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

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

Old 13th Mar 2009, 17:03
  #61 (permalink)  
 
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Tranny Lube failure

Correct me if I am wrong but I believe that your wondering is should a gearbox puke out all it,s lubrication ....do the blades keep turning?

Yes they do...until the gears and bearings within the box reach a temperature point that begins to bake the residual lubrication. Without any lubrication , the metal to metal contact and extreme forces that a 15 ton helicopter put upon them, begin to fail as well as build incredibly high frictional forces.
At this point, further application of power can overcome this rapidly increasing friction and keep the blades turning but at some point either the power runs out or the incredible heat build up causes a catastrophic failure and either a blades will begin to slow and eventually sieze or the mast / transmission will fail. At this point your a greasy manhole cover and gravity wins another one
As the gearbox fails, the increasing friction also precludes successful autorotion.
With some operators, an impending gearbox failure (high teps and or low pressure) calls for a Land As Soon As Possible and in other cases....a Land or Ditch IMMEDIATLY I
I am curious as to the S92,s RFM Emergency Checklist and/or Cougar,s ECL calls for with respect to Gear Box malfunctions.

Last edited by rumline; 13th Mar 2009 at 17:13. Reason: the usual grade IV spelling & grammer
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Old 13th Mar 2009, 17:10
  #62 (permalink)  
 
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rumline, yes, that is what I am getting at.

I appreciate it varies from type to type, but are there any quantifiable indications as to how long this might take?

I ask as I would appreciate the experience of other pilots how to treat this type of situation, when overflying an area of hostile terrain, either unsuitable to land, or remote from help (in my case more likely to be over urbanized, mountainous, forested or desert area, rather than the ocean).

Naturally a bias would lean towards Land Immediately, unless otherwise indicated in the relevant type POH, and of course, prevention of getting into this state in the first place, assuming I had influence over the contributing factors.
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Old 13th Mar 2009, 17:24
  #63 (permalink)  
 
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Only one S92 accident in the NTSB database to date ( National Transportation Safety Board )

and two (including this one) in the Griffin database (Griffin Helicopters | Accident Statistics ).

This is the only S92 accident in which MGB is identified as a possible issue in these databases, and the only fatal S92 accident in these databases. Is this the first S92 accident in which fatalities have occurred?.

Last edited by EN48; 13th Mar 2009 at 17:49.
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Old 13th Mar 2009, 17:26
  #64 (permalink)  
 
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The machines that I am intimate with have never stated outright what those figures are.....and I doubt many will ....unless it.s a MIL Spec proviso (ie Blackhawk)
The figure that gets bandied about by the techs that dig into these hard-to reach places is 30mins....
I have known Bell mediums to sieze within 15mins ...others to have sustained serious damage (scrapped GB) in as little 3 mins...
There are many factors as to whether a gearbox holds together or self-destructs. Things like rate of fluid loss, payload being carried, ambient air temp, transmission design, fluid being used .....all the way to the tolerances within individual boxs (no two are exactly alike)
I have personally had two trannys puke thier fluid out....once from 55psi to Zero in about 30secs (fortunatly was just in the hover....whew!! and another it dropped at a rate about 5psi /min (where I elected to carry on to first landfall....no damage...a/c returned to service)
It is my personal evil monkey lurking in the closet when it comes to helos....You might have 2 hydralics, 2 engines, 2 generators, 2 inverters, instrument redundancy......but there,s only one tranny....take care of it!
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Old 13th Mar 2009, 17:27
  #65 (permalink)  
 
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In the event of possible MGB failure, I think all aircraft types would have a Land/Ditch Immediately policy. Obviously, that doesn't apply if you have an emergency lubrication system, or that system has run for its prescribed amount of time. But once you have a gearbox about to fail, there is only one place you should be - On the ground / Water.

