Yet another deadly crash in Nepal

Nah, the Ercoupe is different. Only one pedal, and it was, in fact, "just for brakes". Many were owner modified from this as-designed configuration to a more conventional set up with rudder pedals etc.
 
Capngrog said:
Nah, the Ercoupe is different. Only one pedal, and it was, in fact, "just for brakes". Many were owner modified from this as-designed configuration to a more conventional set up with rudder pedals etc.
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Heh heh, yep. But I wonder if that could have been their primary trainer for ATP? Two pedals = required redundancy!
 
Seeing the video from the passenger inside the plane as it happened, it seems to me that something (no idea what) was agitating some of the passengers and one of them seemed alarmed right before it all went left. My take anyway.
 
MFE said:
Seeing the video from the passenger inside the plane as it happened, it seems to me that something (no idea what) was agitating some of the passengers and one of them seemed alarmed right before it all went left. My take anyway.
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Looks like we will know soon. I think they said the investigation will be complete in 45 days?
 
The lack of ILS was probably not a factor in this accident. Let me rephrase that: The lack of an ILS should not have been a factor in this accident (remembering the Asiana 214 crash at San Francisco on July 06, 2013).

I don't know about a "wrong stick input"; however, there was obviously a loss of control of the Yeti aircraft, probably caused by an aerodynamic stall. Can it be argued that unintentional aerodynamic stalls are due to improper control input ("stick input")? Yes.
 
Capngrog said:
The lack of ILS was probably not a factor in this accident. Let me rephrase that: The lack of an ILS should not have been a factor in this accident (remembering the Asiana 214 crash at San Francisco on July 06, 2013).

I don't know about a "wrong stick input"; however, there was obviously a loss of control of the Yeti aircraft, probably caused by an aerodynamic stall. Can it be argued that unintentional aerodynamic stalls are due to improper control input ("stick input")? Yes.
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The lack of an ILS at an airport just opened and with a 23,000 ft mountain only a few miles away simply shows the laxity of rules in commercial aviation in Nepal.

Of course, on a clear day it was probably unrelated, although flying an approach makes you follow procedures quite a bit more than hand flying the plane and even switching runways minutes before landing.

Stall recovery at 200 ft would have required bringing the nose down, keeping the stick straight, opposite rudder, and a prayer - yet all would have made little difference. They were simply low and slow, a deadly combo.

Let's wait to hear the tapes as well as what the black boxes tell us. I suspect somebody forgot to keep track of the airspeed with the proper flap configuration. Pokhara_Regional_International_Airport.jpg
 
Preliminary report.

According to this, they feathered the props instead of lowering the flaps.

Somehow that seems like such a big mistake for seasoned pilots. I still have my doubts as to what happened...
 

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Well Occam told me, again. Not surprising. Colgan Atlas UPS Pinnacle et al. Then there's the non-fatals; then there's the near misses that are making the rounds these days. And we'll leave out the suicides of course.

I understand people lean averse to pointing the finger at the dead, under a sentiment of not being perceived as kicking gravestones/inviting bad karma et al. Which is fine, but a non-sequitur; that's a public relations reflex. Only reason anyone would have ideological difficulty 'accepting' that humans miscontrol airplanes outright with a wallet full of credentials, is halo effect bias. And biases have to be acknowledged before anything can be done about them.

Human error happens, bias towards credentialism be damned. And it happens a lot more to the left of the mu. All we can do is analyze these sequences, acknowledge our own fallibility regardless of experience, and incorporate these lessons in earnest as part of our new mental baseline when strapping into, and hurling ourselves across the sky way too fast and for what our pink bags were rated for at the factory.

But we can learn from the mistakes of others without paying the price ourselves, imo. Safe flying and cavu skies.
 
It appears that making the mistake of manipulating the two propeller control levers instead of the single flap positioning lever would be incredibly unlikely. First there's the fact there is a lever for each propeller, and both would have to be grasped with the hand and moved. Even if the pilot didn't look at the levers before moving them, the tactile difference would be obvious.

Additionally, one would think the larger movement range and longer stroke of the propeller controls compared to the flap lever would trigger a muscle memory mechanism and alert the pilot a mistake had been made. That obviously didn't occur, and the pilots allowed the angle of attack to increase as the airspeed decayed, apparently oblivious to the situation.

The power quadrant and adjacent flap positioning lever:

Power_and_Condition_levers_of_ATR72-1536x1024.jpg
 
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3393RP said:
It appears that making the mistake of manipulating the two propeller control levers instead of the single flap positioning lever would be incredibly unlikely. First there's the fact there is a lever for each propeller, and both would have to be grasped with the hand and moved. Even if the pilot didn't look at the levers before moving them, the tactile difference would be obvious.

Additionally, one would think the larger movement range and longer stroke of the propeller controls compared to the flap lever would trigger a muscle memory mechanism and alert the pilot a mistake had been made. The obviously didn't occur, and the pilots allowed the angle of attack to increase as the airspeed decayed, apparently oblivious to the situation.

