Helicopter crash off the coast of Newfoundland - 18 aboard, March 2009

[S92mech]

This is from the S-92 RFM

Land immediately — Continued flight may not be possible. Ditching or landing in hazardous terrain is preferable to continuing flight.

Land as soon as possible — Land at the nearest site where a safe landing can be accomplished.

Land as soon as practical — Extended flight is not recommended. Landing site and duration of flight are at the pilot’s discretion.

[ttt_mtt]

to land safe or not

if an emergency procedure says to LASAP before Land/Ditch we should not wait for the last signal for Ditching over sea quite far away to shore.

Because still we have a chance for a safe landing why should we wait for to Ditch(which not ensure us a safe approach or controllable helo)

for example

can you control a 212 in a dual hydraulic emergency

so will you go on to fly with a hydraulic or make safe landing to sea

[zalt]

Helicopter designers need to understand that Land Immediately does not automatically mean passengers and crew are protected if that results in, say, a ditching.

Committee hears tale of belated rescue - Local - News - The Telegram

[212man]

Zalt,
I think they do understand that which is why the requirement is only stipulated for extreme cases. Ditching and losing half the pax and crew is a really bad thing, however staying airborne and having a structural failure because you are on fire, or having the rotor stop as the MGB seizes, is probably going to result in a 100% loss. What would you recomend if writing the checklist?

[SASless]

Land Immediately.....what is ambiguous about that?

Ditch.....what is the "time" element of that directive? Immediately....delay as needed to organize SAR, divert to nearest assistance (boat, vessel, rig, point of land) or make your call and confirm someone knows your location, intentions, and numbers of persons aboard?

212man raises a good question....it depends upon how you feel about gambling with people's lives! One way you kill some.....the other way you may not kill any....or kill everyone. If you decide using probability....you continue on and roll the dice on an all or nothing wager. If you decide rationally....one could decide to risk as few as possible.

The other question that does not get argued as it should....is when do you stop flying due to the hazards beneath you that make landing out/ditching such a serious gamble? Are we ignoring the patently obivious by putting ourselves in that position? Should we operate in sea states that exceed the certification of the emergency flotation? Should we operate in temperatures (ambient and water) that present a risk of death that exceeds the SAR response time factored for successfully locating and rescuing from an in-water situation?

Get a grip on those questions then talk to me about equipment, training, physical standards, and the rest.

I don't want to hear about "economical issues, we cannot do business if we don't......and that response. Let's put lives first and economics last. Last time I checked we are not fighting a war but rather are in the oil production business. What price/value/worth do we put on human life in this business?

[SASless]

Toys firmly tossed!

Nick is anything but ambiguous. He is a well known long time Professional with a great reputation and proven ability.

Sox.... pose your questions in a manner that seeks information or begs a professional response would you? Save the personal attacks for Facebook.

Nick....slamming the door leaves the rest of us without a way to understand the issues. Reminding, in great detail, how the testiing was done would be the way to move this discussion along in a proper manner.

Throw the facts out and clear the air (once again I know....) and put Sox's allegations to rest. Ignore him as you wish....but remember the rest of us who appreciate your input here at PPrune.

[Brian Abraham]

The other question that does not get argued as it should....is when do you stop flying due to the hazards beneath you that make landing out/ditching such a serious gamble? Are we ignoring the patently obivious by putting ourselves in that position? Should we operate in sea states that exceed the certification of the emergency flotation?

SAS raises a very good point that I've oft thought about. How does one go about doing the land immediately thing when flying on top of a fog layer in which the viz is zilch, dead calm water, maybe at night as well. Something you train for? Who of the crew does what in such an event? Mechanics of carrying it out?

So much of what is done in the oil industry would not meet the standards to which airlines operate. Wonder if "land immediately" features in airline checklists.

[riff_raff]

Maybe NickLappos can answer a question for me regarding the design of the S-92 MRGB lube oil filter housing. I'm not a transmission design expert, but one thing I do know is that with a single path system or component that is flight critical (like the lube oil filter housing), it should be designed with fault tolerance in all aspects. That would include the fastening system holding it in place.

Looking at the photo linked below, it would appear that even though proper fault tolerant design practice was followed regarding using multiple fasteners with dual locking features, the spacing and position of the fasteners may have been deficient. With only three widely spaced fasteners holding that filter housing in place, it appears as though the failure of just one fastener, combined with the force created by oil pressure acting against the large surface area of the filter housing, would be more than enough to dislodge the housing. In other words, this housing design does not appear to have the level of fault tolerance that would normally be required of a flight critical component. This type of flange failure is not unknown, and is something that would be checked for in a thorough FMEA.

Do you know if the filter housing was part of a critical items list? And if so, was this failure mode considered in the FMEA?

Thanks in advance for any insight you might be able to provide. And I apologize if this question was answered in an earlier post, but there's just too many to go back through.

http://www.flightglobal.com/assets/g...x?ItemID=29667

riff_raff

[NickLappos]

Sasless, were I to post the PM that sox6 sent me, you would be very angry with him. I don't deal with assholes very well.

