Taiwan Transasia crash and asymmetric thrust

FloridaPilot

FloridaPilot

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There is a source out that says the pilot shut off the working engine before the crash:

http://www.msn.com/en-us/news/world...ff-working-engine-source/ar-AAcoWp5?ocid=iehp

People are saying it was a dumb thing to do but in some rare cases turning off the working engine or at least lowering the power helps when it comes to asymmetric thrust? Can a twin in this case with the payload that it had still fly on one engine?

If you cannot depend on the airplane to fly with one engine why have a twin in the first place?
 
FloridaPilot said:
There is a source out that says the pilot shut off the working engine before the crash:

http://www.msn.com/en-us/news/world...ff-working-engine-source/ar-AAcoWp5?ocid=iehp

People are saying it was a dumb thing to do but in some rare cases turning off the working engine or at least lowering the power helps when it comes to asymmetric thrust? Can a twin in this case with the payload that it had still fly on one engine?

If you cannot depend on the airplane to fly with one engine why have a twin in the first place?
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Unlike a general aviation twin, Transport Category airplanes are required to have positive single engine climb performance on takeoff assuming the failed engine propeller is feathered.

In this case (and the information was actually already released early on in the investigation) one of the pilots pulled the fuel shutoff lever for the operating engine in the process of dealing with the failed engine.

It was an incredibly dumb thing to do. Even if you are below Vmc (minimum controllable airspeed on a single engine), you would never shut off the good engine. Simply pulling the throttle back and reducing power will prevent the loss of control.
 
in that type of aircraft, unless the autofeather system fails, the only thing to do until acceleration altitude is fly bug speed and put in rudder. the speed bugs are set to to maintain proper airspeed for single engine initial climb and the autofeather system will feather the prop on the bad side. just center the ball and wait until acceleration altitude. the biggest problem that people coming from light twins have is they are in a hurry to shut it down, and forget they have someone sitting next to them. those people died do to poor piloting and poor training.
 
all the transport category I've worked on have a rudder bias system that puts in rudder or assists for you in the event of an engine failure. Then there is automated thrust increase on the good engine to continue the climb out there too.
 
the atr does not have a rudder bias system but the atcps system does provide 1.8% up trim to the good engine
 
It's not as clear cut as in a piston twin with these. Dead leg, dead engine doesn't always work here. They have autofeather, NTS, overspeed prop, compressor stalls, flameouts etc and multiple other scenarios where it can be hard to tell what exactly is going on. Only way to be sure, is to look at the ball. There can be no engine out or asymmetrical thrust reduction without yaw.
 
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I agree about looking at the engine gauges but this is negative transfer from what most people learned in trainer piston twins. You were taught not to look at the gauges because the manifold pressure gauge could be deceiving, going to ambient pressure when the engine fails. People were taught dead foot dead engine but that doesn't work too well in airplanes with some kind of automatic rudder assist.
 
Everskyward said:
I agree about looking at the engine gauges but this is negative transfer from what most people learned in trainer piston twins. You were taught not to look at the gauges because the manifold pressure gauge could be deceiving, going to ambient pressure when the engine fails. People were taught dead foot dead engine but that doesn't work too well in airplanes with some kind of automatic rudder assist.
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Are we talking about small GA Light twins or transport category twin turboprops?
 
RotorAndWing said:
Are we talking about small GA Light twins or transport category twin turboprops?
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I was talking about the negative transfer which occurs when going from light piston twins to transport category turboprops.
 
RotorAndWing said:
Guess I never experienced that negative transfer or ever dealt with anyone who has.
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Now you know one. When i went to King Air initial they clearly pointed out that I should look at the gauges rather than rely on dead foot dead engine for the reason I stated. I'm guessing they pointed this out because it's probably pretty common for the King Air to be your first turboprop after flying small piston twins and the instructors know this.
 
RotorAndWing said:
Nope, you can look at your engine gauges or indications.
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Perhaps, perhaps not. But in the time you have at hand to make a split decision, the ball will be quicker. There might not be any quick deduction to be had with some of the below scenarios. Stolen from someone else:

- Engine failed, autofeather worked
- Engine failed, autofeather failed (oh, crap)
- Propeller overspeed (oh, crap) (the engine is still operating, and indications will reveal that, but the prop went flat, and you have drag that feels potentially worse than the engine failing)
- Inadvertent propeller feather (the engine is still operating, but the autofeather system decided to go for it). Similar feeling to #1 above
- Electronic engine control failed (engine still operating, but with some degree of power loss... may or may not feather).
 
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stratobee said:
Perhaps, perhaps not. But in the time you have at hand to make a split decision, the ball will be quicker. There might not be any quick deduction to be had with some of the below scenarios. Stolen from someone else:

- Engine failed, autofeather worked
- Engine failed, autofeather failed (oh, crap)
- Propeller overspeed (oh, crap) (the engine is still operating, and indications will reveal that, but the prop went flat, and you have drag that feels potentially worse than the engine failing)
- Inadvertent propeller feather (the engine is still operating, but the autofeather system decided to go for it). Similar feeling to #1 above
- Electronic engine control failed (engine still operating, but with some degree of power loss... may or may not feather).
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Ok, once again, we are talking about transport category turbo props here. There is no "split second decision". It's "identify, verify, perform".

Trying to see how fast you can do this usually ends badly.


