Bristow emergency landing
 

There doesn't seem to be a date on that story. Can anyone paste in the full story?

Don't have the full story, but digging a bit deeper gives this as date:

AIBN News bulletin
 

The essence of a brief statement last night from the NSIA (previously AIBN) is something like this:

On Friday the 25. of September the crew of a S-92A, LN-ONQ on a return flight to Sola from West Elara, got warning that the oil pressure in the MGB had dropped. Later , as the oil temperature started rising, the crew transmitted a MAYDAY call and continued the descent to 200'. They prepared for a ditching if the pressure drop should continue that far. The landing at Sola was uneventful and they were escorted to parking by the emergency services.

The AIBN arrived the same evening and started their investigation. No causes for the event has so far been establised.

Anyone have any more info?

Presume they didnt goto MAN COOL so makes sense the temp increased.

92
 

https://verticalmag.com/news/norwegi...tion-incident/

Amazingly lucky. Once again reminding that S92A gearbox is a deathtrap...it cannot actually run dry. Recall their Part 29 certification run-dry "extremely remote" clause basis was on the oil leak occurring in the cooler circuit, and the mitigation was to bypass the cooler loop.

If you lose oil from the MGB itself for any other reason (i.e. filter mount like Cougar, or literally any other main case penetration) then you're hosed.

8 minutes.

Seems odd that just losing 4 litres out of the normal 30 litres should cause such a nasty problem?

I suspect the oil leak was a consequence rather than the cause.

Mechanical problem in the input module, leading to lots of heat being generated, leading to oil seals between modules being compromised, as well as heating up the MGB oil.

Only speculation on my part.

That makes sense Apate but raises the question of the design of the input module.

Death trap? What rubbish. Turned out alright didnt it. They had a caution, not a warning, the OIL OUT is land immediately, they obviously didnt have that and they had sufficient pressure to continue flight to land.

Simply because this particular incident didn't lead to an actual full oil-out condition since they were already on approach (it would only have been a matter of time with the leak as described) doesn't change the issue that the S92A MGB cannot operate without oil for more than approximately 8 minutes.

The fact that it holds Part 29 certification despite this is mind boggling, particularity since there have been enough incidents of leaks from the MGB case to make the "extremely remote" 10^−7 occurrence clause statistical nonsense.

Weren't they on their way back? So it could have been losing oil for the previous 2 hours or so... it was hardly a catastrophic event.

The gearbox has a good record.

over a million hours in the sky, not bad for a deathtrap.

What planet do you live on?

I'm sure that's comforting to the families of the 17 victims of Cougar 91, or the luckier CHC crew the year before.

But its still an order of magnitude below the number of hours required (10^7) without a single loss of MGB case lube incident to verify its certification loophole basis.

If the gearbox is so good, how come a loss of between 10 and 15% of the oil led to such massive overheating of the input module? 214 degrees C!

The cougar crew unfortunately didnt help that situation and a false understanding led them to continue flying.

Because a drop in pressure triggers the cooler bypass... they could have chosen to reverse the bypass and cool the oil, they obviously knew where the issue was and it wasnt the cooler.

so if the problem isn't the cooler, why not reverse the bypass? If the leak is in the no 1 input module its going to keep leaking regardless isn't it? Why risk overheating the engine inputs as well?

Not a 92 driver so just keen to understand.

I think the purpose of the bypass is to save as much oil as possible in the event of a leak. Hot oil is better than no oil. I can’t remember what the capacity of the cooler is, I’m on leave but it takes a fair amount.