Bearskin Metro 3 CYRL accident - Speculation thread

[J31]

A TPE331 engine failure with NTS (Negative Torque Sensing) is very easy to deal with. However if it is still running and at 0% torque you are now dealing with a lot of drag, so much that you will lose control in short order unless the "Stop and Feather" is pulled.

The NTS will increase blade angle if it senses negative torque (-4% torque) in the case where the engine fails and spools down. In this case the engine was still running and driving the prop to fine pitch trying to increase N1 RPM to the commanded level so no NTS. You must follow the drill and "Stop and Feather" the engine. Flying the airplane will not be enough with massive drag on one side.

No disrespect to these guys as I am sure they were competent Metro pilots. They may not have understood the necessity of shutting down a running engine that was not producing torque. As noted above it would been very hard to to analyze what was going on that night.

It has been a lot of years since I did any training in the Metro but I seem to remember that we never got close to 0% torque during simulated engine failures. If the trainee was slow getting the "Stop and Feather" drill done the airplane would soon be departing controlled flight thus the instructor never let it get too far.

These guys had their hands full and most likely would have landed fine had they pulled the "Stop and Feather" knob.

I too think the TSB did a very thorough investigation into this crash.

Hopefully the message to others is to know your machine as not all procedures work for all aircraft.

[BTD]

I read the CBC report of the TSB report. It leaves me with more questions than answers.

Maybe you should read the actual report, not a media report, of a report.

I'm assuming your not familiar with the TPE331 and its systems...

500' AGL, something goes wrong, how do you feather something instantly that has more signs saying its fine than not....

And Doc, when you have 4 out of 5 gauges telling you the engine is AOK, how do you conclude in seconds (since it was less than a minute from failure to trees, and less than that from things going south), that you need to shut that engine down?
It's always easy to be an expert when your sitting in a comfy chair with all the information, not so easy when its at night and your fighting for your life...

+1

[fche]

It would have been helpful to see a transcript of the CVR and the data curves from the FDR, to figure out whether they were aware of the airspeed loss, and to explain the power reductions tens of seconds before the crash.

[Ki-ll]

The report doesn't show the airspeed graph, which is too bad. That table that they gave is not enough. I wonder what the speed was at the first power reduction and what was the actual reason for the power reduction. The airplane rolled because the airspeed was low. Was the reduction in power a contributing factor to the airspeed loss or was the propeller drag the factor that caused it? I remember from flight training that once you reduce the power on the good engine with the dead engine windmilling the airspeed drops very quickly.
This was probably the worst engine failure situation one could have. Propeller was at the lowest pitch and the spinning energy was delivered by the engine, the propeller was not windmilling, it was being spun at 96% at low pitch.

[MrWings]

What happened to the Mayday 10 minutes out that TSB initially reported?

[Illya Kuryakin]

I read the CBC report of the TSB report. It leaves me with more questions than answers.

Maybe you should read the actual report, not a media report, of a report.

I'm assuming your not familiar with the TPE331 and its systems...

500' AGL, something goes wrong, how do you feather something instantly that has more signs saying its fine than not....

And Doc, when you have 4 out of 5 gauges telling you the engine is AOK, how do you conclude in seconds (since it was less than a minute from failure to trees, and less than that from things going south), that you need to shut that engine down?
It's always easy to be an expert when your sitting in a comfy chair with all the information, not so easy when its at night and your fighting for your life...

Um, yaw? Dead foot, dead engine a new concept for some of you I guess? A sudden yaw sends me to a shut down if there are no other indications. But, what would I know? You should ask Doc. He'd know.
Illya

PS. I flew Metros for two years. Flight Safety trained. You?

[boeingboy]

The Bearskin Airlines SOPs for a non-precision engine-out approach requires the crew to change (re-configure) the aircraft flap and gear positions 3 times during the final stages of the approach (Appendix B). Frequent configuration changes over a short distance or period of time can lead to confusion as to the configuration state of the aircraft.Footnote 16

This is the part that has me concerned. Why all the crap? re-configuring so many times? Even TSB said in the report the crew may have been confused in the steps required as the raised and then lowered the gear.....like they were trying to do everything at once.

