Agree. What a Gordian Knot of a topic.
Yeti Airlines crash ATR 72
- Thread starter Cherokee_Cruiser
- Start date
Agree. What a Gordian Knot of a topic.
ZapBrannigan
If it ain’t a Boeing, I’m not going. No choice.
Trump is smart in the same way that I have six pack and and a full head of hair. 
zmiller4
Well-Known Member
Yup.
I don’t know if it’s still the case, but a difference between the 42 and 72 was that with any ice protection on the aoa limits for shaker/pusher activation were lowered in the 72 (because ice) but not the 42.
Apophis
Resident Iconoclast
Stick pusher activation on the -42 occurs at 15 degrees AOA. You are correct, it doesn’t change with ice protection (specifically either or both “horns” selected on since it’s these specific push buttons that control icing/normal AOA). The AOA required to get the shaker does change though (goes from 12.5 to 7.5 or 8.5 temporarily for takeoff).
-72 both shaker and pusher AOA are based on flap position and whether or not horns anti icing is on or off. You also have to specifically press the “icing AOA” push button in both variants to return the system to normal non-icing values after de-selecting horns anti-icing.
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"On Feb 6th 2023 Nepal's AIC reported that both flight data and cockpit voice recorders were successfully read out in Singapore. According to first analysis of the flight data recorders both propellers of the aircraft went into the feather position. The reason for the feathering of both propellers is still being determined, human factors as well as technical factors are still under investigation."
SurferLucas
Southern Gentleman
DAYUM…
"On Feb 6th 2023 Nepal's AIC reported that both flight data and cockpit voice recorders were successfully read out in Singapore. According to first analysis of the flight data recorders both propellers of the aircraft went into the feather position. The reason for the feathering of both propellers is still being determined, human factors as well as technical factors are still under investigation."
Mais… Pourquoi?
SurferLucas
Southern Gentleman
Another ATR down, from feathering the prop (this case both of them, and not just the wrong one, like in Taiwan).
Maximilian_Jenius
Super User
I'm only an 11 hour multi rated pilot. But at least in a Seneca, I think its hard to accidently feather a prop. You have to intentionally do it, or not being paying attention. I know/hear that turbo props have auto feather. Is it easy to accidently feather a prop on a turboprop?
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SlumTodd_Millionaire
Most Hated Member
Could it be possible that someone accidentally feathered instead of going full forward for landing? I can’t imagine two separate autofeather systems failing to the feather position at the same time.
SurferLucas
Southern Gentleman
The Q, the autofeather is armed only on takeoff. We had a CQ scenario years ago with an engine failure inside 1000ft, Flaps 35. You had to have a sharp PM that could do the immediate action card items to feather the bad side. It was a challenge/response for pulling back the power lever and the condition lever.
That would be my only guess (outside of it being an Air Berlin type incident). I’ll look back in my Q systems manual, but I’m almost 100% that if you feather them in flight, the plane will give it to you.
CFIscare
Well-Known Member
This was a 72-500 so the condition levers had an auto notch and is subsequently controlled by a knob on the control panel, so they shouldn’t have been touched during flight.*
*if I’m remembering this correctly.
Apophis
Resident Iconoclast
Seems like that would be pretty difficult to do. Not sure about the -500, but on the OG -202/212s I fly, there is a feather gate….you have to lift a lever on the associated condition lever to move past MIN RPM into FTR.
Autofeather is part of the ATPCS system, and it only occurs when the power management rotary selector is in the Takeoff position (normally this is done at my company as part of a flow when the gear comes down). Even in this configuration, you’ll still only get Autofeather when the power levers are above 49 degrees and associated engine torque(s) are above 46%.
So depending on your torque setting during approach, you may or may not get autofeather. You’ll see a green ARM light on the ATPCS push button when it’s available though.
melax
Well-Known Member
Engine problem prior to feather is discussed here.
simpleflying.com
Feathered Propellers Appears To Be Behind January's Yeti Airlines ATR Crash
The latest development comes from analysis of the aircraft’s flight data recorders and cockpit voice recorders.
simpleflying.com
Cherokee_Cruiser
Bronteroc
"Flight data recorder and cockpit voice recorder of the Yeti Airlines ATR-72 aircraft indicates a problem in the engine as the reason behind the crash of the aircraft on 15th January in Pokhara.”
A problem in the engine caused one wing to drop 90 degrees below the horizon and slice into the ground like a knife?
A problem in the engine caused one wing to drop 90 degrees below the horizon and slice into the ground like a knife?
Wardogg
Meat Popsicle
Oof. A demo with pax on board?
Inverted
mmmmmm wine
Well,
I wonder if it is the same as Taiwan. Maybe there was an engine failure and they did feather the wrong engine. Would easily explain why both were feathered.
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