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Continental TurboProp crash inbound for Buffalo

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Continental TurboProp crash inbound for Buffalo

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Old 15th Feb 2009, 20:22
  #321 (permalink)  
 
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From Yahoo...Does this make sense?

Here's an excerpt...

"According to the flight data recorder, the plane's safety systems warned the pilot that the aircraft was perilously close to losing lift and plummeting from the sky.

Moments before the crash, a "stick shaker" and "stick pusher" mechanism had activated to warn the pilot that the plane was about to lose aerodynamic lift, a condition called a stall. When the "stick pusher" engaged, it would have pointed the nose of the plane toward the ground to try to increase lift.

Indicator lights showed that deicing equipment on the tail, wings and propeller appeared to be working, Chealander said.

Investigators who examined both engines said it appears they were working normally at the time of the crash, too".



Plane that crashed near Buffalo was on autopilot
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Old 15th Feb 2009, 20:23
  #322 (permalink)  
 
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thank you deano...do you know anything about the AD about the asi/pitot/static system in 2007?
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Old 15th Feb 2009, 20:24
  #323 (permalink)  
 
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We need to be careful about speculating about what the crew did wrong or even how the aircraft should have been designed/certificated.

The reason for the discussion is to learn. So let's concentrate on what should be done in various circumstances that might be related to icing on wings and/or tailplane.
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Old 15th Feb 2009, 20:29
  #324 (permalink)  
 
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A possible manual flight scenario. The gear are lowered, then 20 seconds later the flaps are selected to 15. The flaps trigger a genuine tailplane stall. The pilots recognize it and pull the yoke back and raise the flaps (and gear as well). Then the pitch up and flap retract lead to a wing stall. If enough ice existed on the tailplane to cause it to stall, then enough ice might have been on the wing to cause it to stall at a higher speed than expected.

Of course now we know the AP was connected. What if the autopilot reacted to a genuine tailplane stall, which then lead to a wing stall (combining AP responses and pilot responses to retract flaps and gear). Does the Q400 AP have the logic necessary to cope with an icing induced tailplane stall, and the pilot's additional responses? Then perhaps the wing stall triggered the stick shaker/pusher system, which suddenly disconnected the AP on an upset iced airplane at low altitude?

Just how fast can the handling problems add up in such a scenario?
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Old 15th Feb 2009, 20:31
  #325 (permalink)  
 
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Reason that Flybe and other operators use this inferior piece of s**t is COST! Safety is out the back window
Completly irrevelant and childish comment, would like to know how you could back up your argument of saying the Q400 is "
inferior" and implying it is unsafe?


Anyway back to the more 'sensible' posts.......


The Q400 doesnt have autothrotles, and yes there was a problem with the pitots which gave an IAS MISMATCH. This was fixed on all the Dash's (in the UK at least) by upgrading the heaters. However the heaters are now so effective that they burn out quicker and are replaced much more often.
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Old 15th Feb 2009, 20:42
  #326 (permalink)  
 
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flying tin cans

there is some concern that the AD which you mention was not accomplished on this particular plane.

We all have our preferences for airplanes. The planes I respect the most have been retired from my airline. I would not choose the Q400 on my list of top ten airliners.

Is the wing on the Q400 exotically laminar or is it a big thick hershey bar kind of wing? just wondering.
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Old 15th Feb 2009, 20:44
  #327 (permalink)  
 
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PRELIMINARY investigation indicates autopilot was on when the plane crashed but that has not yet been confirmed by FDR.

Indicator lights showed deicing equipment on the tail, wings and prop seemed to be working, and both engines appeared to be 'working normally'.

Flight data showed severe pitching and rolling before impact.

Re the fact plane was facing away from airport: Obv, NTSB are looking at whether it had gone into a flat spin.
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Old 15th Feb 2009, 20:46
  #328 (permalink)  
 
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Totally agree that the DHC 8 is a thoroughly inferior aircraft (built down to cost) for reasons already explained by others.

