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TransAsia in the water?

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TransAsia in the water?

Old 6th Feb 2015, 19:32
  #321 (permalink)  

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#326

Bill K

What needs to be mentioned is that having lost power, they failed to maintain a safe speed. If memory serves, the aircraft stalled and entered an incipient spin. It was also above MTOM so even if it had been correctly handed, its climb performance would have been somewhat limited at best. Not Performance A

Easy to say after the event, but a force landing ahead would have been the answer. This of course goes against the grain with a multi engined aircraft.

Last edited by parkfell; 6th Feb 2015 at 20:50. Reason: Xref
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Old 6th Feb 2015, 19:57
  #322 (permalink)  
 
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olasek:

Engine data readout.
Not familiar with these systems or procedures.

When No2 engine fails, the No1 engine bleed immediately trips off. Why would this be? It seems very coincident.

Is this to give more power to the live engine?

Last edited by silverstrata; 6th Feb 2015 at 21:45.
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Old 6th Feb 2015, 20:08
  #323 (permalink)  
 
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Closing the bleed valves allows the engine to produce max power - which is generally handy when you've just lost half your available thrust.

Any theories as to the ~3 sec delay between the increase on #1 and autofeather on #2? A previous poster said 'normal', then corrected himself to say only when WOW... I also recall reading that somewhere myself. WOW appeared to be sensing correctly on the FDR.

#2, from the data on the trace, appeared to be running just fine until it decided to autofeather - thereafter it appeared to continue to run just fine, although at 'idle' and prop feathered.

There's more than one mystery here to solve I believe. Why #2 AFd in the first place, and why someone / something shut down #1.
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Old 6th Feb 2015, 20:15
  #324 (permalink)  
 
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There's more than one mystery here to solve I believe.
Why #2 AFd in the first place,
and why someone / something shut down #1.
One hopes that the investigation board will agree with your root cause outline there. Absent #2 acting abnormally, the decision to mess with either engine never arises. If it can happen to one crew it can happen to another one.
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Old 6th Feb 2015, 20:24
  #325 (permalink)  
 
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In reply to post #311, regarding the ATPCS; autofeather is activated on the affected engine 2.15 seconds on the ground or in flight.
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Old 6th Feb 2015, 20:37
  #326 (permalink)  
 
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Two captains,even three might be present at simulator sessions. So it shouldn`t be a problem in everyday cockpit. If then,there are not some other things we don`t know about.
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Old 6th Feb 2015, 20:46
  #327 (permalink)  
 
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New video from the top of a nearby building:

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

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Old 6th Feb 2015, 20:50
  #328 (permalink)  
 
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First of all, praise is due the investigators for timely release of at least some of the FDR parameters. They stand well above their Indonesian counterparts

The graphs show fluctuating torque readings in both engines. If this apparent state of affairs is validated, one can only imagine the confusion in the cockpit.

Master Warning and Beta come up for 2 and ITT2/FF2 drops at close to the same time which is indicative of autofeather 2 initiation coincident with MW2.

The idea behind pulling back the throttle is to ensure you are about to secure the dead engine, but both TQ1&2 seem to have been flopping about

There was some 40 seconds between MW2 and Fuel Shutoff 1. Looks like due time to properly identify, but the identification looks wrong
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Old 6th Feb 2015, 20:55
  #329 (permalink)  
 
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HFACS

Originally Posted by ILS27LEFT
So true: "2 captains and a check pilot = potentially disastrous if something goes wrong"

We are all human beings: to operate efficiently our brain needs no distractions, if we know we are under scrutiny and detailed observation, the pressure and anxiety can interfere with our brain functions to the point that we can make silly basic mistakes which would have not been done if we were not under observational pressure.

Examples: some people do all wrong if they know they are being observed from behind whilst they work on a computer, some people end up doing all wrong if their phone call is being monitored and they know about this, and so on. Many real life examples (driving exams, etc).

We are all human beings. Full concentration is achieved when there is minimal external interference.
During a real emergency it would be better not to be under observation or examination. Anxiety status would certainly not help to get out alive.