Riff_raff,
Your observations are well pointed at an important issue. With ongoing litigation, it is unwise for me to broadcast an answer. Pls PM me, if you will.
Thanks
Nick

[industry insider]

The new MGB housings have a 6 modified stud attachment to the MGB housing as well as a 6 secondary stud attacment for bowl removal. The attachment to the MGB housing itself never needs to be removed. I can post a picture if you wish.

[js0987]

Brian,

To your question about landing in fog or 0/0 conditions; it is something that is often done in the simulator. Its a matter of coordinating the deceleration and descent so as to arrive at the surface with as little forward airspeed and as slow a rate of descent as possible. If you don't get the big red screen, you made it.

[SASless]

How about putting in a Sea State 6, wind blowing about 45 knots, OAT of -10, and water temp of say....+5.....assume no one gets into the raft, and SAR response time of one hour to the scene, 15 minute search to the first survivor....and 14 people in the water.....at night!

How does that play out?

[FH1100 Pilot]

Ambiguous?

I hate to jump in on this, but I have to kind of back up what Sox6 says about N. Lappos and ambiguity.

I remember reading Nick's post - the glowing report about the testing SAC did on the S-92 transmission. We can dig them up and cut-and-paste them if necessary. I remember being impressed with the numbers- of how long it ran without oil. And "without oil" was implied (by Nick) and assumed (by most of us). I'll bet most of us did not completely grasp the nature of that goofy oil cooler bypass thing - that the successful use of it was dependant upon the pilots detecting a leak in the cooler lines and doing something about it before all the juice was pumped overboard.

Flash forward. We know now that "without oil" was not the case at all. We know now that all Sikorsky did was cause (or simulate) a leak in one of the lines to the external oil cooler, and then isolate that cooler and keep on truckin', as they say.

So yes, Sox6 is right: In that regard Nick was being a little ambiguous about that test because he did not mention that Sikorsky knew that without any oil the transmission wouldn't last 10 minutes. Which was, tragically, proven in the field at a later date.

But wait. Hang on. We also know that the rules are ambiguous, aren't they? Disregarding that awkward "extremely remote" wording, we know that the rules do not call for a complete loss of all transmission oil and then 30 minutes of continued operation. Nope, the particular rule only references "a" loss of lubricant, and it doesn't specify how much lubricant must be or can be lost. There's some wriggle-room in the interpretation, and SAC used it every millimeter of it.

After Cougar, Nick was in a horrible, unenviable position (and likely still is, depending on what litigation comes out of that crash). At the time of certification, he probably really, really, really, really believed that those oil cooler lines were the "only" potential source of a leak. Hey, nobody's perfect. So even if Nick was not being totally clear or forthcoming, are we to assume he was being deliberately ambiguous or worse, dishonest? No. And I think it would be unfair to him for us to assume so.

Now Sikorsky, on the other hand...

Well... that's for the courts to decide. The real courts. Here on the internet, the PPRUNE court of popular opinion has ruled that Sikorsky fudged on that "extremely remote" stuff, and the FAA went right along with them.

[SASless]

Or.....did the FAA write a certification requirement that used the "extremely remote" standard and Sikorsky comply with that requirement?

I would suggest the industry learned a lesson out of this tragedy....at least we hope we did.

The real lesson learned is simply....Helicopters are different than airplanes.

Helicopters rely upon "transmissions" for more than mere propulsion....they are also "flight controls"....and "extremely remote" being an allowable failure is fatally flawed logic.


Finally.....when the Checklist clearly stated:
MGB Oil Pressure < 5psi.....Land Immediately!

Does it matter why one does not comply with the Checklist? Sikorsky correctly stated the action that SHOULD have been taken. It was right there in Black and White printed on the Checklist.

I would love to read the transcript of the radio exchange between the Flight Crew and their OPs while they were turning back and descending to a lower level and staying at cruise power upon leveling off. That would probably explain why they did what they did.

Anyone have a transcript of that handy?

[What Limits]

But in a risk management context, extremely remote is probably the lowest level of likelihood above zero.

Can we really afford to buy or operate aircraft that have zero likelihood of something going wrong?

Even flight critical components have a mean time between failures.

I do not wish to get into the blame game, but what we should be focusing on is the decision making by all the stakeholders in a Threat and Error Management context.

[squib66]

FH1100 Pilot - good analysis!

It is worth remembering that in some juristictions there would be more that just claims for damages. In the UK there is now a crime of corporate manslaughter, brought in to make sure big companies are accountable for their actions.

After the terrible Nimrod crash in Afganistan, which killed 3 people less that Cougar 491, ten people were publically named and shamed for failures in connection with that accident by a special inquiry. The most senior was accused of:
...a "fundamental failure of leadership" ..and that... he failed, in truth, to make safety his first priority." All ten were facing diciplinary action and possible criminal or civil charges.

