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bueb0g
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TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 12:48 pm

I thought it might be nice to have a more focused, less messy discussion than the civav one here on the accident. We all know how useless those threads get. If mods think this is inappropriate or that all discussion should be directed towards the civav thread, please remove.

http://www.youtube.com/watch?v=hDshs7trY-I&feature=youtu.be

What exactly does everyone think we are seeing here?

In my reckoning, the video opens with the aircraft gliding, apparently under control. The left prop seems feathered, the right prop seems to be turning. The rear of the fuselage appears to contact, or almost contact, a building. The aircraft then banks left - left wing stalling? - and clips the bridge, before exiting the frame.

Some have said that the aircraft clipped a building with a wing/horizontal stabiliser before crashing but I see no evidence of that.

Another video that seems to show the moment of departure from controlled flight:

http://www.youtube.com/watch?v=q3iOVtRMwEk

Does this indeed look like a stall, or rather a bank to avoid obstacles?

The primary question appears to be, that if the left prop is stopped and the right is turning, why is the aeroplane losing height? If the right engine is also not delivering thrust, why is the prop not feathered?

Avherald article for updates:
http://avherald.com/h?article=48145bb3&opt=0

Live feed of the recovery operation:
http://www.youtube.com/watch?v=T8GmxMGCDh4&feature=youtu.be
Roger roger, what's our vector, victor?
 
rcair1
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 3:38 pm

Quoting bueb0g (Thread starter):
In my reckoning, the video opens with the aircraft gliding, apparently under control. The left prop seems feathered, the right prop seems to be turning. The rear of the fuselage appears to contact, or almost contact, a building. The aircraft then banks left - left wing stalling? - and clips the bridge, before exiting the frame.

I agree though I'm not sure I would use the term "gliding". What I see is, I believe:
- A controlled descent. Controlled in that the a/c is in control, not stalled. (controlled does not mean 'desired'). However, it could be stalled (even deep stall on a t-tail?) but in a wings level attitude.
- I do not see evidence of any real or significant contact with a building.
- The sudden bank - I think - is indicative of the left wing stalling which is why I believe the descent prior is not a stall.
- I don't believe the sudden bank is an evasive maneuver as some have proposed for the following reasons: 1) A pilot in that situation would be going for wings level, nose high, belly impact. 2) If you look at the google street view at the scene, there are no obstacles that would cause a left turn. 3) if he were trying for the river - he would turn right, not left.
- I cannot tell if #1 is feathered, rotating slowly, rotating rapidly.
- #1 prop is present - no obvious indication of a prop failure from the video.
- I cannot tell what the control surfaces or flaps were doing
- I think I see a low pressure induced cloud on the right side of the fuselage as they strike - that would not be surprising in those conditions - nor particularly important except it shows the aircraft was moving sideways relative to the air-stream.

Of course, what I'm doing is describing what I see - which may have little relation to what happened. They have the recorders. Let's see what they say.

What we know - from the videos/reports
- They took off.
- They (reportedly) declared an emergency(*) with #1 engine failure.
- They were in a wings level, nose high, descent.
- At an altitude in the order of 150 ft above highway (using the wingspan as a ruler) they started a rapid roll left to what was 90 degrees by the time they hit the highway.
- The gear was up.

(*) Note - the media reports state they called "mayday". In my experience, the more typical language for a 'normal' failed engine would be to declare an emergency. "xxx is declaring an emergency". "mayday" is more indicative of a situation that is beyond a "normal" emergency. Then again - the press could be using the word "mayday" to describe declaring an emergency.

If #1 had failed (as reported) and was not feathered (for whatever reason), I'm not sure the ATR can continue - at least at low speed. A non-feathered prop is a giant brake.