[Ki-ll]

The Bearskin Airlines SOPs for a non-precision engine-out approach requires the crew to change (re-configure) the aircraft flap and gear positions 3 times during the final stages of the approach (Appendix B). Frequent configuration changes over a short distance or period of time can lead to confusion as to the configuration state of the aircraft.Footnote 16

This is the part that has me concerned. Why all the crap? re-configuring so many times? Even TSB said in the report the crew may have been confused in the steps required as the raised and then lowered the gear.....like they were trying to do everything at once.

The point of all the re-configuration is to reduce the drag. Gear is a source of very significant drag on the Metro, so the point is to clean the aircraft up. I was taught to retract the gear in case of levelling off at the MDA for sigle engine circling in the Metro. I do not know if I would have retracted the gear in this case. Anytime there is an issue with the engine, the spinning propeller should be the first concern, it has the potential to create many times more drag than any gear.

[fche]

Um, yaw? Dead foot, dead engine a new concept for some of you I guess?

Good point ... the TSB report doesn't even mention pilot error in the findings as such; doesn't that seem unusual? _Should_ they have been able to identify the nature ... etc.?

3.1.3. The crew were unable to identify the nature of the engine malfunction, which prevented them from taking timely and appropriate action to control the aircraft.

[Illya Kuryakin]

The Bearskin Airlines SOPs for a non-precision engine-out approach requires the crew to change (re-configure) the aircraft flap and gear positions 3 times during the final stages of the approach (Appendix B). Frequent configuration changes over a short distance or period of time can lead to confusion as to the configuration state of the aircraft.Footnote 16

This is the part that has me concerned. Why all the crap? re-configuring so many times? Even TSB said in the report the crew may have been confused in the steps required as the raised and then lowered the gear.....like they were trying to do everything at once.

WHAT?? It's max power, drag check, identify, verify, feather!! Reconfigure the flap and gear three times????? On an approach????? WHY?? On approach, if it suddenly yaws, apply dashboard power. If it yaws even more, feather the engine. You're on approach. If the gear is down, and the aircraft is flyable, leave the gear down. If it's not, retract and continue until it's safe to extend it. Blind adherence to this SOP will kill you. It well may have.
Illya

[Illya Kuryakin]

The point of all the re-configuration is to reduce the drag. Gear is a source of very significant drag on the Metro, so the point is to clean the aircraft up. I was taught to retract the gear in case of levelling off at the MDA for sigle engine circling in the Metro. I do not know if I would have retracted the gear in this case. Anytime there is an issue with the engine, the spinning propeller should be the first concern, it has the potential to create many times more drag than any gear.

To reduce drag, select the gear and flaps up ONE TIME ONLY! The gear is a "very significant source of drag" on almost EVERY airplane. On the F27, for example, the main gear are used as speed brakes!
Retract the gear at the MDA for single engine circling, and you're VERY likely to forget to put it back down! You'll have your paws full just flying a circling approach at minimums on one engine! WHO taught you that wee gem. Really? It angers me that you were taught this! Personally, I don't do single engine circling approaches. If I can't land straight in on one, I go somewhere that I can. Of course, this assumes WX at minimums. I'll happily circle at 1000 feet.
I've been here. Several times. Once you've "given 'er all she's got" the next thing on the agenda is to clean it up.......including feathering the offending propeller. The airplane ALWAYS "points" to the dead engine.
Illya

[Ki-ll]

Well, it was a standard procedure for the non-precision approaches at Bearskin as shown on the diagram from the SOPs, I do not know if that's the case now. The diagram assumes that you are in IMC, so 100' above minimums you would retract the gear and bring the flaps to 1/4.
I agree with you, there is no value in retracting the gear if the airplane is flying and you are 1 mile away from the runway in VMC conditions. Moreover, it really is puzzling that feathering was not accomplished. TSB was so puzzled at that they actually could not come up with a definitive answer.

[ogc]

The point of all the re-configuration is to reduce the drag. Gear is a source of very significant drag on the Metro, so the point is to clean the aircraft up. I was taught to retract the gear in case of levelling off at the MDA for sigle engine circling in the Metro. I do not know if I would have retracted the gear in this case. Anytime there is an issue with the engine, the spinning propeller should be the first concern, it has the potential to create many times more drag than any gear.