As to Autorotation. That isn't a requirement for a Gear Box problem, although I gather that was included in the early reports of this accident. I always understood that in the event of gearbox oil running out, the best policy was to land or ditch with power on, in order to overcome the increasing friction. I seem to remember a story of a Puma (332 or 330J) losing its lubrication and just making it to a deck that was close by - As they lowered the lever on landing, the blades made about 3 rotations and shuddered to a stop together with the smell of hot metal.
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Old 13th Mar 2009, 17:34
  #66 (permalink)  
 
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Special 25.....know a 212 that lost its lube...flew for about 13min before landing and upon throttle roll-off....blades siezed and spun the machine on the ground...
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Old 13th Mar 2009, 17:36
  #67 (permalink)  
 
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If you are involved in any way with the S92 then you will know what the issues are, I think at this stage we shouldn't speculate but think of all involved.

NST
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Old 13th Mar 2009, 17:42
  #68 (permalink)  
 
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Only seven fatal accidents in "newer" Sikorsky helicopters (S76A or later) in last 10 years in NTSB database. None of these show MGB failure as a probable cause, however, in some cases, no cause determined.
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Old 13th Mar 2009, 17:45
  #69 (permalink)  
 
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Hope fades for 16 missing in Newfoundland helicopter crash

Latest news....

Search to be carried on until dark today, no more signs of victims, hope fading.
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Old 13th Mar 2009, 17:54
  #70 (permalink)  
 
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Searching data bases for accidents may not reveal nearly enough information to mold an informed opinion.
Many incidents occur that are resolved at the company level...
Some between the operator and the manufacturer
Others between the Minister, the Company and the Manufacturer.

ie: A MGB return line cracks and leaks oil out....oil pressure drops and pilot returns to base before there is a catastrophic failure.

Oil line is replaced and machine returns to service.

Perhaps the material used to manufacture the line wasn,t resilient enough....or perhaps the stand-offs were not positioned properly....but the fix is made. The company examines other similiar types and also replaces those lines with a stronger one....

Now we have a known issue ...and all the pilots/engineers all know about it but thats where it ends.
Perhaps chatting to collegues reveals that they too, have had similiar incidents....but again...it is possible that a known fault/flaw can go for years before being fully addressed

Terrible news that no one found.
Condolences and peace upon those left behind.
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Old 13th Mar 2009, 17:58
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Scenario1:
Originally Posted by Special 25 View Post
I always understood that in the event of gearbox oil running out, the best policy was to land or ditch with power on, in order to overcome the increasing friction. I seem to remember a story of a Puma (332 or 330J) losing its lubrication and just making it to a deck that was close by - As they lowered the lever on landing, the blades made about 3 rotations and shuddered to a stop together with the smell of hot metal.
Scenario2:
Originally Posted by rumline
know a 212 that lost its lube...flew for about 13min before landing and upon throttle roll-off....blades siezed and spun the machine on the ground...
Would it make sense then, in the above scenarios to:
scenario1 - (Splash 25) override the governor and keep power on when lowering collective
secnario2 - (rumline) roll off power very gradually (I assume this could pose some other risks, depending on state of MGB and various temps /stresses)

i.e. in both scenarios keep one eye glued to RRPM?
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Old 13th Mar 2009, 18:07
  #72 (permalink)  
 
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In the case of the 212.....the ECL (at the time) called for Land As Soon As Possible)
The PIC elected to fly to the first floating site suitable for landing ....at this point your well outside anything the checklist could possibly cover and just relieved to know your down.
As the tranny thrashes in its death-throes .....how to roll off the throttles was probobly the last thing on thier mind!
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Old 13th Mar 2009, 18:18
  #73 (permalink)  
 
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This is very sad and condolonces to all involved.

If it was MGB problems, all you have to do is read the S-92 forum. There has been a few problems with the MGB and the 92. The concentration however has been on it's FAR crashworthiness certification vs other helo models non-FAR(fully compliant) crashworthiness certification.

Personally I want a guarenteed MGB above anything else. We have procedures for almost all failures, but a MGB failure is unthinkable- hydraulics gone on a big machine? Altenators gone? Rotor rpm?

