Being knocked over in the street by a falling piece of helicopter would be an unlucky event. Perhaps about as unlucky as going swimming and being eaten by a shark or a crocodile. Unfortunately in Australia in the past week both unfortunate events happened to people who's luck ran out. Any time you get in a helicopter there is a risk of bad luck ensuing which may rear it's ugly head at any time.

Unlucky, but not impossible.

Vauxhall AW109 crash

well actually, yes! if the option is to ditch in horrendous sea conditions then continued flight could well be the preferred option.

Let's not forget that SK implied the S92 had 30-min run dry (even though it didn't explicitly say so) and it wasn't made clear that they slipped past that part of certification by arguing that is was an extremely remote failure.

That would have been fine but the oil filter housing was poorly designed with a poor choice of number and quality of fixings - it became a 'not extremely remote' failure.

The poor suckers in the cockpit lined up the final hole in the Swiss cheese by not following the RFM exactly but they shouldn't have been left in that position by poor design and dodgy certification.

The 225 certainly appears to have a design flaw in its epicyclic gearbox but don't hold the S 92 up as a paragon of virtue.

Maybe not a paragon of virtue Crab but since that horrible event, the S-92 fleet has flown 700,000 hours and managed to keep ts oil in its box where it belongs. Total fleet hours on the S-92 are now around 1 million.

My passengers yesterday very happy to be in a 92 and not a 225 or any Puma variant. The dislike of the Super Puma fleet has been going in since before the REDL and the 225 ditchings / fatal accident. Passengers have never liked flying in them. In spite of the window size, they have always felt claustrophobic and unsafe.

Its a sad indictment on our industry that the helicopter operators have been so poor at communicating the safety record.

I don't know where you fly but do you routinely brief your pax that in the event of loss of MRGB lube you will have to ditch, even if the sea state (and temperature) mean survival is unlikely?

shame we have to keep using pax as crash test dummies and wait for deaths to drive improvements.

SASless - that is exactly the point.

Every single heavy helicopter ever used in the NS sea has gone in the water somewhere due to gearbox issues of one form or another -

Wessex-Chinook-S61-L2-225-S92... and if I have missed any then I'm sure they probably did too.

The industry has decided this happens too often - I agree - but wringing our hands, banning pumas or forming committees isn't going to stop it happening again.

What do the Puma/S92 engineers on this forum think can be done to minimise the likelyhood of this happening again (on a regular basis)

Maybe it's just not possible to build a heavy (-ish) helicopter than can stand the strain of routine day-out day for many years in N Sea type ops without getting a severe mechanical failure

Heathrow Harry. Tell that to Boeing. When the 234 was introduced to the North Sea they thought that the years and millions of hours in military service would mean that just flying to/from platforms would be a coast.
They were horrified when they realised what punishment the aircraft was taking.

Like dozens before. And dozens to come.

What is a bit special (and disconcerting) about this case (leaving aside all childish hysteria just because there is a video existing of the final moments) is that it possibly happened with little to zero warning (from a tech perspective).

If it turns out it was a failure of the epicyclic and if it turns out this can happen without any prior indications/chips it will take a lot of time to make sure (and prove) a redesigned epicyclic will definitely cure this issue. We are surely talking >>1Year, rather >2 years. By then it might indeed be obsolete, being considered an 'old' helicopter. Therefore if it turns out to have been an unpredictable epicyclic failure which led to the separation of the Rotor it would probably be indeed the (obviously frantically hoped for by some for various reasons -it is interesting to see which Country the most vocal are coming from :suspect:, I had hoped we were over that) end of the 225.

I'm sure it is
How did the inspection routines change from military to civilian service? How did the usage of the aircraft (MAUM, high cruise speeds etc) differ from the military flight regimes?
I suspect the answers to that cost money in terms of increased servicing, reduced TBOs and accepting a weight penalty (at the expense of passenger/mile costs) to ensure robust engineering in the first place.

The 'race to the bottom' often quoted on this forum regarding offshore ops has a lot to answer for - not directly so that one could take legal action, but indirectly by shaving margins off the operating costs whilst generating enormous profits to keep the stock exchange and the investors sweet.

Offshore and military aircraft fly out at MAUW at high speed. Military aircraft fly back empty.

Helog were (ab)using their Pumas for many years in logging.
I think the problem nowadays is with the suppliers and with the EASA focusing mainly on if the paperwork is right all else must be fine.

Sorry, just an engineer, not even aero.
So there are components which "must not fail" - over their entire service life ... which is determined ... how?
One would hope that, for these parts, they would be periodically replaced so that the used ones can be analysed (metallography) while looking for any sign of accelerated degradation?

Fareastdriver and Crab@SaaAviation

In the case of the BV234LR (civil Chinook), Boeing were told when they were ordered that we would operate them at VNO and at least 90% MAUW for around 150 hours / month. Boeing obviously didn't believe it, and we ended up with over 1000 lbs of reinforcing on each airframe as the build was clearly not up to that task. Clearly all their military operating experience did not read across to the operational pattern of the civil world. And for what it is worth they continued to operate on the Norwegian side of the North Sea long after they were withdrawn on the UK side.

That's the better idea, and who pays for this analysis program? If one watches how margins get pinched all over industry, someone in a board room stands up and says "that's a cost center that never produces revenue" and doesn't get the clu until the cost of damages spikes... which I guess is all part of the infamous risk calculus.

The BV234 is perhaps a red herring. Its withdrawal from the UKCS was exclusively down to the customer, Shell, who had chosen the BV234 to try to save money by flying direct to the big Brent and adjacent platforms (avoiding the Shetlands), then rolled over to keep the bears happy rather than try to justify the BV234 was safe after the accident.

Sensationalism and fear win over mathematics again?

Never Fretter

Actually the ultimate rationale for the withdrawal of the Shell Chinooks was the task they were doing was not what they were procured for, and Shell wanted out of a contract that had few break opportunities (and all expensive). The idea originally was an out and back trip to the ESB changing over 44 workers at a time, but in the end Shell working practices couldn't make that work and the Chinooks were doing two or three stops per rotation, swapping around 15 to 20 guys per stop, except for the Auk platform which was on its own. Using that beast as a shuttle was never going to be economic, made worse by the need then to refuel offshore. And something not mentioned here yet was the fact that Shell were using it to transport their contractor staff, the Shell employees not being happy with the high amplitude low-frequency vibration level (blade slap downwash onto the top of the fuselage) and discomfort of the really short seating pitch. Most Shell staff rotated through Sumburgh on smaller types and then fixed wing.

The true fact of the matter is, the price of oil right now allows the 225 to sit for a period of time without the oil companies getting too worked up. If the price were to start sky rocketing again we would have a different story on our hands.

The big oil companies have been pushing the operators to the brink of bankruptcy (some beyond the brink) due to the "downturn" .... Hopefully the operators will now have enough Gull to get some pay back!

At time of certification an evaluation is done to determine which parts are critical. Obviously main hub and blades main shaft. Less obvious are things that will not immediately be catastrophic due to redundancy or even partial detectable fail modes. Planet would normally be in this category as there are several and initially the chips would come before total box failure.
Next is to determine fatigue life by test usually until failure or acceptable margin. It is an expertise all on its own.
The parts replaced should not actually show fatigue damage or else not enough margin was used. The damage is in the molecular crystalline structure long before crack formation.


At