"The crash report for LN-OPG took over 4 years and I suspect that while that accident was as tragic the investigation was not as complex. Could be a long wait."

Question for those familiar with accident investigation - why does it take four years for a report to be issued - what actually goes into its compilation that takes so long.

There is an initial investigation at the site and examination of wreckage a while later to attempt to establish the cause. Various components are sent for metallurgical testing, electronics are examined for saved data, flight data recorders are downloaded and interpreted.

Where component failure is identified it may be subjected to further independent testing because in many cases involving scientific investigation the results are subject to interpretation by experts. Different experts may arrive at different conclusions despite being presented with essentially the same findings.

Then there is a need to determine whether any human factors are involved in maintenance or operation of the equipment.

Were there any other administrative failings that led to improper maintenance or other failings.

In every case where a problem is identified, individuals and organisations are offered the opportunity to respond and challenge or justify the findings. This may involve legal procedings through civil courts which are notoriously long winded affairs.

A final draft of the report is prepared and sent to all parties concerned for any final comments or challenges before publication.

A complex investigation being completed and a final report published can easily take four years, especially if several parties are extremely interested in avoiding any blame for an incident.

Although the civil investigation can take a long time, any criminal charges arising will generally take even longer, as that investigation is generally not allowed to proceed until the civil process has been exhausted.

Obviously the reason for all accident investigations is to improve safety and to prevent a recurrance. It is perfectly possible to issue orders grounding aircraft for urgent rectification work to be carried out well before any formal report is issued if the problem identified is serious enough.

So, what if they find such particles? – Conclude that the Type B gear/bearing spalls at or before 300 FH? That wouldn’t be good, would it?

Or, what if they don’t find any? – Eureka!? Or maybe ‘Hey Presto’? The Type B’s are safe??? Try again at 600 FH, 900 FH etc…?

For the 300 FH to have significant meaning the cooler would have to have been flushed when the MGB/epicyclic module/2nd stage planet gears were installed. Is that normal procedure? If not, I don’t think the specific FH would be the important factor here. How about flushing the MGB casing too?

In exchanging all Type A planet gears for Type B’s last year, AH must have accumulated a large sample of used Type A's for metallurgical inspection. Perhaps the answer is that this latest measure is to now, selectively, acquire a sample of Type B’s that have begun to spall and put them under the microscope too.

Sounds logical. Did we get to the bottom of the process that identified a batch of drive shafts in a previous event?

EVEN if all the authorities grant permission for the 225 to fly under their OAC's, who's to say the oil workers and their unions will allow them to board the machine. I know it's a "tainted" machine in their eyes, they have no trust in it.

You can be rotors running about to pick up a load of Pax but if they have been told NOT to board then you can't force them, this is something AH along with the agencies don't get. Look back at the BV234, sat in hangers in ABZ and ENZV

I think you have hit the nail on the head there Impress.
I used to accept the risks of travelling to and working offshore. However the events of the last few years have given me the impression that to the Puma/225 manufacturers are more concerned with profits than the lives that their machines are entrusted with.
I think I might have reluctantly got back into a 225, but my family are adamant that I don't. I respect their decision and have spent the last year retraining in case I need to change jobs. Nearly everyone I know offshore feels the same, it is about time AH realised this and moved on. The 225 is dead and finished. (Hopefully)

Unlikely, since the H225 is still the safest helicopter in its class of all time. That sort of record does not usually happen by chance. All of the alternatives either have worse accident records or are so new that we have no idea what the future holds.

I understand that these things aren't based on rationality, but I wonder if your family has considered that the S92 has had one fatal accident, and the EC225 has had one fatal accident, and it is therefore completely illogical to have a fear of one type and not the other. My feeling is that they are victims of the hysteria and hype that apply to accidents "in our back yard" vs the disinterest in accidents that happen far far away.

I know it may be slightly irrational but it is definitely not hysteria.
The complete lack of confidence comes from the multiple failures of the same components. I accept we don't live in an ideal world but I would have hoped that any failure would be learned from and reliability improved. AH appears to want to get them in the air with a sticking plaster on as soon as possible. I base this on the shaft problems, how many times where we assured it was fixed, and the mgb catastrophic failure occuring twice? What has changed to make this once reliable and trusted aircraft so bad?
You also have to realise that it is unacceptably cramped for 19 people. It may be ok in the front seats but when you cant walk after two hours because there is absolutely no room to move in some of the seats you start to look for reasons not to fly in them. This is a really serious problem that the operators are unwilling to address.

HC,

Would you care to explain your own rationality in separating the EC225 from the rest of the Super Puma AS332 family, even though Airbus Helicopter groups them together as variants in their sales material? Also, would you care to list the variants that use the same epicyclic transmission module as the 225 and, specifically, that used 2nd stage planet gears with Part No’s. 332A32-3335-00 and -02 to -07 inclusive? Would you care to explain why AS332L2 variants are currently grounded in Norway and UK?


jimf671,

Would you care to share your statistical analysis, also with definitions of ‘safe’, ‘safest’ etc.? e.g. Fatal accident, potentially fatal accident etc.