This is actually formally recognized in the "Department of Defense Human Factors Analysis and Classification System A mishap investigation and data analysis tool" HFACS http://www.uscg.mil/safety/docs/pdf/hfacs.pdf

OC002 Evaluation/Promotion/Upgrade
Evaluation/Promotion/Upgrade is a factor when an individual perceives that their
performance on a task will inappropriately impact an evaluation, promotion or
opportunity for upgrade and this pressure creates an unsafe situation.
It doesn't even have to be a formal 'check ride' just having the check captain there is sufficient psychological pressure to raise the risk of error.
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Old 6th Feb 2015, 20:57
  #330 (permalink)  
 
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I strongly agree with Lomapaseo at dash 289. If either one fails,autofeathers,and just lets You just know about it,just fly the plane. It has speed,it is climbing,and not much to do for the failed one right now. Later,when alt and situation permits,you may turn your attention to something else. Sure it`s a lightshow with perhaps guiding vocals,-but who would care less. If it flies and climbs,that,s all there is to think about. All the World`s time later on,to think and troubleshoot why it did that.
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Old 6th Feb 2015, 21:01
  #331 (permalink)  
 
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Fully stalled all the way in that video.
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Old 6th Feb 2015, 21:15
  #332 (permalink)  
 
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Fully stalled all the way in that video
...then they are exceptionally lucky to have missed all those buildings...

...and it is truly an exceptional aircraft design that can maintain a ROD of 400-600fpm in a fully developed stall.

I think they were un-stalled and in full control pretty much all the way down that descent, apart from right at endgame.
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Old 6th Feb 2015, 21:21
  #333 (permalink)  
 
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at 57 seconds into the lost in saigon video post, it appears, repeat APPEARS the right prop is feathered or at least not turning...again RIGHT/Starboard/number 2
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Old 6th Feb 2015, 21:29
  #334 (permalink)  
 
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@ Uplinker...

Jets are way easier to fly than Turboprops.
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Old 6th Feb 2015, 21:31
  #335 (permalink)  
 
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At this time we still don't know who the PF and PNF were and what role if any the third pilot may have played.

This could be a crucial part of this crash.
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Old 6th Feb 2015, 21:38
  #336 (permalink)  
 
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#327
The idea behind pulling back the throttle is to ensure you are about to secure the dead engine, but both TQ1&2 seem to have been flopping about
With PT6 engines, in case of suspected engine problems, both power levers stay or go to TOGA [or appropriate] power.

Why would "one" throttle be retarded in an ATR?
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Old 6th Feb 2015, 21:54
  #337 (permalink)  
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Post 301:

After my question about the fuel booster pumps being left switched off.

They are not covered by Takeoff Config Warning, why should they be?
Because they give entirely the symptoms:

Post 327:
The graphs show fluctuating torque readings in both engines. If this apparent state of affairs is validated, one can only imagine the confusion in the cockpit.

FOUR TIMES in two years I picked up on my copilot's failure to switch them on. One of these pilots was an experienced ex RAF pilot that had made a career-altering mistake in leaving them off about a year before. The next incident I won't detail, but it included a Mayday in hilly terrain due to leaving them off.

This entire catastrophe could have been caused by a decision in aviation in general to follow manufacturer's aged logic and not implement changes based on operating experience.
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Old 6th Feb 2015, 23:00
  #338 (permalink)  
 
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Can anyone explain why the TQ is indicated spiking up and down on the FDR when the propellers are feathered? The FDR gives the impression the TQ spikes are quite pronounced but I can't think of why if would do this. I used to fly Dash 8's and Dornier 328's but I don't remember the torque doing his when the prop was feathered (although it was a long time ago so my memory is stretched).

Jets are indeed way easier to fly when it comes to engine problems. I forgot how tricky an unscheduled auto feather could be.
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Old 6th Feb 2015, 23:16
  #339 (permalink)  
 
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I understand some company procedures on turboprop twins mandate the active protection of the functioning engine by the PF as first priority - this is noted in the other thread on this topic in Prune. As stated above if you are in level flight or climbing , it doesn't initially matter what bells are going off, its an incident not yet an accident.
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Old 6th Feb 2015, 23:34
  #340 (permalink)  
 
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Theinquisitor, I don't know where you get your 400 - 600 fpm from In that video the aircraft has a nose up attitude of around 10 degrees, and is descending at an angle of at least 14 degrees (may be more depending on how far away from square on the camera angle is). We know that the groundspeed was around 81 kts, so the verical speed at that point must be around 20 kts or 2000 fpm (81 * tan(14))

I took these angles by putting a protractor on the screen, so may not be that precise, but certainly a lot more than 400 - 600 fpm.

Another way to get the rate of descent is to look at the video in post #8. From when the aircraft first comes past those high rise buildings to the point of impact is 5 seconds. At 600 fpm that would mean a descent of only 50 feet, we can see it is much more than that. Then look at the flight data record so far released and we can see that in the last 5 seconds the rate of descent was greater than 2000 fpm, and that the average rate for the last 12 seconds was 1500 fpm.

What this tells us is that when the aircraft went past that building in the video, its rate of descent was between 1500 fpm and 2000 fpm, and increasing.

On that basis I will stick to my comment that the video segment shows an aircraft that is stalled and not under full control.
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