ATR72 crash in Nepal 15/01/23

[Thruster88]

2 hours ago, facthunter said:

I think it's just been confirmed the Port engine was slowing down.  NO amount of flying skill could have saved it. Nev

Wouldn't this class of operation, RPT, always fly airspeed and approach or departure profiles to ensure single engine operation. I don't buy the, if the engine fails now we are doomed scenario.   

[red750]

Very reminiscent of this crash immediately after takeoff of TransAsia 235. Just watched the Air Crash Investigation report. In that accident, a faulty torque sensor caused automatic feathering of the starboard propeller and the pilot shut down the wrong 

engine. 

 

[kgwilson]

The ATR 72 doesn't have a particularly draggy airframe when in the dirty configuration as the wheels are contained in the blister under the fuselage & just poke out the bottom, less that single aisle jets like the A320 or 737.

Edited February 7, 2023 by kgwilson

[kgwilson]

5 hours ago, facthunter said:

High wing planes have very draggy undercarriages because of their length. The Fokker F 27 has a rapid retract AIR system to help with the engine out performance and the auto feather is pretty rapid also on all turboprops as they can have more drag that the thrust they deliver if you leave them whirling..

The ATR 72 doesn't have a particularly draggy airframe when in the dirty configuration as the wheels are contained in the blister under the fuselage & just poke out the bottom, less that single aisle jets like the A320 or 737.

[facthunter]

The principle is still there. Flaps wheels  pitch locks out.etc They also went for a change of runway and it may be that both engines were autofeathering it now turns out. That has to be explained WHY and that makes things impossible. 

   Normal approach on most planes is with a fair amount of power on and in strong gusty headwind conditions, a LOT of power.. They fly an approach that is defined by angle. At 10NM you are about 3,000' above the aerodrome if you are on normal profile. You are NEVER in a position to glide unless you've planned it. or got very high/ and or fast. If the failed engine has exterior damage (cowl etc MORE drag) the approach is planned to allow for extra drag and is steeper generally and initiated further away from the aerodrome and the commit point is also adjusted as it may not be able to maintain altitude on one in  those circumstances.  When  you PLAN to use a particular aerodrome you must be able to cover the APPROACH Climb overshoot that covers the engine failure case. Similar to when you are taking off from there. Nev

[facthunter]

There's also the effect of high altitude at the aerodrome. This can make compliance impossible and may be run on a relaxation of  a CAO. (Permit). Like the PK aerodrome charts and figures we operated under in PNG.  PK is described as "developmental" and allows operation at excess weights where the Plane will not stay in the air if an engine out occurred in many places. No wonder a lot of pilots drank a lot..  Nev

[Thruster88]

Simple human errors. Feathered both propellers instead of lowering flap.

 

https://www.flightradar24.com/blog/yeti-airlines-flight-691-preliminary-report-released/

Edited February 17, 2023 by Thruster88

[kgwilson]

Flap was lowered to 30 deg, 23 seconds after both props were feathered and both pilots noticed there was no power coming from the engines (presumably from the CVR data) but it seems neither realised the props had been feathered which seems from the photo of the controls, blindingly obvious. 20,000 and 16,000 hours of experience and it is human factors that raises its head. Everyone makes mistakes and this was the one that created this tragedy.

[Garfly]

 

 

 

[facthunter]

Murphy's Law. It's a lever lock I would say but needs some other precaution so you can't actuate when it will kill you. (Like on approach). Is that the method of shutting down the engines at the end of the day? The props are in the feather position then and until restart. It's a "free spool" engine.  Nev

[RFguy]

1 hour ago, kgwilson said:

Flap was lowered to 30 deg, 23 seconds after both props were feathered and both pilots noticed there was no power coming from the engines (presumably from the CVR data) but it seems neither realised the props had been feathered which seems from the photo of the controls, blindingly obvious. 20,000 and 16,000 hours of experience and it is human factors that raises its head. Everyone makes mistakes and this was the one that created this tragedy.

I dunno . you can have lots of experience  but still not have had good training.