To reduce drag, select the gear and flaps up ONE TIME ONLY! The gear is a "very significant source of drag" on almost EVERY airplane. On the F27, for example, the main gear are used as speed brakes!
Retract the gear at the MDA for single engine circling, and you're VERY likely to forget to put it back down! You'll have your paws full just flying a circling approach at minimums on one engine! WHO taught you that wee gem. Really? It angers me that you were taught this! Personally, I don't do single engine circling approaches. If I can't land straight in on one, I go somewhere that I can. Of course, this assumes WX at minimums. I'll happily circle at 1000 feet.
I've been here. Several times. Once you've "given 'er all she's got" the next thing on the agenda is to clean it up.......including feathering the offending propeller. The airplane ALWAYS "points" to the dead engine.
Illya

The metro II at or near gross weight likely wont maintain level flight with gear down and an engine out.

Never had to experience it myself, but its what i was trained. Thus if you are in the circle and not yet decending for the field the gear comes up. 3's and 23's are may be different.

I dont think anyone plans to do a single engine circling. But shit happens and on a very bad day you might have to so i dont see the harm in having run through the procedure before.

[Illya Kuryakin]

The point of all the re-configuration is to reduce the drag. Gear is a source of very significant drag on the Metro, so the point is to clean the aircraft up. I was taught to retract the gear in case of levelling off at the MDA for sigle engine circling in the Metro. I do not know if I would have retracted the gear in this case. Anytime there is an issue with the engine, the spinning propeller should be the first concern, it has the potential to create many times more drag than any gear.

To reduce drag, select the gear and flaps up ONE TIME ONLY! The gear is a "very significant source of drag" on almost EVERY airplane. On the F27, for example, the main gear are used as speed brakes!
Retract the gear at the MDA for single engine circling, and you're VERY likely to forget to put it back down! You'll have your paws full just flying a circling approach at minimums on one engine! WHO taught you that wee gem. Really? It angers me that you were taught this! Personally, I don't do single engine circling approaches. If I can't land straight in on one, I go somewhere that I can. Of course, this assumes WX at minimums. I'll happily circle at 1000 feet.
I've been here. Several times. Once you've "given 'er all she's got" the next thing on the agenda is to clean it up.......including feathering the offending propeller. The airplane ALWAYS "points" to the dead engine.
Illya

The metro II at or near gross weight likely wont maintain level flight with gear down and an engine out.

Never had to experience it myself, but its what i was trained. Thus if you are in the circle and not yet decending for the field the gear comes up. 3's and 23's are may be different.

I dont think anyone plans to do a single engine circling. But shit happens and on a very bad day you might have to so i dont see the harm in having run through the procedure before.

I've flown Metro IIs. They will maintain with the gear down and one feathered. Been there, done that. Spade doors (most companies have removed them) can be a little more difficult. But, we didn't have them. I'd take the tail wind and land a bit longer rather than do a single engine circling. Every time. Or call it a missed. Your training otherwise is scary. In that scenario, I guarantee you'll forget the gear 1 in 5 attempts.
Illya

[boeingboy]

The point of all the re-configuration is to reduce the drag. Gear is a source of very significant drag on the Metro, so the point is to clean the aircraft up. I was taught to retract the gear in case of levelling off at the MDA for sigle engine circling in the Metro. I do not know if I would have retracted the gear in this case. Anytime there is an issue with the engine, the spinning propeller should be the first concern, it has the potential to create many times more drag than any gear.

I understand all that - I've done single engine work as well.

They were not talking about circling approaches......" Bearskin Airlines SOPs for a non-precision engine-out approach " Why in gods name would they be re-configuring 3 times??? Maybe if you were 8 miles back - fine, suck up the gear and flaps until landing is assured and the airplane is under control. Short final below 1000' (they were at 500') is not the place to be scr$ing around. Fly the airplane.

It almost sounds as if they forgot to do this....trying to do everything else.