I would be interested in hearing from an ATR pilot if the ATR 72 can maintain altitude SE with a non-feathered prop.
rcair1
 
CplKlinger
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 3:40 pm

From the looks of it being nose high in some of the videos, it looks like it's already right on the edge of the stall envelope, and something happens to cause that left wing to stall. I can't make our if that left engine is providing power, but I'd hazard a guess that it isn't and the asymmetrical thrust causes the left wing to stall out and they go over, at least based on the way that the wing drops. They likely know they were in trouble and were fighting to keep it gliding, but aerodynamics won the fight
 
Whiteguy
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 4:00 pm

Quoting rcair1 (Reply 1):
(*) Note - the media reports state they called "mayday". In my experience, the more typical language for a 'normal' failed engine would be to declare an emergency. "xxx is declaring an emergency". "mayday" is more indicative of a situation that is beyond a "normal" emergency. Then again - the press could be using the word "mayday" to describe declaring an emergency.

Not necessarily, both airlines I've worked for have trained to use the words "Mayday". Don't mess around, get everyone's attention. Flying around at low level, single engine in a transport type aircraft is not normal!
 
rcair1
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 4:07 pm

Quoting whiteguy (Reply 3):
Not necessarily, both airlines I've worked for have trained to use the words "Mayday".

Great - thanks for that! I may be reading too much into a word choice - that may not even be accurate. I fly SE - so an engine loss is certainly a mayday situation for me!
rcair1
 
bueb0g
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 4:37 pm

Quoting rcair1 (Reply 1):
(*) Note - the media reports state they called "mayday". In my experience, the more typical language for a 'normal' failed engine would be to declare an emergency. "xxx is declaring an emergency". "mayday" is more indicative of a situation that is beyond a "normal" emergency. Then again - the press could be using the word "mayday" to describe declaring an emergency.

In most of the world, pilots won't say "declaring an emergency", but "mayday" or "pan-pan"; saying "emergency" is normally seen as an american thing, and is seen as synonymous with mayday in the rest of the world.

I agree with your conclusion that the bank is uncontrolled.

Quoting CplKlinger (Reply 2):
From the looks of it being nose high in some of the videos, it looks like it's already right on the edge of the stall envelope,

Agreed. It looks very near stalling.

http://www.youtube.com/watch?v=lYczDsj0ATI#t=19

New, longer video - looks like both props are stopped.

[Edited 2015-02-04 08:42:04]

[Edited 2015-02-04 08:42:17]
Roger roger, what's our vector, victor?
 
AIRWALK
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 4:45 pm

Mayday signals distress while a pan call signals urgency.

If the aircraft was struggling to maintain height they would use a Mayday however in a typical situation where climb-out performance is affected but still not critical, a pan-pan call could be used which signal that an aircraft is in difficulties which compel it to land but they pilot does not need immediate assistance.

Quoting rcair1 (Reply 1):
the media reports state they called "mayday"

Starlionblue posted a link to the ATC recording in the other thread I think which had them calling a Mayday
I'm sure this thread will take off soon
 
TheSonntag
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 5:00 pm

I do not know whether this is really totally accurate (seems so however), but in this case they were using "mayday":

https://www.youtube.com/watch?v=9KhZwsYtNDE
 
Woodreau
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 5:10 pm

An ATR-72-600 is certified under JAR 25,so it is required to be able to maintain a positive climb gradient with an engine inoperative.

Just looking at the video, it looks like a VMC roll to me.
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
 
CplKlinger
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 5:39 pm

Quoting bueb0g (Reply 5):
New, longer video - looks like both props are stopped.

I think that's a trick of the camera. The left definitley looks stopped, but the right I'm not so sure about. Curious that you don't hear any noise, as I'd imagine an ATR that close, even on the highway ought ot be a bit loud.
 