S92PAX’s comment referred to the manufacturer of the product, not the product itself or any nit-picking derivative/variant/colour of it. The behaviour of AH following the Bergen crash supports his assertion, would you not agree? Or do you actually believe somebody forgot to put a pin in a suspension bar?

The poster I was replying to, said his family wouldn't let him fly in a 225, the L2 wasn't mentioned. I was merely replying in that context. There is an awful lot that is different between the 225 and other Super Puma variants but of course the epicyclic is shared with some other variants as you suggest.

It boils down to, if say we went back to flying the EC225 on the N Sea in equal shares with the S92, 175 and 189, whether the next fatal accident would certainly be on an EC225 due to an epicyclic issue. I suggest it almost certainly wouldn't be. More likely it will be pilot error (S92 - its had plenty of near misses) or as yet unknown design flaw (175 and 189).

But that of course is a logical, rational, evidence-based argument. Decisions made in the modern way, ie by ignorance, scaremongering and Facebook, are likely to reach a different conclusion.

What is the evidence based argument here?
Is it fatal accidents/flight hour in the North Sea theater?
Is it not equally evidence based to argue that the 225 has had 2 very unusual failures which remain unresolved, versus none such for the other 3 contenders?

In fixed wing aviation, aircraft that lose a lifting surface get grounded until the cause is resolved. The same logic should apply to rotary wing products.

The evidence base is the fatal accidents and flights hours - not particularly in the N Sea. You say the 225 has had 2 very unusual failures - which two are you referring to? There has only been one fatal accident. The S92 has had a fatal accident, only "resolved" by ensuring the pilots are fully aware of the aircraft's failure to meet its certification requirements. The other 2 contenders are pretty new on the scene and not yet proven. If your contention is that a brand new helicopter fresh from certification is bound to be safe since it has had zero accidents (and zero hours) then both I and history disagree with you. Has there ever been such a helicopter?


I am not suggesting that the EC225 should return to service until after the NAAIB report is published and any required corrective action taken. What I think is foolish is to say that "I'll never fly a 225 again, regardless of anything" whilst also saying "Oooh look, a shiny new 175 / 189 (etc) - can't wait to spend hours in one of those!"
The whole idea that a brand new type is by definition totally safe, is incredibly naive.

But HC, you forget that people only care about the global safety record of an aircraft if the global safety record refers only to accidents/ incidents in the North Sea in a time period determined by self interest! :)

Keep you balanced and logical argument to yourself, some sense might break out otherwise...

(tongue in cheek if that hasn't come across in text)

No great complexity. The number of accidents and number of fatalities is pretty basic.

As stated by others, some of that is not in the North Sea so can be filed under "Don't f3ckin want to think about it."

I suppose I might just be getting senile.....but could you prove that Statement of Fact by providing comparative Statistics that underlie your assertion of that?

THE HISTORY?
Most long-established helicopter types in this class have been involved in hundreds of incidents involving hundreds of fatalities. One type had 33 known accidents, 16 fatal accidents, 116 fatalities in 2016 alone but operates in many territories where reporting is less than thorough. I couldn't count total fatalities because I kept losing count around 2700. Even the much-loved S-61 (incl SK) has been involved in over 400 fatalities and in spite of a much reduced fleet size, accidents, including fatalities, were still happening in 2016.

NEW ERA?
As stated above, we're really looking at S-92, H225, H175 and AW189. Helicomparator has made plain his view on new types and I agree with his position.

For the S-92 (13 years service), I can find 18 accidents (9 of which were in the North Sea), 2 of which involved fatalities, and 18 fatalities, 1 of which was military/paramilitary not involving enemy action.

For the H225/725 (13 years service), I can find 9 accidents, 3 of which involved fatalities, and 21 fatalities. Of the fatalities, 1 was military/paramilitary in training not involving enemy action and 7 were military/paramilitary resulting from enemy action.

H225
The H225/725 therefore appears to have a low number of accidents for an aircraft that has been in both civilian and military service for a substantial period including considerable intense public transport activity, SAR, and military/paramilitary use during warlike operations. It had been in service for 10 years before a fatality occurred and in service for 12 years before a fatality occurred during public transport operations. In comparison to the nearest comparable modern type, its history of stability on floats, means of escape, control of noise and vibration, and gearbox run-dry characteristics are superior. Fatalities in public transport operations are fewer but only through the chance number of POB at the time.

Those numbers do not look very robust. Fatalities are something of the 'luck of the draw' in that the number of occupied seats varies considerably - both up to a maximum of 21 (inc aircrew).

More importantly airframe safety is generally measured in fleet hours. In 60 seconds googling I find the S-92 fleet has approximately 1,000,000hrs (not sure about the military / civil split) and the last quoted 225 fleet hours were around 350,000 which tends to turn those 'statistics' on their heads.

It is however very noticeable that none of the official assessments actually split accident rates into types - a fundamental failing given the topic of this discussion!

FWIW the earlier 332 type have circa 4.3 million hrs.

Sorry don't believe that is correct.

Si

Indeed - from the Airbus H225 portal: