SAS, I'm not sure if you try to be obtuse and argumentative or if it just comes naturally to you. Either way, your posts are tiresome.
But okay SAS, you're right: I'm such an idiot. I absolutely got it wrong. It wasn't nine minutes from loss of transmission oil to transmission failure - it was
eleven minutes. And it wasn't nine minutes that the CHI crew got after they noticed a low transmission gearbox pressure to the time their gearbox failed, it was
ten minutes. Silly, silly me.
Mea culpa, mea culpa, you dick.
Look, I'll play your silly game and make it easy on you. Which one of the following statements is not true?
1.
Trans ran dry.
(True/False)
2.
Pilots believed that they had "30-minute run-dry" capability as per FAR Part 29.
(True/False)
3.
Sikorsky knew it would only last (edited) 11 minutes with no oil at all.
(True/False)
4.
Transmission (tail rotor drive) came apart (edited) 10 minutes into the emergency.
(True/False
5.
Pilots screwed up emergency landing.
(True/False)
6.
Everybody died except one pax.
(True/False)
Here is the synopsis from the Transport Canada report on the accident:
On 12 March 2009, at 0917 Newfoundland and Labrador daylight time, a Cougar Helicopters' Sikorsky S-92A (registration C-GZCH, serial number 920048), operated as Cougar 91 (CHI91), departed St. John's International Airport, Newfoundland and Labrador, with 16 passengers and 2 flight crew, to the Hibernia oil production platform.
At approximately 0945, 13 minutes after levelling off at a flight-planned altitude of 9000 feet above sea level (asl), a main gearbox oil pressure warning light illuminated. The helicopter was about 54 nautical miles from the St. John's International Airport. The flight crew declared an emergency, began a descent, and diverted back towards St. John's. The crew descended to, and levelled off at, 800 feet asl on a heading of 293° Magnetic with an airspeed of 133 knots.
At 0955, approximately 35 nautical miles from St. John's, the crew reported that they were ditching. Less than 1 minute later, the helicopter struck the water in a slight right-bank, nose-high attitude, with low speed and a high rate of descent. The fuselage was severely compromised and sank quickly in 169 metres of water. One passenger survived with serious injuries and was rescued approximately 1 hour and 20 minutes after the accident. The other 17 occupants of the helicopter died of drowning. There were no signals detected from either the emergency locator transmitter or the personal locator beacons worn by the occupants of the helicopter.
Bob Denny, here is the link to the Transport Canada TSB report:
Transportation Safety Board of Canada - Aviation Investigation Report A09A0016
To save time, I bid you to please refer to Section 1.18.5 S-92A MGB Certification.
There you'll read about how FAR 29.927(c)(1) calls for a helicopter transmission to run for 30 minutes after the loss of lubricating oil.
Sikorsky drained all the oil out of an S-92 gearbox and it ran for eleven minutes until it came apart.
But wait! Like I said, there's a loophole. The FAA permits manufacturers to forego that "30-minute run-dry capability" (as it's informally known in the industry) if such incidences of total loss of oil are "extremely remote." And while extremely-remote is not specifically defined in the 29.927(c)(1) it is generally considered to be one in 10 to the seventh power to 10 to the ninth power. Gee, that's pretty remote!
In Section 1.18.5 of the TSB report you'll read about how Sikorsky convinced the FAA that the only real failure of the trans would be the lines going to and from the transmission oil cooler. Yes, yes, sounds good. Never mind the external oil filter (oh, those never leak!) or the seals on things like accesssory drives (e.g. the generator) or the tail rotor drive shaft or the seals on the two input drive shafts from the engines. Nope, none of those would never leak either!
So Sikorsky simply came up with a means of bypassing the transmission oil cooler. Once the pilots got the "Low Trans G/B Press" caption they had
five seconds to activate the emergency bypass, or all of the transmission oil might have been lost. Problem solved! With the cooler isolated and "some" oil lost, the trans oil temp would probably climb up into the red, but hey, at least you'd have some oil circulating around! The trans can run for a long time with hot oil. It just can't run for 30-minutes with
no oil.
Handshakes were made and all agreed that no transmission would fail in that way in 10 to the seventh power of flight time. Bing- certified! Aren't their faces red now! Well...no...but they ought to be.
And so that's what happened. A big sun gear in the transmission failed. The drive to the tail rotor disintegrated - like hot melted plastic. While the transmission did not explode or sieze, it was definitely coming apart and would not have lasted much longer with all that molten metal flinging around inside it. But it didn't matter. Flight tests showed that the S-92 was incapable of level flight after a tail rotor failure. (TSB Section 1.18.1.4) Either way, that ship was going down.
In this case, the PF screwed up the auto and pretty much leveled and cushioned at 90 feet or so. Oops! It was a long way to fall.
SASless may tell you I've got things wrong with my description of this accident, but he won't provide a reference. I do not have it wrong.
He is mistaken. But he's old (and possibly senile) and apparently not a pilot anymore, so his opinions cannot be confidently relied upon.
In any case, the peculiar CHS S-92 accident should not deter you from flying up an altitude higher than 500' agl. Me? I agree with guys like Shawn Coyle. And if he says to fly high, that should be good enough for the rest of us too.