FH1100 Pilot
Then, if the plaintiff's attorney is smart, he'll ask: "Are there NO other places that oil might leak out of the transmission? For instance, does the transmission have input seals for the engine driveshafts?"
SAC: "Yes, of course."
ATTY: "I see. And is there an oil seal up where the mast comes out of the transmission?"
SAC: "Yes, of course."
ATTY: "Is there an oil seal where the tail rotor drive shaft comes out of the transmission?"
SAC: "Yes, of course."
ATTY: "So that's four oil seals so far...which are used when you want to keep oil *inside* something, is that correct?"
SAC: "Yes, of course."
ATTY: "And there's no way on God's green earth that oil under pressure could even possibly leak out from those locations?"
SAC: "No. No way. Those seals would never fail. Seals don't fail."
ATTY: "Oh, they don't, huh? Well, humour me for a moment, please. IF a seal did fail, could all of the transmission oil be pumped overboard and lost?"
SAC: "Well...yes...theoretically...if you want to split hairs."
ATTY: "Well that is what we attorneys do best, sir! But thank you. But we'll come back to your seals-that-never-fail in a bit. Meantime, does the S-92 have an externally-mounted oil filter"
SAC: "Yes, yes of course."
ATTY: "And tell the court, please, how is that filter attached to the main structure of the gearbox?"
SAC: "Well, we use studs to secure the filter housing to the transmission."
ATTY: "Ah yes, the infamous studs. And is there an oil seal of some sort there as well?"
SAC: "Yes, of course."
And the jury will see that there are PLENTY of places where oil might possibly leak out of an S-92 transmission, not just the oil cooler lines as Sikorsky claimed. The jury will likely conclude that the manufacturer was either negligent in their thinking, OR the FAA was "in bed" with them on this issue. How or why the FAA allowed Sikorsky to get away with that wacky (and insufficient IMHO) isolate-the-lines-to-the-cooler system is something they're probably worried about right now. I can imagine the FAA Administrator at his desk, cradling his head in his hands and going, "Holy Geez, did we REALLY approve that cockamamie setup? Why...WHY?!"
Using your courtroom scenario above, you could of course remove SAC and insert Eurocopter, AW, Bell, MDHi etc., as all transmissions have seals and oil filter bowls/access covers and no OEM would be able to offer a 100% guarantee that oil could not leak out of their transmissions under any circumstances......EVER!
So we come back to acceptable risk and probability and a certification process for ALL OEM’s based on data submission and in-service experience, which is surely how the S-92 and every other platform flying PAX was certified.
The world’s Offshore O&G helicopter fleet clocks up around 1.5 million flight hours per annum and as each helicopter main transmission has a multitude of oil seals, that’s a gargantuan amount of oil seal and static filter bowl hours being clocked up every year and yet with no apparent headline grabbing failures that I read of, so surely this would suggest that in the industry
“such failures are extremely remote”, does it not?
Only last year we had a main transmission disintegrate in flight leaving the crew and PAX with no chance of survival whatsoever, but I don’t see any posts on this thread demanding the guilty OEM’s head on a plate as appears to be the case for a number of you on this thread.
Since replacing the studs, I’m not aware (I stand to be corrected) of any further incidences on this platform type whereby the MRGB oil has leaked out at the same location, so surely the AD resolved the issue. Had the S-92 been installed with steel studs from day one, then it is likely that this thread would never have been started.
Dangermouse.
I cannot speak for the AW139 and AW101, but the EC225 does not have a 30-minute Run-Dry Main Transmission. I do concede however, that it does have an alternate lubrication/cooling system in the event of total loss of oil.
By far the biggest cause of accidents in the rotary industry is CFIT/CFIT(W), but I don’t see some of the most vocal on this thread demanding of all OEM’s that each and every platform operating in the Public Transport category be fitted with an EGPWS/TAWS/AVAD type system (irrespective of their age and with immediate effect), the installation of which would save far more lives than a true 30-minute Run-Dry compliant transmission would, would it not?
As I’ve stated before, I’ve no doubt that when the final report is issued, there will be many questions and much soul searching on all sides in this tragic accident.
Safe flying.