Oil platform helicopter crashes in Norway; 13 dead-Final Report

a reply to: JIMC5499

It's that "probably" that makes you nervous though. Yeah, you probably could have, but that's a long swim if it crapped out.

a reply to: Zaphod58

That's why we didn't try. The problem with main gear boxes is that you have to completely disassemble them to totally inspect them. Changing them out is the hardest most labor intensive job that there is on a helo. I think that is what needs to be done if they are going to keep flying this type. Tear the gearbox down, Magnaflux all of the gears, replace any with defects and reassemble.

a reply to: JIMC5499

They need to do something and do it fast. This thing is a death trap in this role.

The European Aviation Safety Agency says that although the investigation into the root cause of the accident – in which 13 passengers and crew lost their lives – remains ongoing, “the partial information available so far indicate[s] in-flight separation of the main rotor hub from the main gearbox”.

Footage of the incident clearly shows the main rotor assembly spinning to earth having detached from the rest of helicopter.

In its airworthiness directive, EASA says that prior to the next flight operators must check the correct installation of the main gearbox suspension bars; examine the chip detectors and oil filters for the presence of metallic particles; and download data from the vibration health monitoring system for threshold exceedances.

www.flightglobal.com...

I wonder if a borescope inspection on the main gear box would be any help?

a reply to: JIMC5499

I can see where it should, but I could see where it wouldn't too.

Apparently parts related to the main gearbox have yet to be found. Investigators have resumed the search for them and have said they'll look as long as necessary to find them.

CHC, who operated the crashed helicopter has filed Chapter 11 bankruptcy.

Investigators say that there are no indications that crew actions or a fatigue failure caused the accident. They said that it was a normal flight, until a catastrophic situation occurred in 1-2 seconds, leading to the rotor separating. They're focusing on the main rotor suspension bar assembly, main gearbox, and main rotor head, but several key pieces are still missing.

a reply to: Zaphod58

Aaargh, this is really bad news because the last I heard was that although all Super Pumas are grounded in the UK due to a CAA ban, they have been given the green light by Airbus to resume flights worldwide.

That kind of structural fault could easily happen again in other planes, I would think?
It was Iain Stuart's funeral yesterday (the Scottish victim). You can't help but think of the two kids he left behind. It's such a tragic and needless death.

a reply to: beansidhe

They've issued an AD to check the gearboxes, which currently is all they can do. As for the flight ban, Airbus can say they lift it all they want but until the CAA and EASA lift it they're not going anywhere.

a reply to: Zaphod58

I can't see that happening (fingers crossed).
Why are they saying to check the gearboxes when the problem was in the rotor coming off?

ETA: Scrub that daft question, they're connected together if I'm reading your earlier posts right.

a reply to: beansidhe

Yep. After assembly it becomes essentially one unit. Most of the problems they've had have come from the gearbox portion of the system.

Investigators are focusing on three possibilities. Failure of the epicyclic module, lift strut or suspension bar attachment, or failure of the Main Gear Box conical housing. They're attempting to narrow down areas to search for missing pieces and will resume looking for them next month.


www.flightglobal.com...

a reply to: Zaphod58

wow that big bad oil is really bad for people and the environment!

European regulators have ordered all H225 and AS332 L2 helicopters grounded. Of the three components being looked at by investigators, evidence of fatigue and surface degradation were found on the surface of one of the secondary planetary gears in the epicyclic module.

Current inspection methods will not find evidence of this occurring.

www.flightglobal.com...

a reply to: Zaphod58

was it the oil company fault?

Investigators are reiterating that the secondary planet gear failed, and failed in a manner that the health monitoring system failed to detect. They found sub surface cracks during a CT scan of the gear, that should have resulted in the HUMS or oil sample testing finding metal shavings in the oil system, but nothing was found since it was installed in January of this year by either. The cracks also apparently propagated starting from the outside portion of the gear, and went inward, instead of starting on the inner portion and heading towards the outer edge.

The gearbox in question was involved in a road accident during shipping. It was inspected and cleared for installation afterwards. Investigators are trying to determine if that played a role in the incident.

www.flightglobal.com...

originally posted by: Zaphod58
CHC, who operated the crashed helicopter has filed Chapter 11 bankruptcy.

I worked for CHC Scotia for over a year.

CHC Scotia were so underfunded in their operations they were still using 16bit software with a Borland SQL backend to run their maintenance system.
They couldn't roll out Windows 7 x64 to the company because they had no solution for getting the version of Borland SQL software compatible with a 64 bit OS.
I was so shocked by how little money was being spent on keeping maintenance systems operating efficiently. They only spent about 1% of their turnover on IT systems which included maintenance logging.
It doesn't surprise me that they are filing for bankruptcy.

a reply to: Zaphod58

I wonder if this is going to play out like the DC-10 turbine wheel failures back in the 80's. Imperfections in the forgings causing failures in flight. Google Sioux City Iowa crash for info.