Originally Posted by
JoeCool88
As we all know it was the same crack in a second stage planet gear on G-REDL on 01.04.2009 and LN-OJF on 29.04.2016, which caused the MR to separate. After all the measures taken, like reduction of the MGB TBO to roughly one third of the initial TBO, installation of another mag plug, flight ban on one type of planet gear etc etc, the 225 could be considered as safe for flight (again), imho. Especially the more frequent scheduled MGB removals drive the costs per flight hours, but who cares.
However, after thousands of engineer hours and millions of Euros for the regarding technical investigation, the reason why a crack (twice) could propagate inside the gear rim, undetected by e. g. HUMS and the classical methods like mag plug and filter, remains still unknown. Strange, isn't it?
There is quite a bit more to this story. Airbus announced in September 2019 that they had determined the root cause, but as far as I am aware, has still never released any of this information into the public domain. There may be many reasons for not releasing this information, but none of them bode well for Airbus, as secrecy in the realm of accident investigation is a dangerous path to tread and may result in the unintended consequence of challenging their overall credibility.
AIRBUS HELICOPTERS FINDS ROOT CAUSE OF THE TUROY H225 CRASH | OGPNetwork
OGP NETWORK OIL GAS & POWER LATEST NEWS AIRBUS HELICOPTERS FINDS ROOT CAUSE OF THE TUROY H225 CRASH
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OGP Network
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September 13, 2019 On April 29, 2016, one H225 Super Puma helicopter operated by CHC Helicopter, en route from Gulfaks B to Bergen, went down close to the small island of Turoy, west of Bergen, Norway. All 13 occupants of the heavy-twin, two pilots and eleven oilfield staff died within the accident after the primary rotor separated from the plane at 2,000ft. The lack of the primary rotor in flight is essentially the most dramatic accident that may occur to a helicopter. There are not any phrases to explain it.
The UK journal Flight Global reported that Airbus Helicopters has recognized the basis explanation for the primary gearbox (MGB) failure behind the deadly 2016 crash of an H225 in Norway. In its last report in July 2018, Norwegian investigators decided second-stage planet gear within the MGB’s epicyclic module had failed as a result of sub-surface cracking and fracture of a bearing race. However, they have been unable to say what had triggered the occasion.
“The investigation has proven that the mix of fabric properties, floor remedy, design, operational loading surroundings and particles gave rise to a failure mode which was not beforehand anticipated or assessed,” the report says.
But the airframer has continued its personal evaluation of the occasion, says H225 programme director Michel Macia, resulting in identification of the basis trigger and a profitable replication of the failure in testing. That work has been externally validated, he says. Findings from that effort have been subsequently shared with Norway’s SHT accident investigation physique, regulators together with the European Union Aviation Safety Agency, and different producers, says Macia.
“Everyone now is aware of that the basis trigger is known and has been reproduced,” says Macia. Although he declines to element the failure, he says the security obstacles put in place to allow the H225 to return to service take care of the underlying difficulty. These measures embrace a heightened inspection regime, shorter life limits on elements and – considerably – the exclusion of one of many two totally different bearing designs used on the helicopter.
The H225 and the associated AS332 L2 have been grounded for 4 months following the crash, and though each at the moment are cleared for service, they’ve but to be introduced again to operation within the North Sea area for offshore transport. While that’s largely as a result of overcapacity within the sector, there stays vital opposition from the oil and fuel workforce to the H225.
But Airbus Helicopters chief government Bruno Even nonetheless believes the rotorcraft could make a comeback within the North Sea and says the plane wants time to realize acceptance.
“We are doing all that we’re capable of do, however ultimately, it’s the buyer who has to determine.”
The UK Civil Aviation Authority says its place on the H225 has not modified and it has but to obtain an software from an operator to renew H225 passenger flights within the nation.
(Source: Flight Global – Image: Aibn/Super Puma rotor on Turoy Island)