-Engine failed, autofeather worked. No problem


- Engine failed, autofeather failed (oh, crap). Verify engine indications

- Propeller overspeed (oh, crap) (the engine is still operating, and indications will reveal that, but the prop went flat, and you have drag that feels potentially worse than the engine failing). Verified with Prop RPM Indication


- Inadvertent propeller feather (the engine is still operating, but the autofeather system decided to go for it). Similar feeling to #1 above. Verified with Prop RPM Indication

- Electronic engine control failed (engine still operating, but with some degree of power loss... may or may not feather). verified with engine indications

:dunno:
 
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A king air is just a light twin with turboprops. We are talking about transport catagory aircraft flow by two pilots. There is somebody to verify what the pilot is dealing with. There is no rush to shutdown an engine. There is only one time in an atr where a quick action is required, a over speed governor failure. In that case the fmu will cause a large surge. Reducing power must be done quickly, but a quick shutdown is not required.

Emergency procedures are a totally differnt concept in a crew situation. Fast is almost always the worst idea. On my current aircraft there is no memory item for engine fire or failure. The response is run the checklist.
 
Is the engine response different from a light twin to a twin turboprop. Does the turboprop engine take it's time to spool like a turbine?
 
My friend who has been with flight safety for twenty years stated not long ago. " you'd be amazed at how bad some pilots are that come thru here, especially from foreign country's. Really poorly trained" Unquote. A classic example would be the Colgan crash near buffalo. A tragic, needless accident. Again, clutch city.
 
FloridaPilot said:
Is the engine response different from a light twin to a twin turboprop. Does the turboprop engine take it's time to spool like a turbine?
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There is a little lag but it is not like a turbo jet. Even at idle the core rpm is still quite high.
 
unsafervguy said:
A king air is just a light twin with turboprops. We are talking about transport catagory aircraft flow by two pilots. There is somebody to verify what the pilot is dealing with. There is no rush to shutdown an engine. There is only one time in an atr where a quick action is required, a over speed governor failure. In that case the fmu will cause a large surge. Reducing power must be done quickly, but a quick shutdown is not required.

Emergency procedures are a totally differnt concept in a crew situation. Fast is almost always the worst idea. On my current aircraft there is no memory item for engine fire or failure. The response is run the checklist.
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When I referred to the King Air I was mostly referring to the instrumentation for the engines (torque instead of MP) and the presence of rudder bias (or whatever they called it, don't quite remember). You didn't need to be that quick even as a single pilot. You only needed to see that the autofeather worked.
 
My comment was more directed at the fact that the king air was designed as a single pilot aircraft. Transports are designed with two crew in mind. Layouts and procedures are set up with that in mind
 
FloridaPilot said:
but in some rare cases turning off the working engine or at least lowering the power helps when it comes to asymmetric thrust?
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if your below VMCG on the ground ( then its an abort)
below VMCA in the air (your poor airmanship has gotten you here in a transport category airplane) but in a light twin yes you are trained to get off the power momentarily to regain control and get your ass above VMCA
 
Everskyward said:
I agree about looking at the engine gauges but this is negative transfer from what most people learned in trainer piston twins. You were taught not to look at the gauges because the manifold pressure gauge could be deceiving, going to ambient pressure when the engine fails. People were taught dead foot dead engine but that doesn't work too well in airplanes with some kind of automatic rudder assist.
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you will still have a really uncoordinated airplane even with the assist ...step on the "ball" or equivalent until the wings are level...works in a baron or a jet
 
taters said:
you will still have a really uncoordinated airplane even with the assist ...step on the "ball" or equivalent until the wings are level...works in a baron or a jet
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But sometimes it can fool you because it will kick in more than necessary. You still need to center the ball yourself but the rudder you are physically using may be the opposite of what you would use with no assist.

Actually a Hawker 800 they demonstrate a V1 cut and tell you to put your feet on the floor without touching the rudder and it does OK. Other airplanes are different but can be deceiving if you just rely on dead foot dead engine.
 
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Everskyward said:
I was talking about the negative transfer which occurs when going from light piston twins to transport category turboprops.
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Probably has more to do with the fact that a pilot working on his initial multi rating in a Dutchess is taught some things in a simplified manner, and the simplification is inappropriate for a lot of larger airplanes.

I say we require 1500 hours, a 30-hour class with 15 hours of sim time in a non-representative airplane before we allow simeone to take the written (as yet to be developed) for a multi engine rating on a private or commercial certificate!:idea:
 
MauleSkinner said:
Probably has more to do with the fact that a pilot working on his initial multi rating in a Dutchess is taught some things in a simplified manner, and the simplification is inappropriate for a lot of larger airplanes.
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There are a number of things which are taught differently in smaller piston airplanes because they are... different airplanes. I was only pointing out that the law of primacy can sometimes get in the way, not that things should be taught differently. You should learn what it appropriate for the airplane you are flying but be prepared to adapt if you go on to other airplanes.
 
Everskyward said:
There are a number of things which are taught differently in smaller piston airplanes because they are... different airplanes. I was only pointing out that the law of primacy can sometimes get in the way, not that things should be taught differently. You should learn what it appropriate for the airplane you are flying but be prepared to adapt if you go on to other airplanes.
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Was "dead foot, dead engine" taught as one of the techniques available, depending upon the equipment you're flying, or was it taught as the only valid technique? Most people seem to be taught the latter, which is an inappropriate simplification, IMO.
 
MauleSkinner said:
Was "dead foot, dead engine" taught as one of the techniques available, depending upon the equipment you're flying, or was it taught as the only valid technique? Most people seem to be taught the latter, which is an inappropriate simplification, IMO.
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That was a long time ago when I got my ME rating (maybe 25 years) so I don't really remember. All I remember is the instructor at King Air school pointing out that I shouldn't use it in the King Air. That was also a long time ago (15 years) but at least I remember that part. It wasn't that I was having problems, but I think it was something that he pointed out to everyone who was coming from airplanes with no rudder assist because he had seen problems in the past.
 
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