ATR 72 A Death Trap??

[PR3D4TOR]

It's still full of assumptions. Most critically about the mass of various components.

[DaveBB]

Most critically you asked for evidence of the vertical stabilizer being too small, and I provided it.  Now you are attempting to discredit the source.  Nice try.  Maybe you'll win next time.

[DaveBB]

http://www.fzt.haw-hamburg.de/pers/Scholz/arbeiten/TextNita.pdf     Please reference page 120 for the size of the vertical stabilizer as supported by modern aeronautical formulas.

[PR3D4TOR]

Ok, on another bbs they came up with the following:

Vmca Flap 15 1000 ft 25°c  93 kts

Vstall Flap 15 a 22000 kg 100 kts

Vstall Flap 15 a 18000 kg 91 kts


So when heavy (take-off) the ATR's stall speed is faster than its control speed in a one-engine configuration. The plane would stall before the rudder becomes ineffective.

[PR3D4TOR]

Here's the Quick Reference Handbook for the ATR 72-500.

It has the flame-out emergency procedure and how to determine Vmca.



http://www.scribd.com/doc/141616443/ATR-72-500-QRH#scribd

[Zimme83]

The ATR, just like all other twin engine props, are certified to fly on one engine. Even if its fails at V1. But even so there are a buttload of twins that have crashed beacuse the pilot fails to fly the plane on one engine. Its irrelevant that it was an ATR, could have been a king air, dash 8, saab 2000 or any other twin on the market.

[Puma44]

The ATR, just like all other twin engine props, are certified to fly on one engine. Even if its fails at V1. But even so there are a buttload of twins that have crashed beacuse the pilot fails to fly the plane on one engine. Its irrelevant that it was an ATR, could have been a king air, dash 8, saab 2000 or any other twin on the market.

Spot on!  Well said. 

[Wmaker]

http://www.fzt.haw-hamburg.de/pers/Scholz/paper/RRDPAE-2008-Presentation_ATR72.pdf

From what I gather, this is a research paper showing that the ATR 72 should have a 12.5% larger vertical stabilizer.

Engineer student vs. a team of designers.

Anyway, I still haven't heard about an accident that is directly related to insufficient yaw control.

Personally, when I was a kid, I commuted many times in an ATR-72....still a live here.

[earl1937]

Ok, on another bbs they came up with the following:

Vmca Flap 15 1000 ft 25°c  93 kts

Vstall Flap 15 a 22000 kg 100 kts

Vstall Flap 15 a 18000 kg 91 kts


So when heavy (take-off) the ATR's stall speed is faster than its control speed in a one-engine configuration. The plane would stall before the rudder becomes ineffective.

Sorry, but your reply makes no sense! If the stall speed is higher than the single engine VMC, why even have a pubished VMC at different weights? I think you have misunderstood something about that post.
They could up with a VMC via the old slide rule method back in the day, but now do it with a computer! Then the test pilots have to go out and verify if that is in fact a accurate statement. That is all done in the design and development stage.

[PR3D4TOR]

Earl I posted a link to the ATR's quick reference handbook. All is there.

Now stop calling people idiots and blaming them for something they are completely innocent of.

[FTJR]

It would seem that the pilots didn't identify/confirm the correct engine to shut down. I cant speak for that airline, but my current employer and the others I have worked for in the last 15 years train us to be very careful in identifying the engine to shut down.  The pilot who is doing the actions puts his finger on the control to be moved(pushed/selected) and asks the the other pilot to confirm before it is actioned.  While I have nothing to hand, I think this come to pass after many previous examples of people rushing to shut down the engine and getting the wrong one. I can understand in a situation which you only experience in training, a real life event would be scary and repetitive training would likely be the only thing to save you.

Its no the aeroplane, its not really the pilots, its the training thats failed.

[artik]

Good article about the incident: http://www.flightglobal.com/news/articles/transasia-ge235-shutting-down-the-wrong-engine-408790/

It isn't yet clear what happened and why pilots had shut-down the wrong engine but... it is sad, mostly because it was likely preventable.

[colmbo]

Sorry, but your reply makes no sense! If the stall speed is higher than the single engine VMC, why even have a pubished VMC at different weights? I think you have misunderstood something about that post.
They could up with a VMC via the old slide rule method back in the day, but now do it with a computer! Then the test pilots have to go out and verify if that is in fact a accurate statement. That is all done in the design and development stage.

The old Islander had a Vmc that was below stall speed as well.

[715]

May I ask a couple of uninformed dumb questions? 

Why do you shut down an engine that has failed?  To prevent eventual fires?  Wouldn't flying the plane be more important?

Why isn't the little warning light of a failed engine right on the control you use to shut down the engine (throttle?) so there is no confusion?

[colmbo]

May I ask a couple of uninformed dumb questions? 

Why do you shut down an engine that has failed?  To prevent eventual fires?  Wouldn't flying the plane be more important?

Why isn't the little warning light of a failed engine right on the control you use to shut down the engine (throttle?) so there is no confusion?

It's not that you shut the engine off, although in some cases it is important to get it stopped quickly.  The most important thing is getting the propellor feathered.  A windmilling propellor results in a tremendous amount of drag -- so much that in many cases the aircraft will not be able to maintain altitude.  Once the prop is stopped then you continue with "securing" the failed engine by doing things such as shutting off fuel feed, turning ignition/magneto switches off, closing cowl flaps, etc.