That inquiry commented that:

A safety review... was a "lamentable job" which failed to identify "key dangers", he said. "Its production is a story of incompetence, complacency and cynicism. The best opportunity to prevent the accident...was tragically lost".

One wonders what could be said about the FMEA for the S-92 and the analysis that falsely concluded the critical failures that occurred would be 'extremely remote' (and in practice were anything but). One also wonders who will stand up and take responsability for the short comings in teh design

Let us also not forget that the component that failed was a simple threaded stud, that was static and not heavily loaded. If the designers failed on such simple and basic components, one must seriously question other elements of the design. In fact the studs should not have even been critical components, it was only a poor design that made them critical!

Those who are critical of the pilots for not ditching into a choppy and freezing ocean need to remember that a certification loop-hole was cynically used to avoid fixing a known inability to operate with a loss of lubrication. Thirty minutes operation who have resulted in a safe landing.

[HeliComparator]

we know that the rules do not call for a complete loss of all transmission oil and then 30 minutes of continued operation. Nope, the particular rule only references "a" loss of lubricant, and it doesn't specify how much lubricant must be or can be lost.

Its true that the rule is rather ambiguous, however the guidance material that went with it (AC 29-2C) is more specific. Use of the word "drained" is surely indicative of losing all the oil? Sorry for long quote below:

b. Procedures.
(1) Section 29.927(c) prescribes a test which is intended to demonstrate that
no hazardous failure or malfunction will occur in the event of a major rotor drive system lubrication failure. The lubrication failure should not impair the ability of the crew to continue safe operation of Category A rotorcraft for at least 30 minutes after perception of the failure by the flight crew. For Category B rotorcraft, safe operation under autorotative conditions should continue for at least 15 minutes. Near the completion of the lubrication failure test, an input torque should be applied for 15 seconds to simulate
a minimum power landing following autorotation. Some damage to rotor drive system components is acceptable after completion of the lubrication system testing. The lubrication system failure modes of interest are usually limited to failure of bearings, gears, splines, clutches, etc., of pressure lubricated transmissions and/or gearboxes. A bench test (transmission test rig) is commonly used to demonstrate compliance with this rule. Since this is a test of the capability of the residual oil in the transmission to provide limited lubrication, a critical entry condition for the test should be established.
The transmission lubricating oil should be drained while the transmission is operating at maximum normal speed and nominal cruise torque (reacted as appropriate at the main mast and tail rotor output quills). A vertical load should be applied at the mast, equal to the gross weight of the rotorcraft at 1g, and the lubricant should be at the maximum temperature limit. Upon illumination of the low oil pressure warning required by § 29.1305, reduce the input torque for Category A rotorcraft to the minimum torque necessary to sustain flight at the maximum gross weight and the most efficient flight conditions. To complete the test, apply an input torque to the transmission for approximately 25 seconds to simulate an autorotation. The last 10 seconds (of the 25 seconds) should be at the torque required for a minimum power landing. A successful demonstration may involve limited damage to the transmission, provided it is determined that the autorotative capabilities of the rotorcraft were not significantly impaired. For Category B rotorcraft, upon illumination of the low oil pressure warning light, reduce the input torque to simulate an autorotation and continue transmission operation for 15 minutes. To complete the test, apply an input torque to the transmission for approximately 15 seconds to simulate a minimum power landing. A successful demonstration may involve limited damage to the transmission provided it is
determined that the autorotative capabilities of the rotorcraft were not significantly impaired. If compliance with Category A requirements is demonstrated, Category B requirements will have been met.

So its my contention that the only way it achieved certification was through the "extremely remote" bit.

HC

[heliski22]

From Sasless

Finally.....when the Checklist clearly stated:
MGB Oil Pressure < 5psi.....Land Immediately!

From Squib66

Those who are critical of the pilots for not ditching into a choppy and freezing ocean need to remember that a certification loop-hole was cynically used to avoid fixing a known inability to operate with a loss of lubrication. Thirty minutes operation who have resulted in a safe landing.

Notwithstanding the validity of all the arguments back and forth and whilst acknowledging the possible influence of such a hostile environment upon flight crew trying to make the right response to a serious emergency in those circumstances, that checklist item has all the hallmarks of a corporate get-out-of-jail clause, does it not?

22

[zalt]

Heliski
Not if you consider the whole raft of other requirements to minimise such failures, apply crtical parts control processes, respond promptly to occurrences and so on.

[Outwest]

More on this tragic, preventable accident here:

Problems seen before fatal N.L. chopper crash: investigator - CTV News

Thanks Bill for trying, too bad it fell on deaf ears......

I can give SAC some leeway in how it handled the initial certification re the "extremely remote" clause...... no one is perfect, we all make mistakes. However, after the Broome incident clearly showed the error of this rational, I hold SAC/FAA 100% accountable for the Cougar accident.