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flylku
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 11:34 pm

I thought that most turboprops have some sort of auto feather but confess to knowing nothing about proceduraly how this would work.
...are we there yet?
 
hivue
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 11:35 pm

In case of an engine failure in an ATR 72 how much (if any) of the procedure is handled automatically besides feathering? Could they have accidentally shut down the non-affected engine?
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
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Starlionblue
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RE: TransAsia ATR Crash, Techops Discussion

Wed Feb 04, 2015 11:35 pm

Quoting rcair1 (Reply 1):
(*) Note - the media reports state they called "mayday". In my experience, the more typical language for a 'normal' failed engine would be to declare an emergency. "xxx is declaring an emergency". "mayday" is more indicative of a situation that is beyond a "normal" emergency. Then again - the press could be using the word "mayday" to describe declaring an emergency.

Having trained on both sides of the pond, I get the sense that in Europe there is a bias towards "mayday" and "pan pan" (pure ICAO phraseology), while in the US there is a bias towards "declaring an emergency".

Quoting AIRWALK (Reply 6):
Quoting rcair1 (Reply 1):
the media reports state they called "mayday"

Starlionblue posted a link to the ATC recording in the other thread I think which had them calling a Mayday

The call is at the 23m24s mark.

http://archive-server.liveatc.net/rcss/RCSS-Twr-Feb-04-2015-0230Z.mp3
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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BreninTW
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 1:04 am

Quoting rcair1 (Reply 1):
2) If you look at the google street view at the scene, there are no obstacles that would cause a left turn.

I'm going to post the same answer to this as I did in the CivAv topic. This is not to claim that the pilot intentionally turned to the left, but to explain why turning to the right would very likely led to a much worse outcome.

Quoting rcair1 (Reply 124):
If the pilot were trying for the river - would have turned right, not left.

If the pilot had turned to the right, there would have been some very tall office buildings in the way (depending on when the right turn was initiated), a different road bridge over the river, a very large parking lot, and the terminus of the Taipei Metro system. Oh, and a very, very large tent full of school children -- think Cirque du Soleil tents.

Bascially the aircraft managed to crash between two bridges in about the only area that didn't (for all intents and purposes) guarantee 100% fatality on the aircraft and multiple fatalities on the ground.

There are no two ways about this: We were very, very fortunate yesterday that there were not many more casualties.
 
celestar
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 1:36 am

Quoting rcair1 (Reply 1):
I agree though I'm not sure I would use the term "gliding". What I see is, I believe:
- A controlled descent. Controlled in that the a/c is in control, not stalled. (controlled does not mean 'desired'). However, it could be stalled (even deep stall on a t-tail?) but in a wings level attitude.
- I do not see evidence of any real or significant contact with a building.
- The sudden bank - I think - is indicative of the left wing stalling which is why I believe the descent prior is not a stall.
- I don't believe the sudden bank is an evasive maneuver as some have proposed for the following reasons: 1) A pilot in that situation would be going for wings level, nose high, belly impact. 2) If you look at the google street view at the scene, there are no obstacles that would cause a left turn. 3) if he were trying for the river - he would turn right, not left.
- I cannot tell if #1 is feathered, rotating slowly, rotating rapidly.
- #1 prop is present - no obvious indication of a prop failure from the video.
- I cannot tell what the control surfaces or flaps were doing
- I think I see a low pressure induced cloud on the right side of the fuselage as they strike - that would not be surprising in those conditions - nor particularly important except it shows the aircraft was moving sideways relative to the air-stream.

I 100% agree with what you had stated.
I too, did not see an intentional avoidance on banking left. To BreninTW point, there are building on the right of the flight path, but given the 'faulty' engine is a left one, as we all seem to agree at this point, turning right would not be feasible.

Quoting Woodreau (Reply 8):
Just looking at the video, it looks like a VMC roll to me.

I am sorry but what is the full meaning of a VMC roll?

Quoting CplKlinger (Reply 9):
I think that's a trick of the camera. The left definitley looks stopped, but the right I'm not so sure about. Curious that you don't hear any noise, as I'd imagine an ATR that close, even on the highway ought ot be a bit loud.

I think you did not hear any loud noise if that the video is being taken by camera mounted inside of the car while travelling on a stretch of express way localled called HuangDong Viaduct. Pollution is pretty bad in Taipei, most car run with window closed and air-con on. So, guess it would not be possible to hear much of a noise then!
 
Alias1024
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 3:57 am

Quoting Woodreau (Reply 8):


Just looking at the video, it looks like a VMC roll to me.


Agreed. It takes me back to my flight instructing days demonstrating Vmc to multiengine students. It may be a stall and incipient spin, but it sure looks like a Vmc roll.
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CplKlinger
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 11:31 am

Quoting hivue (Reply 11):
Could they have accidentally shut down the non-affected engine?

Wouldn't be the first time that has happened in an emergency situation (Kegsworth, the C-5 in DE that has the wrong engines pulled to idle).
 
DashTrash
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 3:13 pm

Quoting flylku (Reply 10):
I thought that most turboprops have some sort of auto feather but confess to knowing nothing about proceduraly how this would work.

I can't say for certain in the ATR, but in a Dash 8 (same engine, different prop I think), the AFX system activates when the system is selected, arms at a certain power lever angle, and engine oil pressure drops below a certain PSI. The system will feather the prop. It's been 8 years since I went through a recurrent on the airplane so my memory might be fuzzy.

In practical terms, it's a system that feathers the prop in the event of an engine failure. An unfeathered prop in a big turboprop is a big deal.

Quoting celestar (Reply 14):

I am sorry but what is the full meaning of a VMC roll?

It is when you run out of rudder authority and the aircraft rolls over due to asymmetric thrust and lift.

I hate guessing on accidents, but what appears to be VMC induced roll here could have been caused by any number of things. The aircraft should be able to maintain some climb even with an unfeathered prop if the single engine profile is flown, but it is physically challenging until the prop is manually feathered.

There is also the possibility that there was a loss of prop control resulting in an over or under speed condition, or possibly the prop went into ground range. At low altitude a prop going into ground range is generally fatal. Especially if you're at a high angle of attack and initial torque setting at the time of upset.
 
hivue
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 4:24 pm

Quoting Woodreau (Reply 8):
Just looking at the video, it looks like a VMC roll to me.
Quoting Alias1024 (Reply 15):
It may be a stall and incipient spin, but it sure looks like a Vmc roll.
Quoting DashTrash (Reply 17):
Quoting celestar (Reply 14):
I am sorry but what is the full meaning of a VMC roll?
It is when you run out of rudder authority and the aircraft rolls over due to asymmetric thrust and lift.

In the case of going below Vmca and the airplane rolls will it have the same roll rate limits as if the roll had been commanded in controlled flight? I think some observers are saying the airplane is rolling much faster than could ever be commanded by a pilot or AP in controlled flight. If true I would think this would strongly suggest the roll was caused by the left wing stalling.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
Woodreau
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 7:11 pm

A Vmc roll is not the same thing as a stall.

Depending on the altitude, Vmc will occur first before the aircraft stalls. At higher altitudes, the aircraft will stall before reaching Vmc,

The asymmetric thrust causes a yaw condition, not a roll. Below Vmc, the rudder does not have the authority to prevent the yaw caused by the asymmetric thrust. The wing with the operating engine will generate more lift due it being "pulled" forward (around the cg) due to the yaw, and the propeller slipstream of the operating engine provides additional airflow over the wing which increases the lift on that wing. The imbalance of lift between the two wings is what causes the Vmc roll.

More info regarding Vmc roll page 12-27 to 12-30.

https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-5of7.pdf
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
 
hivue
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 7:36 pm

Quoting Woodreau (Reply 19):

OK, I see. Thanks.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
Alias1024
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 8:02 pm

Quoting DashTrash (Reply 17):
There is also the possibility that there was a loss of prop control resulting in an over or under speed condition, or possibly the prop went into ground range. At low altitude a prop going into ground range is generally fatal. Especially if you're at a high angle of attack and initial torque setting at the time of upset.

