Bearskin Metro 3 CYRL accident - Speculation thread

[cncpc]

What facts there are are not inconsistent with a plenum failure.

[1&2SpooledUp]

What facts there are are not inconsistent with a plenum failure.

What Facts ? Please elaborate.....

[cncpc]

What facts there are are not inconsistent with a plenum failure.

What Facts ? Please elaborate.....

Sure, on the understanding that I'm not saying plenum failure is the only possible event in the chain, or necessarily even was an event.

• The TSB says that the crew declared some sort of emergency about 10 minutes back.
  
  The survivor says that there was some sort of engine problem.
  
  The crew were not able to maintain altitude, assuming that the final moments of the flight were with a failed/shutdown engine.

Those are three facts.

It is an observation that this certainly isn't clear cut pilot error.

Plenum failures...

There is a lot out there on plenum failures and the whole dash series of the 331. This is the most illustrative.

http://www.tc.gc.ca/eng/civilaviation/c ... 07-420.htm

A failure is very likely preceded by a fire warning as a nearby wire is heated up. This translates to "some sort of emergency", short of an actual engine failure. It can result in high temps, and a subsequent change of torque and other crew behaviors.

If the plenum violently "explodes", it can distort and even break loose cowlings, the negative torque sensing mechanism will move the blades towards feather but not to full feather, and the T lever may not work to feather.

In those circumstances, level flight may not be possible and the aircraft descends in spite of all the crew can do.

I didn't come up with this. A former TSB investigator did.

[stef]

There are many failures that this accident is "not inconsistent with." I'm guessing we'll have to exercise a little patience to find out what happened with this one.

My sincere condolences to the families, friends and coworkers of the victims of this terrible accident.

[cncpc]

There are many failures that this accident is "not inconsistent with." I'm guessing we'll have to exercise a little patience to find out what happened with this one.

My sincere condolences to the families, friends and coworkers of the victims of this terrible accident.

Well, with respect, no, there are not "many failures" that could produce the same fact pattern.

This is a transport category aircraft certified as capable of flight on one engine. The problem was an engine problem, according to the survivor. There was no shortage of fuel. The only other plausible scenario is an engine left running as per the Northern Thunderbird scenario, then a decision to shut down, and pulling the wrong T lever.

This is a photo from Global. There is an area of scorching black on the top and down the side, and behind that there is an area in which the white paint has been melted to bubbling, and the red stripes are gone. That appears to be the area covering most of the plenum.

[1&2SpooledUp]

There are many failures that this accident is "not inconsistent with." I'm guessing we'll have to exercise a little patience to find out what happened with this one.

My sincere condolences to the families, friends and coworkers of the victims of this terrible accident.

Well, with respect, no, there are not "many failures" that could produce the same fact pattern.

This is a transport category aircraft certified as capable of flight on one engine. The problem was an engine problem, according to the survivor. There was no shortage of fuel. The only other plausible scenario is an engine left running as per the Northern Thunderbird scenario, then a decision to shut down, and pulling the wrong T lever.

This is a photo from Global. There is an area of scorching black on the top and down the side, and behind that there is an area in which the white paint has been melted to bubbling, and the red stripes are gone. That appears to be the area covering most of the plenum.

As you can see by the scorched trees all around, their was
a post crash fire that probably caused the paint scorching. Although your theory is plausable, it's not the only scenario that could have caused this accident. We need more solid facts other than the media reporting what one of the survivors may have said about an engine problem.

[frozen solid]

It may or may not make a huge difference but let's recall that the survivor is also a pilot- his observations may be a little more astute than a layperson's.

[learcapt]

Cncpc....unless I missed something, what are your credentials? Are you an accident investigator of some sort? Are you involved with this investigation?

If none of the above is true, STFU. Nobody cares about your guesses. Let the investigators do their job, friends and family mourn and wait to see what happens. I flew Merlin's, Metros and others with 331 power and I am not jumping to conclusions here.

Sorry for the rant everyone, just pissed me off.

[cdnpilot77]

..

[PositiveRate27]

I may also point out, the 331's on the Metros don't have "T-Handles", they have "Stop and Feather Controls". They are located on the pedestal underneath the speed levers, to the right of the trim select. They are circular in shape and red in color. They mechanically cut the fuel and feather the propeller.

I would encourage you to be accurate with your terminology and to refrain from speculation until more info comes to light.

[cncpc]

Cncpc....unless I missed something, what are your credentials? Are you an accident investigator of some sort? Are you involved with this investigation?

If none of the above is true, STFU. Nobody cares about your guesses. Let the investigators do their job, friends and family mourn and wait to see what happens. I flew Merlin's, Metros and others with 331 power and I am not jumping to conclusions here.

Sorry for the rant everyone, just pissed me off.

Not that it matters, but yes, I have done some accident investigations. I am in charge of safety and operations in a carrier that operates a good number of 331s and I don't know that I'd say this accident didn't have something to do with a loss of power is "jumping to conclusions". I'm quite certain it had something to do with a loss of power and I expect all those "nobodies" you consider to be like minded to you, are pretty sure about that as well. That's hardly a guess.

I have an interest in knowing as soon as possible if the circumstances of this accident and any involvement the engine may have had raise a concern with those of our aircraft which are 331 powered. I seriously doubt I'm the only flight ops guy in Canada running Garretts that is concerned about what happened here. That's not jumping to conclusions. It is simply saying "What might have happened and could it happen to us"/

I called a long time friend who was both a Transport Canada and TSB investigator and told him it was a Metro which declared an emergency and within ten minutes had flown into the ground in VFR weather. He said the immediate thing that would come to mind from his experience would be a plenum failure. We talked about the likely sequence of fire warning, rupture, and potential loss of the ability to feather. He referred me to the Terrace accident, on which he was an investigator. I have just repeated what he said to me. I don't consider what he told me to be a definitive answer, but it certainly wasn't a guess. I took it as a starting point to understanding what might have caused this accident, which is what is discussed in a forum called Accidents, Incidents & Overdue Aircraft.