What do they say ? Practice makes Permanent... Not 'practice makes perfect'.

[facthunter]

NEVER move a control on a plane "instinctively".. Tiredness or over familiarity make for doing things without fully thinking about it. It IS HUMAN factors at some level. There was nothing "wrong" with the plane. I know of a few similar instances and people say I have NO IDEA why I did that.   Nev

Edited February 18, 2023 by facthunter

[onetrack]

The training level here is obviously pretty poor. What happened to the pilot monitoring? There was a double failure here, one pilot made a stupendous, inexplicable error, and the monitoring pilot also failed to pick it up.

Surely, with both props brought to feather, the power loss/airspeeed loss would be instantly noticeable? There was no monitoring going on, to lose both power and airspeed, with neither pilot noticing anything wrong.

[facthunter]

IF you are acting the" One Man Band" why have two pilot's?  IF you were intentionally feathering it would not be to TWO engines at once either and you would do something like Power Loss No1, Confirm. Engine NO 1.  Move to feather.  Auto feather is locked out of the second engine.

[Bosi72]

Two captains, both accustomed to fly from the left seat. 

 

Engine failure memory checklist when they were endorsed for twins would save them: Mixture Up, Pitch Up, Power Up, Gear Up, Flaps Up, Identify, Verify, Feather..

 

Since no Mixture in ATR, Pitch Up would likely get them out of troubles.

[facthunter]

Pitch on turbines is very different. You have overspeed locks, Flight fine/ ground fine locks Auto coarsening for overspeed protection (Allison) which idles at the same speed as it runs. A turbo prop Prop can absorb 3 or more times the Power it develops. IF it runs amok. IF you overpitch it the turbine temp goes up Fast. Overtemping is more likely on start up. Fitment of Auto Feather is very normal. and it's quick because it has to be..   Nev

[kgwilson]

Both pilots were very experienced and knew very well how to fly and land this aircraft. Mitigating factors of the change of runway, new airport, checkride process and the mistake of feathering both engines in the landing configuration and then not recognising what had been done by both had the holes in the proverbial Swiss Cheese well and truly aligned.

[derekliston]

ATR doesn’t have the long undercarriage as per the Dash8/Q400 since the wheels retract into sponsons (is that the word?) but at slow speed and dirty I think they would have to be on the ball feathering the prop to avoid trouble!

[facthunter]

I can't see that doing it deliberately was ever part of the equation. It obviously had plenty of fuel on board.  In flight fuel exhaustion would require props be feathered to extend the glide, but THAT is not the situation here.  The engines were still running but the blades were 90 degrees to where they would do anything to make thrust.  Nev

[derekliston]

It can be quite frightening really. If you watch for example Mentour Pilot to see the number of high time professional pilots who make quite basic mistakes! Won’t stop me travelling by air but you just have to walk into that aluminium tube and hope for the best!

Edited February 18, 2023 by derekliston
Spelling error, fat finger syndrome!

[facthunter]

The seat up the front is where you have the best fighting chance.  Nev

[old man emu]

On 16/01/2023 at 6:38 PM, facthunter said:

You can clearly see the aileron being applied to lift the dropping wing. It's all over at that stage.  Nev

Didn't I hear something in a discussion video about using aileron to lift a dropping wing when close to the ground. But that only applied to Ag pilots, so I'm led to believe.

[facthunter]

I can't see it being a good idea for anyone.. Never heard of  it being recommended. Only the opposite.    Nev.

[Student Pilot]

On 18/2/2023 at 2:48 PM, old man emu said:

Didn't I hear something in a discussion video about using aileron to lift a dropping wing when close to the ground. But that only applied to Ag pilots, so I'm led to believe.

Never heard that

 

[Carbon Canary]

ATR prop condition and flaps levers side by side. Full feather and flaps 30 lever movement would be very similar.

 

If you were distracted by new airfield approach, tired, etc, may be easy enough to swing the wrong lever by memory feel rather than positively identifying what you had your hand on.