That's an interesting thought. It would certainly explain why they couldn't maintain altitude on one engine, and make the aircraft far more difficult to control.
It is a mistake to think you can solve any major problems with just potatoes.
 
Pihero
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 8:42 pm

Good idea, this thread here.
Copied from the civav thread :

Trying to get away from the blatant ethnophobia, bias and *the pilot dun it* nonsense.

ENGINE FLAMEOUT
This in itself is a non event, the most practiced exercise in an airline pilot's life.
Get the plane flying, clear the obstacles... Engine relight procedure... End of story.
But it wasn't.
The only problem with that procedure is that one has to select MCT to get the propeller out of feather in the case of an auto feather.
On the numerous pictures, Prop # 1 seems to be rotating, but at a coarser pitch than # 2.

A simple flameout seems to be too... simple.

STALL
Considering the FR24 readouts, it seems likely, but just...
In this condition, there are a few handling problems :
If roll control application of a desired roll to the right :
- On the left wing, with the aileron down, that wing stall will be made worse ( increased AoA due to increased chord curvature)... the stall is accentuated.
- On the right wing, reduced lift due to the spoiler extension and the up aileron movement and increased drag, but not enough to straighten the attitude / roll combination.
The result is in fact even less lift / drag ratio, increasing the downward flightpath.

VMCA
Once again, it should have been controlled quite easily, with just a few degrees of bank toward the right engine... and then the power of that engine should have been enough to accelerate away...
But it didn't happen.

The propellers different pitches seem to tell the story of an unmanageable handling situation : too much power to the right engine and it's a left spiral... not enough power to the right engine and the flight path is downward.
That seems to be the illustration of the last minute videos.
Contrail designer
 
rcair1
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 05, 2015 11:44 pm

Quoting Pihero (Reply 22):
A simple flameout seems to be too... simple.

   This is something that is so basic for twin ops that the pilots should handle it just fine.

Quoting Pihero (Reply 22):
The propellers different pitches seem to tell the story of an unmanageable handling situation : too much power to the right engine and it's a left spiral... not enough power to the right engine and the flight path is downward.
That seems to be the illustration of the last minute videos

Agreed. In the latest videos that are slowed down (haven't bothered to try to capture them and edit myself) it seems like #1 is rotating faster than it should be for full feather.

However, one thing piece of data that kind of surprised me.
I wondered what the descent rate really was.
Based on the FR24 data (and I won't vouch for that), I did a simple calculation of the descent rate for the last 114 seconds.

I started at 02:30:06 UTC and 1350 ft
I then calculated the delta in seconds for each data point and the delta in altitude.
I converted that to ft/s and ft/m.
Unless I did something really stupid - the descent rate is not that high.
There was an initial rapid descent - but it flattened out.

Of course - this is VERY course data - but if you put big error bars on it you can see a basic 'rate'.

Here is my data - feel free to check and correct and tell me if I'm full of hot air.

TimeDelta(s)Altitudef/sf/m
61350
137135000
1961250-100-1000
2671000-250-2143
348825-175-1313
417725-100-857
476625-100-1000
547575-50-429
606500-75-750
8121300-200-571
11433200-100-182
rcair1
 
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BreninTW
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 12:09 am

My partner made an interesting observation, which may (or may not) lend credence to the theory that the pilot was trying to ditch: The area where they crashed is the widest part of the Keelung river.

There was also a picture published in one of the local news media that showed the aircraft's path and it essentially flew along the river for the last part of the flight.
 
celestar
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 4:51 am

Dear BreninTW, do you not find it strange that the MayDay call was at the very last few seconds of the crash, or right before the actual crash? It seems the pilots were busy fighting to control the plane once took off but did not radio back on what was the condition there? I am not so sure about local media stating the heroic act of the pilots to avoid buildings but I hope that is his intent but I am not too convinced. I too saw the local newsapaper about the path the plane took before ditching. But seeing the last few seconds of the crash, I am convinced personally that it was a total loss of directional control though the pilots may want to have the intention to ditch.
 
