Nepal Plane Crash

[Stevedd32]

Aileronreversal?

As a retired private pilot I am amazed having read pretty much all of this thread but found no reference to what is to me the most likely cause of this crash. Hundreds of single engine pilots over the years have died attempting to do a circuit to land after an EFATO. However many thousands of hours they might have, some are obviously not aware of the fact that IF YOU ATTEMPT A STEEP TURN WHEN FLYING LOW AND SLOW YOU ARE DEAD MEAT!
They assume (presumably due to lack of training) that they only need to apply opposite aileron to level the wings! This is intuitive but fatal. They do not realise that in this situation the drag caused by opposite aileron merely stalls the inside wing promoting a spin.
Google Fairchild B52 crash for a perfect example. You can see the pilot applying opposite aileron (spoilers) as the plane, at 90deg bank spins into the ground.
The key question with regard to the Yeti disaster is, did either the PF or the captain have recent training on incipient spins? Either on a simulator or an aircraft?
All of this assuming of course that there was no defect on the aircraft.

[ATC Watcher]

Originally Posted by michaelbinary

regardless whether procedures were in place or not, the weather on the day looked fine and any professional pilot should be able to execute a visual approach to an airport in those conditions and land safely (assuming no other factors). Also considering most airports in Nepal are VFR they should be well practised in this type of flying.

Absolutely correct, the lack of Ipublished procedures most likely did not play a role, as the flight was VFR performing a visual APP. . The SUP-AIP 2/2023 given by grizzled here is however gives some background on the intoduction of this new airport . That is also what he said. : for background info, not explaining the cause.

@Stevedd32 : interesting but pure speculation ,as we do not know the speed of the aircraft when it (*) starts to turn , and unlike the B52 you refer to, the initial bank we see on this video does not appear to be brutal or excessive , but we'll see what the recorders says.
Note (*) : I say " it" , as, for all we know it could have been uncommanded .

[grizzled]

Originally Posted by michaelbinary

the weather on the day looked fine and any professional pilot should be able to execute a visual approach to an airport in those conditions and land safely (assuming no other factors).

As ATC Watcher clarified, I was not referring to causal factors in this specific accident, I was referring to the infrastructure issues (huge as they are) that are contributing to aviation safety issues in Nepal – including some significant issues regarding the new Pokhara airport.

With regard to the part of your post that I quoted above (my bolding), perhaps therein lies a clue, but we simply don't know yet.

Cheers.

[punkalouver]

Originally Posted by Stevedd32

The key question with regard to the Yeti disaster is, did either the PF or the captain have recent training on incipient spins? Either on a simulator or an aircraft?
.

We already know the answer to this. Incipient spin training is not done. Stall avoidance is trained. The sim likely cannot replicate a spin or an incipient one anyways.

[9 lives]

Stall avoidance is trained.

I opine that avoidance training is of very little use if you're already past avoiding, and well into it!

And, just because I'm curious, would the the "avoiding" being trained be to first reduce AoA and assure that the ball is centered? Or to add power to an already bad situation?

[Yo_You_Not_You_you]

Pokhara International Airport Obstacle .

This is another major obstacle for the airport , I think it is shown on the charts as well , Limiting large airlines there .

[parkfell]

Originally Posted by 9 lives

I opine that avoidance training is of very little use if you're already past avoiding, and well into it!
And, just because I'm curious, would the the "avoiding" being trained be to first reduce AoA and assure that the ball is centered? Or to add power to an already bad situation?

Unstall the wings first by reducing the AoA.

Going slightly off topic, the question arises as to what a student should be exposed to during training for CPL(+IR) issue.
Prior to JAR (1/7/1999) & then EASA, the UK CAP509 training included spinning & at BAeFC, Prestwick
(+ Oxford ~ OATS) aerobatics(dual) were part of the course.
Full exposure at PIK to what the delightful BRAVO AS202 (180hp VP prop) had to offer; a great confidence builder exploring ‘extreme attitudes’.
With JAR that was replaced by stall/spin awareness training, recovering no later than during the incipient stage.
Eventually, EASA introduced mandatory upset training, recognising the shortcomings of ‘awareness training’.

