212man
I'm happy to be corrected as the history of failed vespel spline product improvements is rather, erm, 'complex', but I know we can agree that the Norsk case was low oil pressure.
The checklist linked to earlier today was posted by HC in April 2005 just after the Norsk incident. I assume it is an earlier version to yours (repeated below).
Quote:
If the MGB OIL PRES warning or the MGB OIL PRES caution and any of the following secondary indications of gearbox
failure are observed:
MGB oil pressure below 5 psi
Smoke or fumes in the cabin
Any subsequent hydraulic system failure
Progressively increasing power required to maintain flight
Unusual vibrations or noises.
6. Land immediately.
However is your issue pre or post the Norsk event?
I only ask because this could reinforce the point of Sikorsky
tinkering with the RFM (to change "If MGB oil pressure continues to decrease" to "MGB oil pressure below 5 psi" to avoid reasons to ditch (in response to less critical gearbox failure modes)
prior to the Broome & Newfie events.
I can see how some crews, reading an evolving RFM, without the benefit of frank insight to the S-92A service experience might have
assumed this was asign of greater confidence in the MGB, not as was the case, less.
But if neither of the two Shell events were low oil pressure, what triggered the landings into jungle clearings?
I didn't think it was smoke in the cockpit from the leaking seals of the input module which overheating due to churning. But perhaps it was. Certainly with the checklist above, high oil temperature is not a reason to land immediately, while the sounds of a potentially immenent gearbox failure are. Hardly a design sucess either way.
HC makes a good point on the tolerance of MGB pressure gauges and the difficult call crews have had to make.
It would also be nice to hear if anyone is prepared to comment on Shell Management's claims the S-92A was 'non-preferred' for a time.http://www.pprune.org/rotorheads/163...ml#post6043644
I'm waiting for feedback from my own sources in Shell on that one.