the engineering equivalent of a smoking gun.

But, one month in nothing of that nature has been made public. There may well be solid reasons for this. But, even if that is the case the AIBN clearly think that the "doors they need to close" consist of more than tidying-up the evidence ahead of a final report.

The regulator reviews the advice of the manufacturer and AIBN and decides if a suspension can be relaxed. There is clearly a difference of opinion rather than emphasis between the manufacturer and the investigator.

The latest statement made by AH is carefully worded to say suspension failure is the only probable scenario but don't say why. That is understandable for legal reasons.

So what we can't know from the public statements is whether

(a) AIBN believe, given the 3 recent gear related accidents, epicyclic failure must be explicitly ruled out as the primary cause. That in order to do that 100% they need supporting mechanical and if possible metalurgical evidence from parts as yet unfound

or

(b) this is rather more than a door closing exercise and they don't buy the suspension strut theory.

So I am back to square one. Surely AH would not be releasing these statements unless they can stand them up.

AW009

30th May 2016, 10:20

birmingham

30th May 2016, 10:58

I believe with the ring gear as shown in http://www.pprune.org/rotorheads/578298-ec225-crash-near-bergen-norway-51.html#post9392368 the game for AH / H225 in offshore ops (at minimum) is over. It is only a question of time till the final report is presented by AIBN.

A minimum chance might be given, if AH and AVIO would work 24/7/365 on completely new solutions, but those also will be evaluated and certified and this takes time. A stopgap solution I don’t see on the horizon due to the already ordered grounding of Super Puma.

This is meaning the remaining operators have to work with alternate HC-Types. To switch back to AH / Super Puma after approx. one year or more might therefore be a very theoretical question.

To quote former Chairman Gorbachev: "Those who are late will be punished by life itself".

As I said previously I dont know who is right but ...

If you are correct and frankly (given the current financial situation) even if you are not, what you predict may well come to pass.

However, for AH the situation could be much worse than that.

AH are part of EADS and the last episode halved the groups net cash position. The CEO (who knows a very great deal about the Puma) is looking at this strategically and you can bet Toulouse is looking over his shoulder.

We have more than enough 92s to cope and the AW189, H175 and soon Bell 525 are new if slightly smaller options for operators. So a re-engineered Puma may be a total non starter.

So maybe AH will bite the bullet and go for an entirely new machine but as the FT said last time; by the time AH have a really new airframe, the market may have gone.