We have examined our own procedures, especially what we do when we get mystery fire warnings, and we have done what prudent people should do. That's not to say this was a plenum failure, or that we weren't already aware of the issue and the Terrace accident, but we did make a small change. If we get unexplained fire warnings, we will in future always check closely for plenum cracks.

I'm sorry if that's pissed you off.

[cncpc]

As you can see by the scorched trees all around, their was a post crash fire that probably caused the paint scorching. Although your theory is plausable, it's not the only scenario that could have caused this accident. We need more solid facts other than the media reporting what one of the survivors may have said about an engine problem.

I saw that there was a fire. But I don't see any evidence of a fire right where the engine is sitting. The green twigs don't appear to be burned, and there isn't any fuel that would have done that type of burning. In my opinion anyway. I think the heat came from inside.

I never said it was the only scenario. I merely said that the plenum failure theory was not inconsistent with what is known.

I hardly think any of this is disrespectful to the victims, and certainly not the crew. I see it as unlikely that this was a pilot error crash. Whatever it was, the crew seems to have had the deck stacked against them.

[cncpc]

I may also point out, the 331's on the Metros don't have "T-Handles", they have "Stop and Feather Controls". They are located on the pedestal underneath the speed levers, to the right of the trim select. They are circular in shape and red in color. They mechanically cut the fuel and feather the propeller.

I would encourage you to be accurate with your terminology and to refrain from speculation until more info comes to light.

Thanks for your encouragement. Stop and Feather controls, we call em the same thing. I'm quite familiar with how they work. Some Garretts have twist and turn handles, some have red knobs. I don't think that is the issue. One possible issue, the minutae of the operating mechanism aside, is whether there might have been a problem feathering.

[Taiser]

Cncpc....unless I missed something, what are your credentials? Are you an accident investigator of some sort? Are you involved with this investigation?

If none of the above is true, STFU. Nobody cares about your guesses. Let the investigators do their job, friends and family mourn and wait to see what happens. I flew Merlin's, Metros and others with 331 power and I am not jumping to conclusions here.

Sorry for the rant everyone, just pissed me off.

WOW...

What's the point of the thread if not to speculate what happened. If it bugs you that much, ignore the thread! I got no issues with it, as long as it's done with some respect. I fly on the Bear all the time and believe me I'm interested in what happened, including theories. That's how most investigations work, follow the clues, come up with a theory of what could have happened, figure out if it makes sense and find the evidence to prove it.

Some of my counterparts at work are at this scene working with TSB. Black box has been found. Hopefully it sheds some light soon on what happened.

[olddirtyloud]

As you can see by the scorched trees all around, their was a post crash fire that probably caused the paint scorching. Although your theory is plausable, it's not the only scenario that could have caused this accident. We need more solid facts other than the media reporting what one of the survivors may have said about an engine problem.

I saw that there was a fire. But I don't see any evidence of a fire right where the engine is sitting. The green twigs don't appear to be burned, and there isn't any fuel that would have done that type of burning. In my opinion anyway. I think the heat came from inside.

I'm not sure which photo you are looking at, but the green twigs are in the foreground. If you look at the tree to the right, you can see the burn starts midway up the branch. The unburned part is the same area as the green twigs. If you look at the engine, there is a tree knocked over on it, completely scorched, thus giving evidence that there was in fact a fire where the engine lies.
The photo posted here doesn't show the whole picture, enlarge the one from:
http://www.winnipegfreepress.com/local/ ... 34371.html and you'll see it.

[CID]

Metro is NOT transport category. Commuter category. And some are normal category with SFAR41 which makes them pretty much commuter category.

[cncpc]

As you can see by the scorched trees all around, their was a post crash fire that probably caused the paint scorching. Although your theory is plausable, it's not the only scenario that could have caused this accident. We need more solid facts other than the media reporting what one of the survivors may have said about an engine problem.

I saw that there was a fire. But I don't see any evidence of a fire right where the engine is sitting. The green twigs don't appear to be burned, and there isn't any fuel that would have done that type of burning. In my opinion anyway. I think the heat came from inside.

I'm not sure which photo you are looking at, but the green twigs are in the foreground. If you look at the tree to the right, you can see the burn starts midway up the branch. The unburned part is the same area as the green twigs. If you look at the engine, there is a tree knocked over on it, completely scorched, thus giving evidence that there was in fact a fire where the engine lies.
The photo posted here doesn't show the whole picture, enlarge the one from:
http://www.winnipegfreepress.com/local/ ... 34371.html and you'll see it.

Thanks. I did have a look at the Free Press photo. You make some sound observations from that more expanded picture.

[teacher]

As long as it's done in a respectful manner there is NOTHING wrong with speculating on an accident. It generates important discussions on air safety.

[2.5milefinal]

EDIT
Moderators: When you separate threads its confusing at best.
You guys should maybe setup a Condolences Forum.
Iliopolus_1
...not worth my time.

I keep trying to stay away from this place. But like a drug or porn addict I keep coming back.
Fly safe all. Im out (again)

[YWGGuy]

Metro is NOT transport category. Commuter category. And some are normal category with SFAR41 which makes them pretty much commuter category.

You're confusing this. You're right in the fact a Metro flies under 704 (commuter) regulations. The aircraft however (being above 12,500lbs) is certified as a transport category aircraft.