The power quadrant and adjacent flap positioning lever:

Power_and_Condition_levers_of_ATR72-1536x1024.jpg
Click to expand...
As my dad used to say, when your hand grabs the wrong control, it still knows what to do with it.
 
3393RP said:
It appears that making the mistake of manipulating the two propeller control levers instead of the single flap positioning lever would be incredibly unlikely.
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Juan Browne's (Blancolirio) analysis (posted above) does a good job of showing how this is both plausible and likely.

HHH
Screen Shot 2022-12-28 at 9.38.21 AM.png
 
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I haven't seen Juan's analysis, but while I agree that mistaking the prop levers for the flaps would be unlikely, it would certainly be possible. Remember that these were two captains flying and were used to manipulating these controls with their right hands instead of the left, as was probably the case in this incident. Aircraft crashes usually occur because of an incredibly unlikely chain of events.
 
Capngrog said:
I haven't seen Juan's analysis, but while I agree that mistaking the prop levers for the flaps would be unlikely, it would certainly be possible. Remember that these were two captains flying and were used to manipulating these controls with their right hands instead of the left, as was probably the case in this incident.
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That's a large part of Juan's analysis as well.

HHH
Screen Shot 2022-12-28 at 9.38.21 AM.png
 
Hunter Handsfield said:
Juan Browne's (Blancolirio) analysis (posted above) does a good job of showing how this is both plausible and likely.

HHH
View attachment 115077
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I wouldn't think it took much of an analysis. It's obvious that's what happened. I can't watch his videos, they're too pedantic and tedious.

As in many crashes, it's difficult to square up how these errors are made, but there it is.
 
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Capngrog said:
I haven't seen Juan's analysis, but while I agree that mistaking the prop levers for the flaps would be unlikely, it would certainly be possible. Remember that these were two captains flying and were used to manipulating these controls with their right hands instead of the left, as was probably the case in this incident. Aircraft crashes usually occur because of an incredibly unlikely chain of events.
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the thing that makes me think no way, is that in the auto position, the gates on the condition levers have to be pulled up to move them out of the auto position to move them to feather. i can't believe that happened. however, it has been done. we had a new hire FO do it on the ground during aircraft training years ago, the check airman blew all four tires trying to get it stopped.
 
The bottom line, there was likely nothing mechanically wrong with this plane when it crashed. Yeah, maybe over-simplifying.
 
So there I was… A4 advanced strike instructor…

We had a foreign exchange instructor. Great guy! Brazilian T2 guy. However, one day towards the end of his instructor under training bombing flights when…

Instead of “pickle pause pull” (at 350 kts, 30 degrees nose low, pull 3.5g’s)

He “lowered gear, pause pulled”. Hmmm, prolly best to just leave it down at this point. El Sweato, base is like 10 miles away.

Of course it was an A4, gear simply went down! Excessive speed bent up a coupla doors, but all was good.

Point is, those sorts of mistakes are easier to make than ya might think.
 
3393RP said:
It appears that making the mistake of manipulating the two propeller control levers instead of the single flap positioning lever would be incredibly unlikely. First there's the fact there is a lever for each propeller, and both would have to be grasped with the hand and moved. Even if the pilot didn't look at the levers before moving them, the tactile difference would be obvious.

Additionally, one would think the larger movement range and longer stroke of the propeller controls compared to the flap lever would trigger a muscle memory mechanism and alert the pilot a mistake had been made. That obviously didn't occur, and the pilots allowed the angle of attack to increase as the airspeed decayed, apparently oblivious to the situation.

The power quadrant and adjacent flap positioning lever:

Power_and_Condition_levers_of_ATR72-1536x1024.jpg
Click to expand...
You also have to lift the handles to get them into FTR. You don't just pull them back like the flaps.
 
hindsight2020 said:
Well Occam told me, again. Not surprising. Colgan Atlas UPS Pinnacle et al. Then there's the non-fatals; then there's the near misses that are making the rounds these days. And we'll leave out the suicides of course.

I understand people lean averse to pointing the finger at the dead, under a sentiment of not being perceived as kicking gravestones/inviting bad karma et al. Which is fine, but a non-sequitur; that's a public relations reflex. Only reason anyone would have ideological difficulty 'accepting' that humans miscontrol airplanes outright with a wallet full of credentials, is halo effect bias. And biases have to be acknowledged before anything can be done about them.

Human error happens, bias towards credentialism be damned. And it happens a lot more to the left of the mu. All we can do is analyze these sequences, acknowledge our own fallibility regardless of experience, and incorporate these lessons in earnest as part of our new mental baseline when strapping into, and hurling ourselves across the sky way too fast and for what our pink bags were rated for at the factory.

But we can learn from the mistakes of others without paying the price ourselves, imo. Safe flying and cavu skies.
Click to expand...
This right here is the paradigm I live by as a professional pilot. I am the threat. Every leg I remind my partner in crime that I am imperfect, have never flown an error free flight and expect correction when I deviate from the SOP. That’s the only way this aviation thing works in my opinion. Well that and a basic level of giving a ****.
 
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