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BreninTW
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 8:29 am

Can anyone make sense of this image that KarelXWB posted over in CivAv?

http://pbs.twimg.com/media/B9JarHTIAAAgAy3.jpg:large

https://twitter.com/FlightDKM/status/563612601029263360
 
mmo
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 9:36 am

Quoting BreninTW (Reply 26):
Can anyone make sense of this image that KarelXWB posted over in CivAv?

In a nutshell, the crew shut down the L (#1) engine while the R (#2) engine did an auto shutdown.

On Feb 6th 2015 Taiwan's ASC reported that the investigation so far determined from flight data and cockpit voice recorders: the aircraft received takeoff clearance at 10:51Z, in the initial climb the aircraft was handed off to departure at 10:52:33Z. At 10:52:38Z a master warning activated related to the failure of the right hand engine, at 10:52:43Z the left hand engine was throttled back and at 10:53:00Z the crew began to discuss engine #1 had stalled. At 10:53:06Z the right hand engine (engine #2) auto-feathered. At 10:53:12Z a first stall warning occured and ceased at 10:53:18Z. At 10:53:19Z the crew discussed that engine #1 had already feathered, the fuel supply had already been cut to the engine and decided to attempt a restart of engine #1. Two seconds later another stall warning activated. At 10:53:34Z the crew radioed "Mayday! Mayday! Engine flame out!", multiple attempts to restart the engines followed to no avail. At 10:54:34Z a second master warning activated, 0.4 seconds later both recorders stopped recording.


Source: http://avherald.com/h?article=48145bb3&opt=0

Would appear to be another Kegworth.
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bueb0g
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 11:22 am

Seems like the final roll was a stall and not a VMC roll then, and most of the descent was indeed done with little or no power.
Roger roger, what's our vector, victor?
 
mmo
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 12:19 pm

If we weren't all crazy we'd all go insane!
 
rcair1
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 3:18 pm

My interpretation of events is as follows.
This is not any kind of official analysis.
Time (approximate)Engine 1 (Left)Engine 2 (right)Comments
2:52:33RunningFlame out warning Aircraft climbing
2:52:41RunningFuel flow zeroRight engine has failed, feathered (auto?), but fuel is still on.
RunningFeathered (auto)
2:52:43RunningAuto restartAuto restart continues to end of flight
2:53:05Throttle reducedAuto restartThrottle on #1 is pulled back
2:53:00Throttle 0%Auto restartBoth engines producing no thrust. Descent starts
2:53:23Fuel Shut offAuto restartDescending
2:53:27Auto restartAuto restartDescending
2:54:18Fuel OnAuto restartDescending
2:54:23Engine startingAuto restartDescending
2:54:29Coming out of FeatherAuto restartDescending


[Edited 2015-02-06 07:33:40]
rcair1
 
hivue
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 3:20 pm

Quoting mmo (Reply 27):
In a nutshell, the crew shut down the L (#1) engine while the R (#2) engine did an auto shutdown.

There are SOPs that are supposed to handle this sort of thing, right? I've seen videos where there is a simulated engine failure, and during the emergency procedures the PM puts his hand on the good fuel cutoff, throttle (or whatever is applicable) to guard it. If the PF and PM reach for the same control they know someone is confused.

Of course, if they're both confused...

[Edited 2015-02-06 07:21:42]
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
mmo
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 9:09 pm

Quoting hivue (Reply 31):
There are SOPs that are supposed to handle this sort of thing, right?

Reading the transcript, it looks as if the left engine was shut down without any coordination. It was drilled into my head over 40 years ago, you don't do anything in a hurry. First thing is wind your watch. In this case, it would appear as if the SOPs were not followed, assuming the CVR transcript is accurate.
If we weren't all crazy we'd all go insane!
 
hivue
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RE: TransAsia ATR Crash, Techops Discussion

Fri Feb 06, 2015 9:19 pm

Quoting mmo (Reply 32):
First thing is wind your watch.

