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

a reply to: JIMC5499

I wouldn't be surprised if it was.

Although thinking about it, I would expect that to crack from the inside out, not the outside in.

a reply to: Zaphod58

It all depends on where the imperfections are and the way the loads are placed on the parts. It also depends on the grain boundaries of the metal and how the parts were finished. (heat treating, nitriding etc.)

The fallout continues. Korea has grounded its fleet of KUH-1 Surion helicopters. They are based on the H225/AS332 designs, but were developed and built in Korea with the help of Airbus. Of The 52 in service, 30 need to have their gearbox replaced. Airbus helicopters has sent out an emergency alert service bulletin calling for the replacement of some planetary gears. Airbus will reimburse the Korean government for the expense.

www.flightglobal.com...

The flight ban put in place by the EASA has been lifted, but the UK and Norwegian bans remain in place.

Airbus has called for replacing one of the two planetary gear configurations. They didn't specify which manufacturer or configuration, but they found one has higher operating stress, which results in more spalling events. They've also reduced time between inspections of the chip detector and oil filters to 10 hours.

www.flightglobal.com...

originally posted by: Zaphod58
They've also reduced time between inspections of the chip detector and oil filters to 10 hours.
www.flightglobal.com...

Their mechanics are going to love that. That pretty much makes pulling chip detectors part of the daily inspection. If their chip detectors are anything like Sikorsky's, they can be a pain in the ass.

Airbus Helicopters met with regulators to discuss a path to return the H225 helicopters to service. Both Norway and the UK have continued the grounding order issued after the crash.

Airbus Helicopters and officials from the Norwegian and UK civil aviation regulators met earlier this week to discuss the return-to-service path for the H225, sources indicate.

The 11t-class helicopter, and the related AS332 L2, remains grounded by the authorities in those two countries, despite European regulators lifting a ban imposed after a fatal accident in April 2016 in which 13 people were killed.

No details of the discussions have been revealed, however.

www.flightglobal.com...

a reply to: JIMC5499

Sikorsky grounded all their S92 helicopters the other day, after one gouged into a rig as it landed:

Helicopter manufacturer Sikorsky has grounded all S92 aircraft worldwide for safety checks following an incident on a North Sea platform.
Operators were instructed to carry out the checks immediately, centred on tail rotors. Many of the inspections were completed by Tuesday afternoon. The Air Accidents Investigation Branch (AAIB) is investigating an incident on the West Franklin Platform which happened last month. An S92 experienced a technical fault when it was coming in to land. It left "significant gouge marks" on the deck of the platform.

BBC NE, Orkney and Shetland

Better safe than sorry, I guess.

a reply to: beansidhe

www.abovetopsecret.com...

a reply to: JIMC5499



I figured you would all already know about it, about 3 minutes after I wrote that.

The one year anniversary sees another report, and still no definitive cause. They believe that the planetary gear came apart, but not why.

Two bearing companies were identified as making the gear, and investigators found that one of them was three times more susceptible to spalling than the gear made by the other company. They found 22 incidents of spalling between 2001 and 2016,compared to 7 in the same time period by gears made by the other company.

www.flightglobal.com...

Once operators prove they have the required processes, training, and equipment in place, then Norway and the UK will allow them to start flying the Super Puma again.

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Era Group announced a $117M write down in the latest quarter. This was caused by the latest appraisal of their 9 H225 Super Puma helicopters. They have been grounded since the Norway crash, and were valued at $4M each. They should have been valued over $15M.

www.flightglobal.com...

Investigators have confirmed that the second planetary gear failure was the cause of the rotor separation. They're recommending that Airbus redesign the gearbox and testing process. They also say that both Airbus and the EASA failed to learn the proper lessons after a similar crash in 2009, caused by the same type of gear.

They still don't know the ultimate cause of the fatigue crack, but they did confirm that neither the crew or maintenence did anything wrong. Unlike previous failures of similar gears, there was very little spalling to leave shavings in the detector system. Short of pulling the gearbox and performing an in depth inspection of the system, there was no way to know anything was wrong.

www.flightglobal.com...

originally posted by: Zaphod58
As the aircraft approached the shore, the main rotor apparently separated and it fell 2100 feet in 10 seconds, hitting a rock near shore and exploding. It's the first accident for Norway since 1997.

Yikes!

I've heard of helicopters having a "Jesus nut." (So called because, if it fails, you're going to meet Jesus.) Would this be a case of that separating?

a reply to: AndyFromMichigan

It appears that the second planetary gear came apart, destroying the gearbox that holds and turns the rotor. The rotor separated, they rolled almost 360 degrees left, and fell almost 90 degrees nose down in a ballistic track.

a reply to: AndyFromMichigan

This is similar to the gear that failed.

I worked in the oil industry in the states on and off from the mid 70's to late 90's. I mostly flew on Bell 212s and 412s. Sikorsky helicopters were used for awhile, which are prone to failures, also. I heard about Puma crashes but never flew on one. There was one Sikorsky that had to set down in the water, get everyone out and fly back to base because one of the engines seized.

Glad I wasn't on it. A boat was launched to pick up personnel that were in the water.

a reply to: eManym

The Puma is a crash looking for a place to happen. The accident and failure rate is bad enough that even after the grounding was lifted companies that operate them can't unload them fast enough, if they can even unload them. Most of them are just parking them and looking at other options.

Without giving details, Airbus has confirmed that they identified the cause of the gear failure and have replicated it under test conditions. They also say that the measures put in place after the crash will prevent another occurrence.

www.flightglobal.com...