Gouli,

Indeed, the crack has to be initiated somehow and it appears from the report that it was from one of a series of micro-pits 15mm - 16mm from the top face of the bearing, so all of them slightly below the line of maximum Hertzian pressure at 14mm but where sliding contact might begin. That it was not one isolated micro-pit (a rare occurrence in itself) but one of several in a row is, I think, a clue as to how it came to exist. Those other micro-pits should give the metallurgists something to analyse.

Plan B
 

Dear All
As we are waiting for the final report , and modification / inspection-cycle or change of manufacturer of certain parts: How many ac are effected ( Norway and UK)
And what have the operators done.
I have followed this thread with great interest , but have little grasp of the local , regional and worldwide consequences for the SuperPuma.

I do compare this with the rudderhardover that B737 did suffer long time ago.
It is do or die, but they found the likely cause and did a good fix!

Anyway, I understand the Norwegian NTSB are mostly respected for not bowing to undue external pressure.

At the end of the day: we can never have main rotors depart without warning like this again. Your part of aviation is inherently more challenging than airliner ops is , never mind the wings going AWOL.

Regards
Cpt B

There was a couple of low key press releases by Airbus claiming the 225 will be returning to service soon.
https://www.flightglobal.com/news/articles/h225-helicopter-to-return-to-full-flight-status-soo-438783/

https://www.flightglobal.com/news/articles/uk-caa-sees-no-prospect-of-quick-return-for-grounded-438857/

This survey has appeared on one of the offshore sites.
http://www.airbushelicopterssurvey.com/
I dont think they realise how things have moved on

Not exactly sure to understand what you mean here?

I meant the 225 has been replaced and even if was introduced again the strength of feeling against flying in it is too great to overcome.

Interesting articles. Regardless of one's individual opinion, the market doesn't really need the H225 at the moment. S-92s took up most of the slack and the Super Mediums are taking slots where they fit which will free up more S-92s to use where a heavy type is definitely required.

TM is probably right about the current market needs.

Super Puma on the front page of the P&J again today. Plenty of opinions inside from people who know less than nothing about helicopters. Plenty of mistakes as well. (H255?!)

https://www.energyvoice.com/oilandga...rth-sea-skies/

I wonder if they will share the results?

I am sure that if a lot of E&P workers were to reply positively then they would.

More relevant is that the industry in the North Sea changed. Operators/customers increased the use of medium types and many more of these have been introduced. I can see the use of the S92s being reduced and the mediums taking up a bigger share of the market.

What the Bergen crash seems to have been is a catalyst for this change.

AH have a decision to take on their new large helicopter, the mock-up shown in Paris asking as many questions as it answered. This survey is likely to have been issued partly to tell them how closely it can resemble the 225 and still sell, as evolution rather than revolution is always the preferred design approach.

Returning the 225 to the North Sea in any significant quantity has always seemed unrealistic in my opinion - but when you have a lot of history and personal in investment in a product it is very hard to let go.

I think a number of the operators are able to claim compensation from Airbus during the time the 225 is grounded - much of this income is then ploughed into medium types, with the remainder kept for other operational costs or, in the rare case given the poor state of the industry, profit. When they are no longer able to make a claim (if/when the 225 is cleared to fly again), they may have to revert back to using it purely for financial reasons. I think there is still a market for them there - the S92 is not without its own problems.

While the oil price is in this current regime, there will be increasing moves away from heavies as for most oil companies, the main driver in all decisions is price. The costs of heavies make them uneconomic in comparison. The H225 is dead in the water commercially unless Airbus can cut their hourly DOC/ PBH dramatically and the leasing companies accept the hit and drop the lease rates dramatically. Even then, it's reputation is still in the toilet.

It goes back to the Air Advisers and C&P people at the oil companies - who is going to sign up their workers to an H225 contract? Answer - no one for the foreseeable future.

IMHO AH would be better off focusing on selling what they have to militaries and spending their time and money creating something else.

It goes back to the Air Advisers and C&P people at the oil companies - who is going to sign up their workers to an H225 contract? Answer - no one for the foreseeable future.

Agreed - if you don't work in E&P it is easy to miss the commercial point. All the major helicopter people were suffering long before Bergen

CGG a major services company baked by the French state filed for bankruptcy recently, their revenues are only 30% of what they where before the slump. Many other service companies are 50% or less. So the problems go beyond the 225 or helicopters. Since Bergen the North Sea has moved to the S92 and mid-sized types but there have been no significant new orders for new builds announced to meet the gap other than a couple to be used for SAR contracts for Statoil. It has been about redeploying existing machines.

Even if this hadn't happened there would have been a big downturn in demand for helicopters. The timing of the Bergen incident was such that it was probably the final nail in the coffin. The 225 and other Pumas certainly have some sort of future but there are few signs in the O&G market that it will be needed here.

when you see that AW is dumping 169 at high 6 mil you know wheres the market.

But OEMs somehow come up with the same conclusion that the market will bounce back in foreseeable future. And they are burning cash flow to flood the market when low so they are "prepared for the market comes back".

