Taking this statement at face value and given the difficulty EC had in replicating the failure if EC can now demo a failure in flight then doesn't it suggest that requires specific actions to do so....which could also be avoided and therefore the shaft won't fail?

OR

We can't predict the initial crack the flight testing is done on one already cracked but not totally failed? And we are testing what exactly?

Which is it??

Either way seems to me the conclusion now can only be either the EC225 has flakey shaft material beyond the material spec change they highlighted as a possible cause initially OR its not being operated as it was intended OR something has changed and wasn't fully tested or understood.

This is an interesting clip, about a month old.

Interestingly across the panel everyone wants to put distance between themselves and a timescale. Not one of the group wants to be tied to remarks on date. They lie (see around minute 27) when they talk about the comments regarding the return to flying in the EC225. The comments attributed were not as Les Linklater suggests to fill column inches. They were comments from a transcripted earnings call. The words were absolutely said. If you want to back track from it later - fine but they were said in context.

You can also see ref to V12 FADEC (15m) and Aberdeen operation (23m), the fact there are no other cracks in the entire EC225 fleet.

Interesting context to see where they were in mid-Feb and how that will relate to 6 weeks later and of course the statements around the return to flying only once the cause is known.

What's the latest news concerning the EC225? When a return to normal operation will be expected in the North Sea?

New solution to enable EC225 helicopter to return to service

Details Published on Tuesday, 02 July 2013 09:54 Written by Paul Williams

Helicopter Safety Steering Group: Eurocopter solution is a step in right direction.

Step Change in Safety’s Helicopter Safety Steering Group (HSSG) welcomes Eurocopter’s announcement of a solution that will ultimately enable the EC225 helicopter to return to service as a first step in a phased assurance approach.

The European Aviation Safety Agency (EASA) and national aviation regulators are required to approve the solution before any return to service.

HSSG is working with its members including employing companies, helicopter operators, trade unions and workforce representatives to ensure that the EC225 will be safe to fly.

Les Linklater, Step Change in Safety’s team leader, said: "HSSG awaits with interest the regulators’ announcements of recommendations and guidelines. There will be no short cuts in the journey towards a return to flight for the EC225 and the workforce will be fully informed on the progress to ensure transparency.

"HSSG is beginning to receive and review reports from the validation process carried out on behalf of Eurocopter, the helicopter operators and also HSSG in order to ensure that there are the required independent layers of assurance for the investigation techniques, root cause analysis, crack propagation and future safety improvements and barriers."

Bristow hesitant to put back the 225 fleet back into Service....until they are confident in the situation.

Interesting quote by the CEO Chiles regarding Commercial Pressure trumping Safety.

It would appear CHC is taking a different view and moving to have their fleet back in full operation sometime this month.

How does that square with your comments and concerns?


Bristow will use caution in returning EC225s to service | Vertical Magazine - The Pulse of the Helicopter Industry

Isn't it a paradox.

Yet, no one I know in the industry, knows what is going on. Everybody is asking, but absolute silence from Eurocopter.

Tango, slightly unfair considering a very comprehensive Safety Information Notice on the subject was published by EC a few days ago (30th June)

There's plenty of information available from various sources for the offshore community.

The European Aviation Safety Agency (EASA) published today an Airworthiness Directive which approves and mandates the technical solution proposed by Eurocopter for its EC225 fleet. The objective is to fix the unsafe condition created by the shaft failure of two EC225 helicopters in the North Sea in 2012.

The Eurocopter solution comprises of a set of modifications and inspections which aim at monitoring and detecting vertical shaft crack conditions and reducing the likelihood of any shaft crack initiation. When complied with, this solution ensures safe and airworthy operations of the EC225 type.

EASA will continue to work closely with Eurocopter, with the relevant National Aviation Authorities and the accident investigators to ensure that the fleet is operated safely, and may update its directive based on further investigation results.

EASA Airworthiness Directives Publishing Tool

..and CAA
 

How's about an Engineer tell us Pilots what all this says please. Do keep it simple so those of us who are mechanically challenged can understand it.

I seem to read as saying the Shaft must be given an Ultrasound every Eight Flight Hours....but then I only devoted a half hour to reading the thing!


EASA Airworthiness Directives Publishing Tool

.
Hello SASless,

it's from EC so it's of course PR but it's from today and the video is quite interesting and also the "return to flight situation update" at the bottom right :

EC225 Knowledge Centre

.

