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-   -   TransAsia in the water? (https://www.pprune.org/rumours-news/555876-transasia-water.html)

mad_jock 4th Feb 2015 10:21

A better term would be reduce angle of attack which as we all know doesn't necessarily mean select a nose down attitude compared to the horizon.

Jet Jockey A4 4th Feb 2015 10:22

@ Vilters...
 

Procedures may vary, but at first sign of an engine failure it is nose down.
That would depend at which stage of flight you are in.


And yes the Boeing/Airbus video on stalls is very informative but that relates to "big" under the wing jet powered aircrafts and may not necessarily apply for a turboprop type aircraft.

Although speculative at this time on my part and as others have also speculated, it could be that a VMCA incident occurred.

Time will tell when the "black boxes" are read.

Livesinafield 4th Feb 2015 10:28

Interesting thanks, but in all my OPC's LPC etc i have never been taught to lower the nose, I am more interested in my speed

Only time i would consider lowering the nose is if i was at a very high pitch angle and even then i am going to keep some of that while i slow towards V2, if i simply lower the nose as you say and its low level i suspect we will loose height

I guess it all varies what type your flying...

Massey1Bravo 4th Feb 2015 10:35


What is more likely is poor handling technique on the initial flame out leading to overuse with ailerons to maintain directional control
Interesting, I didn't expect the overuse of ailerons would have such a major impact on performance to the point where the aircraft cannot maintain altitude, especially for a large turboprop. I mean this isn't a MU-2 with roll spoilers.

stuckgear 4th Feb 2015 10:55

https://pbs.twimg.com/media/B8_LBvpIYAAEr9U.jpg

Loose rivets 4th Feb 2015 10:55


"At the press conference, it was also revealed that the turboprop previously had a faulty left engine which was replaced in Macau.
Oh dear. I suppose there's just a chance the 'fault' was upstream of the actual engine.


BO0M, Is there an improved check or automation for those fuel pump switches above the skipper's head? In my time on type I couldn't believe how many times the NFP failed to set them. I heard of at least two times it lead to a Mayday being put out.

(as an aside, I couldn't believe it wasn't part of the engine fire drill to turn them off. Just one example of FCOM overruling experience.)

mad_jock 4th Feb 2015 10:58

Don't think most on here realise the amount of drag you get on a prop if you don't secure it.

To simulate a feathered prop its not uncommon to have to use 10-14% on the dead engine.

Over the years there have been many many incidents when there has been a partial failure and the engine keeps turning but giving intermittent burst of power or something below the simulated failed engine torque.

On my TP type at MTOW the stall speed is 84 knts. Vmca is 101knts Vr is 111knts.

Tim Allen at BAe systems did a extremely good article about the dangers of trying to nurse an engine home on a turbo prop when it is producing less than 15%- 20% torque 10 years ago. And its something that I have hammered into me in the sim as well.

Vmca goes through the roof with one engine at full chat and the other at flight idle way way above Stall speed. There are no numbers produced but in the sim my type will run out of rudder and aileron at 115-120knts and the stall speed is still the same and it won't climb never mind pref A performance until the engine is secured.

Greenlights 4th Feb 2015 10:58


What is more likely is poor handling technique on the initial flame out leading to overuse with ailerons to maintain directional control
indeed.
so, wondering pilot's experience, how is the recruitment in this airline, the training etc

biscuit74 4th Feb 2015 10:59

This recent series of posts does raise a query in my mind.

The quite high deck angles achieved on initial climb out insome aircraft today suggests that on occasion a significant reduction in angleof attack or easing of pitch angle, done reasonably smartly, may be helpful toensure the aircraft remains above Vmca following a partial or subtle power loss. It will take some time for any lost airspeed torecover in a heavy aircraft – is that demonstrated in simulator exercises?Especially recalling that many pilots may find controlled flight at or very near Vmca ‘challenging’in some types.


I recall in UK gliding, after a series of nasty accidents a few years ago, a lotof effort was spent reminding pilots that just getting the nose down wasn’tenough. It is important of course to wait until there is sign of positive rise in airspeed beforemanoeuvring vigorously.