This tragic ATR accident, prima facie, was caused by getting too slow, and not recognising it.
Lack of situational awareness & high workload causing a distraction to the ‘aviating’ aspect of airmanship.

[michaelbinary]

power pitch flags and gear. as a general rule works for just about everything.

I will never ever understand why given that stalling and spinning in on approach to landing is a common accident that spin training was removed from the PPL training.
I think it was just a commercial decision to encourage more uptake in the sport.

And for the life of me I cant understand why 3 - 5 hours upset and unusual attitude revcovery training isnt mandatory for commercial pilots every year.

[ehwatezedoing]

Originally Posted by michaelbinary

And for the life of me I cant understand why 3 - 5 hours upset and unusual attitude revcovery training isnt mandatory for commercial pilots every year.

Maybe because it's better to tackle a problem at its root cause ---> Learn first about not getting yourself into an unusual attitude!

[9 lives]

power pitch flags and gear. as a general rule works for just about everything.

Does this "power pitch...." procedure advocate applying [more] power first to an airplane which already has too high an AoA, and is stalling - making lowering the nose a secondary action!?! So the nose keeps going up as power is applied/increased, and the torque from the power creates an unsymmetrical force on the whole plane, possibly inducing a spin? Why not reduce that AoA, assure the wing unstalls as the priority, then apply power to minimize altitude loss?

[Consol]

Originally Posted by 9 lives

Does this "power pitch...." procedure advocate applying [more] power first to an airplane which already has too high an AoA, and is stalling - making lowering the nose a secondary action!?! So the nose keeps going up as power is applied/increased, and the torque from the power creates an unsymmetrical force on the whole plane, possibly inducing a spin? Why not reduce that AoA, assure the wing unstalls as the priority, then apply power to minimize altitude loss?

I was thought to lower the nose then apply power doing my PPL. On getting a jet job the (senior) instructor taught us that the correct procedure was to hold pitch and apply max power. I said nothing, passed check but kept the real recovery in my head.

[wiggy]

Originally Posted by michaelbinary

And for the life of me I cant understand why 3 - 5 hours upset and unusual attitude revcovery training isnt mandatory for commercial pilots every year.

Mainly what ehwatezedoing said plus that's 3-5 hours of your annual duty hours/annual flying hours you are not available for line flying...........

[Bluffontheriver123]

Originally Posted by Stevedd32

As a retired private pilot I am amazed having read pretty much all of this thread but found no reference to what is to me the most likely cause of this crash. Hundreds of single engine pilots over the years have died attempting to do a circuit to land after an EFATO. However many thousands of hours they might have, some are obviously not aware of the fact that IF YOU ATTEMPT A STEEP TURN WHEN FLYING LOW AND SLOW YOU ARE DEAD MEAT!
They assume (presumably due to lack of training) that they only need to apply opposite aileron to level the wings! This is intuitive but fatal. They do not realise that in this situation the drag caused by opposite aileron merely stalls the inside wing promoting a spin.
Google Fairchild B52 crash for a perfect example. You can see the pilot applying opposite aileron (spoilers) as the plane, at 90deg bank spins into the ground.
The key question with regard to the Yeti disaster is, did either the PF or the captain have recent training on incipient spins? Either on a simulator or an aircraft?
All of this assuming of course that there was no defect on the aircraft.

There are lots of references to what you describe but it is doubtful the crew would be attempting to go much beyond 30 degs of bank. More likely, the steep bank is caused by the stall, both engines are turning, it has hi-AoA, looks a clean wing and if they then used rudder to align and aileron to control bank it would have been a classic skid stall.

Unloading immediately at that altitude is unlikely to have saved them and it is unlikely they will have gone beyond the approach to the stall in training. Paul Ransbury from APS has a bunch of presentations about it from their UPRT sessions on traffic pattern stalls.

APS Traffic Pattern Stalls

[Geriaviator]

Originally Posted by ehwatezedoing

Maybe because it's better to tackle a problem at its root cause ---> Learn first about not getting yourself into an unusual attitude!