- Residual stress
- Hotspots (stress hotspots)
- Active corrosion

Presumably, the active corrosion is a case of the passivity expected of a Chromium-Molybdenum alloy steel breaking down in the presence of a moist paste of wear debris permanently overlying a residual stress hotspot due to centrifugal force and the shape of the internal surface.

What is the source of the moisture?

Is it condensation in the gear case?

If so, are idle aircraft at greater risk?

1) Of course there is atmospehric moisture at the end of the day due condensation

2) What do you mean by the "gear case" exactly? If you mean gearbox then yes, there sometimes is condensation

EC have put out this video and information. More PR and spin than detail but that's expected.

www.ec225news.com

I think its a nice and well structured site to be fair. I'm not sure when it was published (the site) but its a great step forward. Fair play to whoever pushed it forward.

Its pretty belt, braces and kitchen sink now and you can't see them having issue with the 225 in the interim period but couple things that seem odd:-

1) what testing and analysis was done around the revised shaft that was fitted to the aircraft in the 1st accident (given it was pretty low time 167hours).

2) what drove the 2000hr TBO and 20000hr life for the 225 shaft.

It just seems odd to have been caught out this way with what look pretty fundamental issues.

CHC planning a return to service on July 18th in Oz I believe. Not sure who the first customer will be....does it begin with S?

The European Aviation Safety Agency (EASA) has validated Eurocopter's safety measures to prevent the shaft failure that led to two EC225s ditching in the North Sea last year, paving the way for the suspended fleet to return to service.


The news appears to signal the beginning of the end of what former Eurocopter CEO Lutz Bertling described as the "biggest issue" the company had faced in its 20-year history, as UK and Danish national aviation authorities suspended offshore EC225 flights following the second ditching in October 2012, affecting a total of 80 aircraft.


Eurocopter has been working on a fix to the issue since that time, and said a crack in the bevel gear vertical shaft - the root cause of the ditchings - was caused by a combination of three factors, all of which must be present to initiate the problem.

1. Reduced fatigue strength due to residual stress introduced during the shaft welding process
2. Reduced fatigue strength due to stress "hot spots" associated with the shaft geometry, in particular the surface roughness and the shaft shape
3. Very exceptional active corrosion in localised areas of the shaft.

The company said its new prevention and detection measures will increase safety beyond certification levels, and will be integrated in the standard maintenance procedures. The preventative measures include regular cleaning of the inside of the main gear box vertical shaft, a new oil jet for improved lubrication, and a redesigned welding hole plug for certain serial number aircraft. Detection measures involve ultrasonic non-destructive inspections (replacing the eddy current procedure), and a new EC225 health usage monitoring system version - known as MOD 25, that will provide in-flight real time analysis of the bevel shaft indicator. "By employing this combination of preventative and precautionary measures, the bevel gear crack appearing and not being detected has a probability of occurrence of one in one billion," a Eurocopter statement said. "This is a hundred times more than what is required by the certification authorities."


As a long-term solution, Eurocopter has launched a shaft redesign that it said would remove all contributing factors. The availability of the first redesigned parts for retrofit is estimated to be in the second half of 2014.



Following EASA's decision, the UK's Civil Aviation Authority has lifted its operational restrictions, and Eurocopter said it expected other national aviation authorities to lift their restrictions shortly.


"This is a major milestone to ensure that the first EC225s of the suspended fleet can be ready for a return to flight in July," the company said in a statement.

Lots of regulatory/engineering stuffing in these posts, but back to SASless' original question, what does this mean to pilots?

Do you fly any different or still drive around at MCP and toss it back to maintenance at the end of the day? Any change to emerg procedures or training? Are different operators coming up with different SOP's for their pilots?

If the air volume within the transmission housing contains moisture then the moisture can condense and form droplets on the internal transmission surfaces when things cool off after shut-down. If these moisture droplets work their way down into the oil sump then they do not present much of a problem. But if these droplets collect on critical surfaces of highly stressed ferrous components like gear flanks or bearing races (or even a bevel gear shaft) and remains there for even a short period of time, the subtle surface corrosion damage produced can easily be sufficient to initiate premature structural failure of the components.

For this very reason, it is now common design practice to force all air flowing into the transmission housing to pass through a breather device that employs a desiccant element. After a few heating/cooling cycles, the air volume within the transmission housing has been thoroughly de-humidified. I don't know whether the EC225 transmission uses such a device. Based on the reports describing corrosion from internal moisture as being one potential source of the problems, then I would assume that no such desiccant breather system was used on the EC225 MRGB. Maybe someone with a detailed knowledge of the EC225 MRGB design can provide clarification.