ATR-72 Down in Taipei

[Tim Hancock]

At the start of the video you can clearly see that they hit a building and lost part of their left horizontal stabilizer.

[gordner]

Originally Posted by 911_Dude

Not a stall. The pilot was radioing that he had a flame out on one engine. At takeoff power with an engine failure you must add a lot of rudder to keep the plane level with all the asymetric thrust. It is completely within the capability of the aircraft to safely loose an engine on take off. Unfortunatly it was beyond the capability of these two pilots. Pretty lame. US airline pilots practice this stuff every year. It should be second nature, although it is challenging. They just let it get away from them.

It looks to me like the Prop on the failed engine did not feather, if that is the case the pilots did well if anyone walked away....
All speculation until they have a look at what is left.

[DonDavis]

Here's another clip of the same footage with the aircraft in view while still mostly level, but nose up during it's descent.

Tim, I can't see where it strikes a building because when it initially rolls left, the left horizontal stabilizer looks intact. As they cross the freeway, maybe the left horizontal stabilizer struck a light pole? But at that point it was doomed anyway.

[vash]

holy krapp

i just flew out of that airport!! i know that section of highway..damn.

[vash]

they want close that airport. this will fuel that movement.

[spuggy]

Originally Posted by DonDavis

I can't see where it strikes a building because when it initially rolls left, the left horizontal stabilizer looks intact.

First video in the thread (the fuzzy one with the graphics all over it). As the aircraft comes into frame, it's fairly nose-up and pretty horizontal. There looks to be a tail strike on the building, the nose pitches down and it starts to roll. The clearer videos all seem to be cropped.

[edit] it's at about 45 degrees as it comes into frame. Which is a lot closer to horizontal than it is later. As it gets closer to the freeway, you can clearly see half the left stabilizer missing - although in some of the frames before that it looks like it's gone altogether - probably just lighting/lack of contrast.

[Tim Hancock]

Yep... In the video I watched, I clearly saw a tail strike on the building which appears to have shortened the left hor stab a bit. Watch for the puff of debris as it passes the building at the start of the video.

[DonDavis]

The ATR-72 has a T-Tail and I think the view angle during the roll gives the impression that part of it is missing. And it's all the same footage, from the same source. The last link I added has the most complete, uncluttered footage.
Still unsure about building impact.

T-tail...

[pavulon]

Originally Posted by 911_Dude

Not a stall. The pilot was radioing that he had a flame out on one engine. At takeoff power with an engine failure you must add a lot of rudder to keep the plane level with all the asymetric thrust. It is completely within the capability of the aircraft to safely loose an engine on take off. Unfortunatly it was beyond the capability of these two pilots. Pretty lame. US airline pilots practice this stuff every year. It should be second nature, although it is challenging. They just let it get away from them.

If not a stall, please elaborate as to how it came out of the sky. Is it almost entirely an issue with roll (lift force less than gravity force) in this situation?? Have never flown multi-engine so I don't fully understand.

[911_Dude]

Interesting. The tail looks intact to me, especialy as you see it just after dinging the van. Remember its a T-tail. Part of its is hidden from view until its rolled way over.

[911_Dude]

Originally Posted by pavulon

If not a stall, please elaborate as to how it came out of the sky. Is it almost entirely an issue with roll (lift force less than gravity force) in this situation?? Have never flown multi-engine so I don't fully understand.

In an engine out situation, if you give up on the rudder or dont put enough in in the first place you get a huge amount of roll from the wing with the good engine going forward from (in this case) left yaw. As soon as you loose an engine one must immeadiatly counter the yaw with a lot of rudder and lower the nose a bit.

Im just arm chair QBing tho. Looks like he cleared the buildings almost level. We dont know when he lost the left engine. If it happened just before he comes into view, then the flight path is a classic case of dead engine, take-off thrust, low airspeed, and no corrective action with rudder-flight controls. I see current airline pilots do this in the sim more than you would like to know.

If he stalled, it would be very nose down. That never really happends. Just a lot of roll. Just my .02



.

[ckelly78z]

I didn't see the actual building strike or the puff of smoke at that instant, but I did see the whole plane shudder and immediately roll left and descend towards the highway. Just the instant after hitting the taxicab with the end of the wing, you can see that the left rear stabilizer looks a bit chopped off.

[widebody911]

Originally Posted by petrolhead611

I saw theairspeed /altitude chart on another forum; dont think he ran out of airspeed(109knots just before impact) but he sure ran out of altitude.

You usually run out of airspeed immediately after you run out of altitude...

[Hawkeye's-911T]

It looks to me like the Prop on the failed engine did not feather

Some pundits are saying the failed port engine did not "auto-feather" therefore was a major contributing factor to the accident.

[Baz]

Wonder if the left prop feathered when the engine went out.

[rick-l]

Originally Posted by widebody911

You usually run out of airspeed immediately after you run out of altitude...

You're supposed to run out of altitude airspeed and ideas all at the same time.

[t6dpilot]

Look at the whole video. You can see how it appears the pilot was probably trying to maintain a glide path that got them over the elevated highway and into the river. Going down in the elevated highway area would probably have resulted in everyone perishing. When they lost the left engine and the prop didn't feather, it was going down fast. Trying to maintain a glide path that got them over the highway most likely caused the airspeed to fall below blueline. That is the safe single engine airspeed above which you will not torque roll due to asymmetric thrust. With a windmilling flat pitch propellor on the dead engine, the BL airspeed might even be higher. There is some margin built in, but he probably got slow enough the the running engine pulled the right wing over the dead engine.

Sad to see and am glad there are some survivors.

[FLYGEEZER]

Some of the "still" videos I've seen, looked to me like the left engine had auto feathered or was in process of feathering.....lotsa blade angle . I'm thinkin' the captain was trying to put it in the river & turned into a dead engine at a very low airspeed. The rudder then became an elevator after the left wing stalled. Sad.

[flipper35]

Originally Posted by spuggy

First video in the thread (the fuzzy one with the graphics all over it). As the aircraft comes into frame, it's fairly nose-up and pretty horizontal. There looks to be a tail strike on the building, the nose pitches down and it starts to roll. The clearer videos all seem to be cropped.

[edit] it's at about 45 degrees as it comes into frame. Which is a lot closer to horizontal than it is later. As it gets closer to the freeway, you can clearly see half the left stabilizer missing - although in some of the frames before that it looks like it's gone altogether - probably just lighting/lack of contrast.

Help me out here, I am not seeing any evidence of damage on the tail anywhere in these pictures or in the video.

[Noah930]

Originally Posted by flipper35

Help me out here, I am not seeing any evidence of damage on the tail anywhere in these pictures or in the video.

Go forward a few more frames...