That short video clip also seems to me to show the effect of insufficient airspeed, for whatever reason at that point. Horrible to see, horrible to feel an aircraft dropping away from you. Impressed anyone survived.

FullWings 4th Feb 2015 11:02

It does have all the hallmarks of a Vmca departure, maybe combined with a wing drop. High pitch attitude, RoD building then a final rapid roll into the water. What malfunction(s) and/or handling might have led to that we have yet to see.

I remember what my first flying instructor told me, which was: “If you’re going to crash, crash with the wings level”, i.e. if possible, keep the aircraft under control, even if you’re going down to a certain impact. Fortunately, I’ve never had to put his advice into practice...


Interesting thanks, but in all my OPC's LPC etc i have never been taught to lower the nose, I am more interested in my speed
Until we started doing LOEs as part of our ATQP, OPC/LPC (or even IRR, back in the day) engine failures consisted of V1 cuts because they we supposed to be the most critical or difficult. We all know that’s not the case and a failure just as you’re reached the AEO attitude needs a swift reduction in pitch otherwise you’ll be going back past V2 on the way to Vmca. Waiting for speed trends to develop could leave you in a less than desirable situation.

Same could be said for a power loss in a turn or during clean up.

Golf_Seirra 4th Feb 2015 11:02

Considering they would have been not far off Accel Alt, may well have been a case of securing the incorrect engine and left with no options. I agree that they seemed to be trying to lift the nose to make the river in front of them. Pity some companies think operating turbo-props are for beginners although both crew had above average hours...oh dear, we seem to be hour measuring again...

funfly 4th Feb 2015 11:06

keep the wings level?
With due respect, the aircraft missed high rise buildings and a busy road, would it be so difficult as to think that the pilot acted in order to achieve this at the expense of his aircraft and obviously his own life?

Volume 4th Feb 2015 11:09


Interesting thanks, but in all my OPC's LPC etc i have never been taught to lower the nose, I am more interested in my speed
Well, if you look at your nose, it indicates where your speed will be in the near future... Additionally, at the time you lose an engine (or loose thrust) your flight path angle immediately gets shallower. If you keep the nose at the same pitch, your AoA will increase meaning your speed will decrease. If you lose an engine, you have to lower your nose to maintain AoA. Naturally an aircraft will do that by itself, but if you want to be a little proactive to prevent a drop in speed, you better use the elevator to expedite the natural reaction.

I guess it all varies what type your flying...
Depending on the effect thrust has on the pitching moment, aircraft will drop the nose immediately if you lose thrust (even more than necessary), so yes it all varies with type what you have to do, however the nose has to get lower, whether you do that or it happens naturally is not that important.

rnzoli 4th Feb 2015 11:10

Were these recordings listened to by anyone? Was there a Mayday call?
Airport Detail: TSA | LiveATC.net

Cusco 4th Feb 2015 11:23


Were these recordings listened to by anyone? Was there a Mayday call?
Airport Detail: TSA | LiveATC.net
See post #10

Mayday at 23.28 or thereabouts

Huck 4th Feb 2015 11:25

Looking at the last video - there is no way either motor was producing torque. No way. 2700 hp per side...... A Vmca roll would come after a significant climb rate.....

aa777888 4th Feb 2015 11:29

Perhaps the wrong engine was secured?

wooski 4th Feb 2015 11:36

maybe autofeather didn't work, or manually feathered/shut wrong engine...

doing a search seems there was a discussion in the tech log about the procedures , not sure if its the same model

http://www.pprune.org/tech-log/44625...-take-off.html



Huck Looking at the last video - there is no way either motor was producing torque. No way. 2700 hp per side...... A Vmca roll would come after a significant climb rate.....

Bokkenrijder 4th Feb 2015 11:37


Perhaps the wrong engine was secured?
Or kicked the wrong rudder?

beamender99 4th Feb 2015 11:44

Now lifting some of the wreckage.

https://www.youtube.com/watch?v=T8GmxMGCDh4


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