[Ki-ll]

The point of all the re-configuration is to reduce the drag. Gear is a source of very significant drag on the Metro, so the point is to clean the aircraft up. I was taught to retract the gear in case of levelling off at the MDA for sigle engine circling in the Metro. I do not know if I would have retracted the gear in this case. Anytime there is an issue with the engine, the spinning propeller should be the first concern, it has the potential to create many times more drag than any gear.

I understand all that - I've done single engine work as well.

They were not talking about circling approaches......" Bearskin Airlines SOPs for a non-precision engine-out approach " Why in gods name would they be re-configuring 3 times??? Maybe if you were 8 miles back - fine, suck up the gear and flaps until landing is assured and the airplane is under control. Short final below 1000' (they were at 500') is not the place to be scr$ing around. Fly the airplane.

It almost sounds as if they forgot to do this....trying to do everything else.

Nowhere is says to re-configure three times. You configure the airplane once, with flaps at 1/2 and gear down. 100 feet above MDA you retract the gear and flaps to 1/4. Whe landing is assured you put the gear down and flaps to 1/2 then full. The purpose of this configuration change is to reduce the drag as pilots were told that the airplane would not fly with the gear down. I am not advocating for this, I am stating the facts.
We will likely never know why they cycled the gear. The fact that they did and the fact that they deemed a radio call a higher priority over identifying the problem (TSB said there was no discussion of this on the CVR) indicates a high workload situation.
Like I said before, it would be good to see the CVR transcript overlayed over aircraft flight parameters and crew actions. That might shed some light on the questions everyone has.

[boeingboy]

Well - maybe I misread this quote then...

".... requires the crew to change (re-configure) the aircraft flap and gear positions 3 times during the final stages of the approach "

Your explanation is more along the lines of what I said earlier, but to me "final stages of the approach" is different than what your talking about.

[Ki-ll]

Well - maybe I misread this quote then...

".... requires the crew to change (re-configure) the aircraft flap and gear positions 3 times during the final stages of the approach "

Your explanation is more along the lines of what I said earlier, but to me "final stages of the approach" is different than what your talking about.

I was the one who misread it, my apologies, it has been a long day today.
SOP's do require these changes of configuration, it is just hard for me to see how the SOP's would be confusing someone who is 5 miles final, visual and in control of the airplane. I think they retracted the gear to clean the airplane up, instinctively, out of stress, but then realized that it was not necessary.
What interests me are those two power reductions and the point where the flaps were selected to full. The collision with the trees was in full landing configuration, but the engine fault happened while they were partially configured.

[Maynard]

You guys are all acting like it was a 'kaboom, hard yaw left, all the bells and whistles telling them they had an engine failure'. It wasn't. Did anyone actually read the report, or jump to the end. With a low power setting, and gusty winds, at 500' the airplane is getting bumped around, and anyone who flies a metro knows how much it yaws back and forth. So with a low power setting, how obvious is it now that you had an engine fail? As for the gear ret/ext, after a failure, first thoughts are clean it up, so maybe they raised the gear, added the power, looked out the window, runway now probably only 1 mile away, ok put the gear back down, reduce the power to land, at which point the drag would have worsened to the point that it did. Now the airplane is banking hard left, and losing speed. We can sit here all day and wonder why they didn't pull the stop and feather. We will never know for sure, but given the 1 in a million scenario that it happened in, I have a good hypothesis that 9/10 people would have ended up in the same spot.

[JayVee]

You guys are all acting like it was a 'kaboom, hard yaw left, all the bells and whistles telling them they had an engine failure'. It wasn't. Did anyone actually read the report, or jump to the end. With a low power setting, and gusty winds, at 500' the airplane is getting bumped around, and anyone who flies a metro knows how much it yaws back and forth. So with a low power setting, how obvious is it now that you had an engine fail? As for the gear ret/ext, after a failure, first thoughts are clean it up, so maybe they raised the gear, added the power, looked out the window, runway now probably only 1 mile away, ok put the gear back down, reduce the power to land, at which point the drag would have worsened to the point that it did. Now the airplane is banking hard left, and losing speed. We can sit here all day and wonder why they didn't pull the stop and feather. We will never know for sure, but given the 1 in a million scenario that it happened in, I have a good hypothesis that 9/10 people would have ended up in the same spot.

+1