Great advice for a lot of situations outside of aviation as well.  
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
LTC8K6
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RE: TransAsia ATR Crash, Techops Discussion

Sat Feb 07, 2015 5:37 am

http://www.youtube.com/watch?v=RUQWJai59lo

Video from a building showing the sink rate.
 
OMP777X
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RE: TransAsia ATR Crash, Techops Discussion

Sat Feb 07, 2015 6:30 am

Quoting LTC8K6 (Reply 34):
Video from a building showing the sink rate.

That must've been absolutely and utterly terrifying for everybody on board at that point. I cannot even imagine what was going through their minds at the point when they went into the roll, let alone while they sank at an intense rate like that. May the survivors somehow manage to make a full recovery, and may those who've perished rest in peace.

Best,

OMP777X
"Happy Flighting!"
 
OMP777X
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RE: TransAsia ATR Crash, Techops Discussion

Sat Feb 07, 2015 9:08 am

Transasia has cancelled over 80 flights per day in order to immediately retrain their ATR pilots. I'm unaware of this course of action ever being taken by an airline in response to an accident (grounding them for retraining until tests are passed, when the individual pilots have done no wrong), especially so soon, but they seem to fear another accidental engine shutdown would be imminent.
http://www.dailymail.co.uk/wires/afp...pilot-retraining-deadly-crash.html

Best,

OMP777X
"Happy Flighting!"
 
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BreninTW
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RE: TransAsia ATR Crash, Techops Discussion

Mon Feb 09, 2015 12:13 am

Quoting Omp777x (Reply 36):
I'm unaware of this course of action ever being taken by an airline in response to an accident

To understand this, I think you need to understand the Taiwanese public's perception of TransAsia at this stage. If GE wasn't seen to do something to "improve safety," the Taiwanese public would simply stop flying GE because the airline would be perceived as being unsafe and unwilling to do anything about that. It's already happening to some degree -- but a perceived lack of action would result in an almost absolute refusal to book/fly on GE.

So, as with the government's grounding of the AT7 earlier, there has to be the impression created that concrete steps are being taken to improve safety.

This action was not borne out of any worry that another set of pilots is going to be doing the same thing in the near future, it's driven by pure PR and impression creation/management.

Shortly after the MaKong (PengHu) accident, my partner had a business trip to KNH, it took a lot of reassurance from me that flying GE was safe before he would book the GE flights. After this accident, the chances of setting up a successful ice-skating rink in Hades are better than the chances of getting him on another GE plane.

It's all about perceptions.
 
DashTrash
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RE: TransAsia ATR Crash, Techops Discussion

Mon Feb 09, 2015 2:12 pm

Quoting hivue (Reply 31):
There are SOPs that are supposed to handle this sort of thing, right?

Yes.

Dated and different turboprop airliner specific, but each engine abnormal start the same.
PF calls for max power, PNF verifies max power is set automatically via the uptrim, or if required, and replies that max power is set. Then the gear is verified up. Each scenario begins the same, and branches off accordingly.

PF calls for the problem's identity. There are a few possibilities here: L/R engine failure, with/without autofeather, L/R engine failure with/without fire, ECU failure. PNF will reply with the applicable abnormal. With an ECU fail, the PF will call for the PNF to restore torque (approximately a 30% drop in output as the HMU takes over).

For an engine failure, no fire, and feathered prop, the PF will fly the single engine profile til reaching acceleration altitude, then after cleaning up the airplane, will call for the engine to be shut down. During the shutdown, which we refer to as one of the memory items, the PNF will put his hand on the affected power lever, and state what he is going to do it "#1 power lever - flight idle. Confirm?" PF will look at where the PNF's hand is and confirm or correct. This sequence happens for any engine control change during an engine shutdown.
 