The problem this time is fracking and to a certain extent renewables. As soon as the price moves up the US completes more wells. Renewables provide a small but no longer insignificant share - this will increase. Supply will not be an issue for some years,if at all. The N/S will still survive but will be leaner - with smaller operators and a greatly reduced cost base. Statoil will hang on in there; there have even been new discoveries - one very significant. But increasingly it will be the preserve of specialists. - but there will be no return to the status quo of mega platforms and mass transit.

It will be a very different North Sea with different transport needs.

I don't think this video from AH, a few months old, has been linked here.
Kinda marketing, but interesting nonetheless.

Disclaimers: I haven't flown a fling-wing in decades, and when I did it was for the Big Green US team, all we had back then was a chips light, driven by several magnetic sensors in the fluid path. My experience with vibration acoustics is also more than 25 years old, so take that as a caution.

Back when I worked with Solar Turbines and Spectral Dynamics, it was relatively easy to monitor, discover, and trigger on FFT characteristics in a turbine and gearbox. I'm considering the rapid detection and prevention of the catastrophic failure which was found in this accident.

By use of the FFT algorithms in the detector hardware and software, we were able to build a characteristic signature of every turbine and gearbox built and instrumented. In some ways, the signatures are very common, and in other ways they are always slightly different. Think of the concept of a fingerprint and one will get the general idea. In the video above, at the 8:15 time mark you can see a brief image of the vibration signature of some rotating asm(I doubt it's a helicopter gearbox, but hard to say). By use of threading and setting up triggers on both amplitude, frequency, and harmonics I'm inclined to say that discovery and alert of an impending failure once spall 3 or spall 4(almost surely) would be possible.

The amount of vibration noise would be of greatest concern, where specific anomalies could present a trigger warning, which would induce a 'false positive' alarm for potential catastrophic failure. The S/N ratio, and type of detection would require sensors inside the MGB, as I think outer case sensors would not be sufficient to capture the ringing and vibration in an encapsulated gearbox bathed in lubricant. This would require further study.

As I mentioned, my depth of knowledge on this is quite old, but back in the 90s we were able to detect common gear spalling in planetary gearboxes for industrial and non-flight aviation systems, most commonly GPU and remote start mechanisms, as well as fixed generators.

Sensor location: At Spectral Dynamics I was a small part of a team which took great interest in instrumentation for failure discovery. There was clear evidence that the location and orientation of the acoustic/vibration sensors for various gearboxes was critical to gathering useful transient data for the electronics to evaluate. For example, using the main mast as the natural Y axis, and the plane of the planetary/sun gears as the X axis, it would seem that having the piezio-electric sensor aligned with the X axis is most effective. However, there are cases where the sensor alignment has shown better response when the vector moment is some degrees off axis, and aligned slightly to the Y axis(something to do with the materials di-pole moment of inertia? Beyond the scope here).

We only got a small taste of what additional sensors, real time analysis is taking place. Which is sad, because I think that even with this type of very small spall propagation it would be possible to detect using internal sensors in the gearbox, and characterization of the vibration signatures in real time. Of course, each gearbox changes its 'tune' with age and strain, but anomalies are really not very hard to detect, and the spalling taking place in what I've seen in the report, could quite possible have been detected, and a warning issued well before the complete failure. I will respectfully say that I have no idea how long spall 1 proceeded to spalls 2, 3, and 4 but my recall of the instances we had at Solar were that it was many operation hours before the system would self-destruct. Also, before anyone points out, I will point out that our sensors, and all gathering and analysis data was ground mounted, and presents a significant weight in a helicopter where weight is the enemy.

YMMV

Update on the final report
 

As reported elswhere on this Forum, the draft final report was sent for consultation to interested parties on the 9th of February with a deadline for comments on the 10th of April 1018.

A report in the media today has a statement from the head of the aviation department at the AIBN that the review of comments has been time-consuming due to the volume of comments and "objections". The review resulted in some changes and an amended draft final report was sent for a second round of consultation to some of the interested parties. The deadline for this second round was on the 13th of June. He also states that the final report should be out before the summer hollidays (which in Norway is about a month earlier than most of Europe.)
The article also for some reason mentions the possibility, according to Annex 13, for a State (formally) to append a dissenting view regarding technical aspects of the Final Report "upon which no agreement could be reached".

I wonder which interested party made the largest volume of comments and objections? The one that has the most to lose if the AIBN publishes what they really think presumably :}

Doesn't Airbus realise that their biggest issue now isn't a technical one, but one of trust? Behaving in such a way to try and protect a dying product will do nothing to repair damaged reputation.

Publishing a "dissenting" appendix by an OEM is a pretty rare occurance IMHO, but was exactly what happened in the accident report for the 1980 Malaysian SA330 Puma fatal crash in Brunei. Which was due to "second stage epicyclic module planetary gear fatigue failure caused loss of the main rotor" :eek: :eek:

I do find the way that Airbus has behaved since the day of the accident to be very disappointing and actually worse than I would have ever imagined. :(

The PR issue notwithstanding....will the Final Report actually determine the cause for the failure of the component(s) that led to the fatal crash?

That is the real issue....with the PR thing merely being collateral damage AH brought upon itself.

I question the wisdom of letting an "interested party" write parts of my Report....after all....don't they have an interest in how the Report turns out that is plainly a challenge to the truth at times?

It could well be the parties that called the finding before actually finding anything having hard time to back track their claim?