Stormy Knight (and others)

That aircraft was out of control well before the wires. They'd lost directional control before they crossed those buildings.

This accident looks to have "loss of control at Vmca written all over it.

No, can be up to 74

It doesn't look to me that it touched the buildings.
It went under the high voltage wires.
Perhaps the final straw was trying to pull-up to miss those wires...

Jack - normal config is 72 pax seats for this carrier

Yes we are on the same street, if you go thru the crossbar the lightpost on the right is one removed. There is a white blob of paint to the left of the base of it.

Also here's another view looking up from the ground showing the proximty of the overhead power lines...crossing near that crossbar.

https://www.google.com.au/maps/@25.0...ve2w!2e0?hl=en

Looks to me like left Engine failed but didn't feather, crew let it get too slow and went below VMCA.....all over red rover.....

From a Reuters report:

and left is afaik critical engine in ATR

A question for an ATR pilot.

Let us assume that, for what ever reason, there was a loss of power on left engine, what kind of performance is possible assuming the auto feather is successful?

If the auto feather malfunctions, and therefore a windmilling prop condition exists, the performance is significantly degraded until manual intervention occurs in a timely manner.
This will be practiced during LPC/OPC in the simulator. How much more difficult is it to control and survive?

Loss of airspeed is always the final critical factor in this type of accident.

Remember the accident with the Airtours crew being flown GLA-ABZ in a Cessna twin?. This of course was not a performance A machine

I've got 10 years on type and currently a TRE/TRI on the 600 for the last 2 years.

The ATR is perfectly capable of maintaining a rate of climb with an unfeathered prop if controlled correctly. ATR don't specifically have a procedure to deal with the no autofeather scenario due to the odds of it occurring. That been said many operators have their own for safety reasons.

Generally a crew would identify the ATPCS had failed during the initial memo items immediately after the gear is selected up (let's say 100ft). Timely identification takes place and the engine would be shut down. This is not a difficult procedure and an experienced crew would have no issues maintaining 200/300ft/min until completed

I personally don't like speculating on accidents but I highly doubt a failure of the auto feather system is the culpriate. If indeed there was a failure of the left engine after takeoff then it could be as simple as the crew mishandling the failure.

One more video:

https://www.facebook.com/video.php?v=1053519784674205

They were going to crash well before that wing drop/Vmca roll at the very last few seconds. IMO it was probably a secondary/wing drop stall, possibly the pilots pulled just a bit too much after they realised they might hit the motorway.

High sink rate + pitch relatively high +wings level = partially/fully stalled

Given that the ATRs should have enough performance to not fall like a rock after an OEI scenario with wings level (with or without autofeather) this is leading me to believe it's a double engine failure and I agree with pattern_is_full that the pilots might be trying to pull off a 'Sullenberger' on the river.

Wing drop at stall.
 

What you see is not roll command. That is a typical wing drop at a stall with a failed engine.

Take off, loosing the left engine, getting too slow, stall, and wing drop.

The wing drop is agravated because of the engine flame out. You loose the prop wash generating extra lift on the left wing, so the left wing WILL stall before the right wing.

Procedures may vary, but at first sign of an engine failure it is nose down.

Then fly airspeed, airspeed, airspeed, airspeed.
Speed is your life.
Even if you have limited altitude, and you have to sacrifice altitude for speed. SPEED is your life .

Regarding the video in post 22:

To me it looks like both propellers are not spinning very fast. Maybe a double flame out? Trying to stretch the glide, they saw the brigde coming up and stalled (the left wing) trying to miss it? It doesn't make sense that experienced pilots would mess up a single engine flame out.

Then again, a double flameout would probably feather both props?

EFAT, full of fuel...lucky to be in the water....and shallow water at that.

A double engine flame out is highly unlikely as is the no auto feather scenario.

What is more likely is poor handling technique on the initial flame out leading to overuse with ailerons to maintain directional control, this is all due to an over realiance on the "new" auto rudder trim.

Seen it many times in the sim and when that rudder snaps out its not pretty.

All that said these comments are in no way saying that's what has occurred I'm not here to point fingers or do the I know why game. It's a very sad accident for all involved.

I don't think it was stalled.

I also don't think the LH engine was secured.

Maybe it was still giving some power but not as much as to be equiv to feathered. Auto feather didn't kick in because they didn't get neg torque and they didn't realise that getting 5-10% torque is worse than feathered.

I think they lifted the nose because they thought they were going to hit those flats.

Speed came back and went below Vmca and then they ran out of roll/yaw authority.

what?! we are flying Perf A turboprops here not PA28's.......

It comes from a dashboard cam, most likely the frame ratio wouldn't cope. Thus the "slow-mo" effect.

I hadn't see the video yet with the woman in the car. Yes now it's more clear with the wider angle. If they didn't hit the buildings it looks they came very, very, close.


Lucky people on the ground indeed

"The Civil Aeronautics Administration said the aircraft involved in Wednesday’s disaster had just completed a safety review on January 26. The pilot had 4,914 hours on his record and his co-pilot 6,922 hours, the authorities said."

There are about 15 survivors according to 23 believed dead, 20 missing in TransAsia crash in Taipei - Taiwan News Online

Edit: According to the CAA there was also a third pilot in the jump seat with over 16,000 flight hours of experience, says FlightGlobal: http://www.flightglobal.com/news/art...atr-72-408669/

Furthermore, FlightGlobal notes that the airline said: "At the press conference, it was also revealed that the turboprop previously had a faulty left engine which was replaced in Macau. The ATR 72 was powered by Pratt & Whitney PW100-127M engines." http://www.flightglobal.com/news/art...ke-off-408675/

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.

@ Vilters...
 

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.

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...

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.

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.)

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.

indeed.
so, wondering pilot's experience, how is the recruitment in this airline, the training etc

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.

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...

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.

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...

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?

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.
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.

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

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.....

Perhaps the wrong engine was secured?

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

Or kicked the wrong rudder?

Now lifting some of the wreckage.

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