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Web500sjc
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RE: TransAsia ATR Crash, Techops Discussion

Mon Feb 09, 2015 7:30 pm

Quoting DashTrash (Reply 38):

Just to add, the first thing brought back is the power lever- that in its self is a verification of the correct engine. It's much easier to fix a idle power lever than Restarting an engine or unfeathering the engine.
 
DashTrash
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RE: TransAsia ATR Crash, Techops Discussion

Tue Feb 10, 2015 2:35 pm

Quoting web500sjc (Reply 39):
Just to add, the first thing brought back is the power lever- that in its self is a verification of the correct engine. It's much easier to fix a idle power lever than Restarting an engine or unfeathering the engine.

Very true.

In a turboprop the gauges will indicate the failed engine unlike a piston, but pulling the affected power lever back is verification you have the correct engine. I think we even called out "no change", but might be confusing that with a different airplane / company.

Not sure about other airlines, but we had no relight procedures at my company. If you shut it down, it stayed shut down.
 
michi
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RE: TransAsia ATR Crash, Techops Discussion

Tue Feb 10, 2015 3:43 pm

Quoting DashTrash (Reply 40):
Not sure about other airlines, but we had no relight procedures at my company. If you shut it down, it stayed shut down.

There have been studies about that matter. Most of the time, when an engine fails at a high power setting, something is damaged and a relight will be most likely unsuccessful. It was determined that this is accurate for +90% of all high power engine failures.
 
LTC8K6
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RE: TransAsia ATR Crash, Techops Discussion

Tue Feb 10, 2015 5:12 pm

10:41:15 The recording begins.

10:51:13 The control tower at Taipei Songshan airport authorizes takeoff.

10:52:01 approximately, the aircraft takes off [begins takeoff roll, apparently].

10:52:38 Master warning for No. 2 engine, a few hundred meters from the runway.

10:52:42 No. 1 engine is throttled down.

10:53:00 A crew member mentions engine shutdown procedures.

10:53:06 A crew member mentions throttling down the No. 1 engine.

10:53:08 A crew member confirms No. 2 engine flameout.

10:53:10 Stall warning.

10:53:13 Stall warning.

10:53:20 A crew member mentions feathering and stopping fuel supply to No. 1 engine.

10:53:21 Stall warning.

10:53:24 No. 1 engine is shut down.

10:53:26 Stall warning.

10:53:35 A crew member calls “Mayday mayday mayday. Engine flameout.”

10:53:56 Stall warning.

10:54:06 Stall warning.

10:54:09 A crew member mentions engine restart.

10:54:12 Stall warning.

10:54:20 [Attempted] restart of No. 1 engine.

10:54:23 Stall warning.

10:54:34 Master warning.

10:54:37 The recording ends.

http://aviationweek.com/commercial-a...d-procedures-focus-transasia-probe
 
ThirtyEcho
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RE: TransAsia ATR Crash, Techops Discussion

Thu Feb 12, 2015 3:26 am

Everybody in the government but the Minister of Shrimp Farming has felt free to make comments to the press about suspected causes for the accident, well in advance of any official report. Even without a cause being determined, the government has prescribed remedial retraining of flight deck crews, assuming pilot error to be a factor. Such is the state of things in a dictatorship.

I can well imagine a causal chain, that has nothing to do with flight crew error, that lead to this disaster. The research on this point will have to be done in a real airplane by test pilots and not in a simulator.
 
Tommy525
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RE: TransAsia ATR Crash, Techops Discussion

Thu Jun 18, 2015 5:01 pm

Looks like it was a mistaken shut down of engine 1, the one that was working. LIkely because of a prior problem with that engine. But it was number 2 that was not working right. Leaving them with zero working engines.

Wonder when the official accident report will be out.
 
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larshjort
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RE: TransAsia ATR Crash, Techops Discussion

Sun Jun 21, 2015 8:20 am

Quoting tommy525 (Reply 44):

In a year or two I would think.

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