Agreed, but HOW do you not get into an unusual attitude if you haven't actually done so? More than half a century ago my ex-WW2 ex-CFS instructor made me spin from every conceivable attitude including an auto-rotation at 500ft on finals. I was shocked when I found out a decade ago that spin training was no longer required for PPLs. An attempt to turn back after engine failure cost the lives of two local flyers last year. I doubt if a commercial airliner could be recovered from the video clip shown but the crew appears to make no attempt to do so. This is not a criticism of them, I wasn't there.

[michaelbinary]

Originally Posted by ehwatezedoing

Maybe because it's better to tackle a problem at its root cause ---> Learn first about not getting yourself into an unusual attitude!

They were professional pilots with many thousands of hours between them, but it didnt work for them did it. I said this many posts ago, you know, 1 pilot flying 1 pilot monitoring.
So being current with the skills to fix imminent stalls etc takes it from a consious mental desision making to a subconsious reaction which is much much faster, which is why people who play top class sports drill routines1000's of times.

Having said that, once the wing dropped they were far too low for any recovery.

[michaelbinary]

Originally Posted by Consol

I was thought to lower the nose then apply power doing my PPL. On getting a jet job the (senior) instructor taught us that the correct procedure was to hold pitch and apply max power. I said nothing, passed check but kept the real recovery in my head.

That was my inaccurate structuring of the sentence. You can apply power and drop the nose at the same time, my bad.

[EXDAC]

Originally Posted by Stevedd32

IF YOU ATTEMPT A STEEP TURN WHEN FLYING LOW AND SLOW YOU ARE DEAD MEAT!

Total BS! I have many many hours racked up at high bank angles in narrow core thermals, some quite close to the ground, and many very close to stall speed. I'm not dead yet. The airpane doesn't know how close to the ground it is and, absent significant wind gradient, it performs just the same at 500 ft as at 5,000 ft.

I also have no concern at all using 45 degree bank in either of the SEP I own and fly. If the yaw string or ball is centered there is no hazard with steep bank angles. If you can't keep the yaw string or ball centered you are dangerous at any altitude and any bank angle with or without an engine.

[michaelbinary]

Originally Posted by EXDAC

Total BS! I have many many hours racked up at high bank angles in narrow core thermals, some quite close to the ground, and many very close to stall speed. I'm not dead yet. The airpane doesn't know how close to the ground it is and, absent significant wind gradient, it performs just the same at 500 ft as at 5,000 ft.

I also have no concern at all using 45 degree bank in either of the SEP I own and fly. If the yaw string or ball is centered there is no hazard with steep bank angles. If you can't keep the yaw string or ball centered you are dangerous at any altitude and an bank angle with or without an engine.

Yes well an ATR isnt a poxy glider or a SEP, and any commercial pilot who wants to keep his job and stay alive wont fly a twin turbo prop slowly with 72 passengers on board at a 45 degree angle of bank, 400 feet off the ground while coming into land.

Oppps sorry, I forgot, they did try to do that and now they are all dead.

I will quite happily fly 90 degrees of bank or more, but my fully aerobatic SEP weighing 1500 lb is nothing like a 49000 lb twin turbo prop ATR 72.

Oh and increasing the bank angle increases the wing loading and that increases the stall speed, and after 45 degrees it increases it a lot faster.

[EXDAC]

Originally Posted by michaelbinary

Yes well an ATR isnt a poxy glider or a SEP, and any commercial pilot who wants to keep his job and stay alive wont fly a twin turbo prop slowly with 72 passengers on board at a 45 degree angle of bank, 400 feet off the ground while coming into land.

The statement I responded to was made by a private rated SEL pilot. The statement I responded to was not aircraft type specific. However, I have no doubt that an ATR is quite capable of 45 degree bank turns wthout loss of control.

[michaelbinary]

Originally Posted by EXDAC

The statement I responded to was made by a private rated SEL pilot. The statement I responded to was not aircraft type specific. However, I have no doubt that an ATR is quite capable of 45 degree bank turns wthout loss of control.

Unfortunately, reality in this case doesnt agree with you does it,

I suggest you offer your services to the investigation team, to point out what the pilots were doing wrong.