Again, I hope for the best for those unfortunate to be involved, but this must cause some investigation and rectification.
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Old 13th Mar 2009, 18:35
  #74 (permalink)  
 
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Just heard on the radio that search will continue until it gets dark this evening (March 13) then will probably resume tomorrow as a recovery effort.
The TSB plans on using a remotely contolled vehicle to conduct the underwater search. More news here:
CTV.ca | Search for chopper crash survivors continues Friday
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Old 13th Mar 2009, 18:51
  #75 (permalink)  
 
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I know most people seem to be focusing on the MGB and there was talk of past issues.

Am I correct in thinking that one of the launch machines (Norske Helicopters) had a problem involving Loss of MGB pressure in the first few hours of flying ? Think it was traced to a plastic component in the pump that had failed a bit earlier than expected.

Then there was an incident in Brunei quite recently that necessitated a forced landing. I think that was Main Transmission related, but not sure if the final conclusion has been reached.

Is this a fundemental problem with the 92 Gear Box and Main transmission or are these isolated events. Seems like a lot of issues for such a new aircraft. Hope they don't ground it as the UK Search & Rescue system depend on them now that the AB139 isn't working either !
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Old 13th Mar 2009, 19:13
  #76 (permalink)  
 
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I still feel that if you have not got oil pressure you are going to land, if you have a little make sure it don’t get to hot, if you have other indications along with the lack of or low pressure, the only place you are going is down, low, slow and ready for the possible wet arrival.
Any run dry time advertised by any manufacture in my humble view is an advisory regarding your ability to transition from your altitude to a possible safe controlled landing on ground or water.
No gear system will run reliably without oil, it cools lubricates and is the life blood of the transmission system.
After looking at the flight data available on line and the noting the point that they turned back to the shore, how close were they to the destination rig?
My comments above are general ones only and in no way try to explain any aspects of this tragic event.


Outhouse.

Last edited by outhouse; 14th Mar 2009 at 07:17.
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Old 13th Mar 2009, 19:14
  #77 (permalink)  
 
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Hope they don't ground it as the UK Search & Rescue system depend on them now that the AB139 isn't working either !
A fairly contentious comment on two fronts...

The UK SAR system does not depend on the S92. It is merely one element of a multi agency / platform system. If required to, either the RAF/ RN may be asked to cover for the Coast Guard within the constraints of their own manning / serviceability issues, as they have before, (just like the coastguard have helped out the military before) or the contractor will, as they have done in the past for the 139, provide alternative assets.

secondly, if in due course, the S92 is grounded then it will be for specific safety reasons. In which case I would argue that the safety of the crew(s) is of greater importance than the effect it may or may not have on the UK SAR system.

I appreciate Special that the comment was probably just a throw away line but in the present climate everything on these threads is being scrutinised by the media.

SW
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Old 13th Mar 2009, 19:25
  #78 (permalink)  
 
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Fair point and comment withdrawn - Had forgotten about the press !

Yes, it was meant as just a throw-away line, especially as I'm not really sure of the status of the AB139 right now. I guess not the right time for frivilous comments either - Apologies ! S 25
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Old 13th Mar 2009, 19:38
  #79 (permalink)  
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Outhouse:
After looking at the flight data available on line and the noting the point that they turned back to the shore, how close were they to the destination rig?
I was thinking the same and tried to figure it out:

The last flight of the same aircraft on flightaware.com between CYYT and the platform had a duration of 1:15.
They departed at 11:47 Z and declared the emergency at 12:15 Z. That's 27 min, so not even half way before they turned around and flew for another 10 min (or 17nm).


The media reports indicate an airliner saw the aircraft only minutes (expendable statement) after the crash already upside down... did it capsized after a somewhat successful ditching? Maybe the survivor was/will be able to tell; on TV he seemed to be conscious when they loaded him into the ambulance.

Last edited by Phil77; 13th Mar 2009 at 19:39. Reason: include quotation
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Old 13th Mar 2009, 19:57
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Phil77
That’s the worrying bit, the short time frame from turn round till the event.
The voice recording will give some info however the recovery of the airframe and CVR+ FDR will be a critical event in the investigation. So how deep is the water in the area and what is the commitment to recover?
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