Flies low and more prone to encounter bad weather and icing conditions.

Has the cheapest anti icing system the manufacturers could get away with. Rubber boots are low tech, inefficient and prone to problems.
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Old 15th Feb 2009, 20:49
  #329 (permalink)  
 
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Anyone like to explain why turboprops like the Q400 dont have hot bleed air deicing?
Not enough hot bleed air to keep the wings and stabilizers warm.
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Old 15th Feb 2009, 20:50
  #330 (permalink)  
 
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inflatable membrane concept

Is it possible to explore the inflatable membrane concept on this site with everyone? I would like to post my thoughts?
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Old 15th Feb 2009, 20:51
  #331 (permalink)  
 
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If they had more powerful engines then there would be bleed air to spare to drive a proper hot air system............

Its all about cost and the fact that this really is an airborne Trabant (I nearly sed SKODA!!)
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Old 15th Feb 2009, 20:52
  #332 (permalink)  
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Clandestino you are completely wrong.

There is plenty of 'spare' hot air from those huge engines. As I said earlier it is for type commonality between the 400 and the 300/200/100's.
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Old 15th Feb 2009, 20:55
  #333 (permalink)  
 
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It is not a pilots personal preference that I have a problem with, I also have my own which will be different to others.

However implying an aircraft is unsafe before an official accident report has been released for the first fatal accident of the type is rash to say the least!


If they had more powerful engines then there would be bleed air to spare to drive a proper hot air system............


Please get some facts before posting....the Q400 is extreemly overpowered, the reason it doesnt have a Hot air de-ice system is to keep a common type rating, not because the lack of hot bleed air
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Old 15th Feb 2009, 20:56
  #334 (permalink)  
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as they are cheaper to run
To me that means efficient. Now have you got any sensible comments?
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Old 15th Feb 2009, 20:57
  #335 (permalink)  
 
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Newest info i just received:
As the airplane slowed for configuration it went well below minimum ref speed with flaps at 5.

IF thats the case we can forget the tail-stall story and it was pilots error wih subsequent "normal" wing stall....
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Old 15th Feb 2009, 21:00
  #336 (permalink)  
 
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The L188 Electra had turboprop engines and hot wings...but they were used as DE ICE systems not ANTI ICE .

BE careful out there...if you get icing...use your equipment to get OUT. Especially in turboprop types.
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Old 15th Feb 2009, 21:01
  #337 (permalink)  
 
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From The BBC, my bold

The Continental Airlines pilot may have breached federal safety recommendations by flying in such conditions, investigator Steve Chealander said.
Pilots are recommended to fly manually in icy weather, he said.
Analysis of the plane's data recorders shows the crew noticed significant ice build-up on its wings before the crash.
"You may be able in a manual mode to sense something sooner than the autopilot can sense it," said Mr Chealander, a spokesman for the National Transportation Safety Board (NTSB).
He told the Associated Press news agency that the NTSB recommended pilots disengage their craft's autopilot facility in icy conditions.
Anyone else know anything about this little gem?
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Old 15th Feb 2009, 21:03
  #338 (permalink)  
 
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Pending what the official investigation has to say I agree with Flight Safety that this scenario looks too much to Tailplane Stall due icing.

I recommend you take a look at this NASA Video about Turboprops Tailplane stall due icing and how this uses to happen when configuring the airplane for landing, specially when lowering the flaps and how difficult the identification and recovery of this sittuation could be Tailplane Icing

Rest in peace!
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Old 15th Feb 2009, 21:07
  #339 (permalink)  
 
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There is plenty of 'spare' hot air from those huge engines.
CFMs? Sure! Especially if the wing leading edge is thinner and inner part is not heated anyway and stabilizers are not heated at all. However there is performance and fuel flow penalty - not much but it has to be accounted for.

PW1xx (yes, even 150) combined with much bigger area to keep warm? Small chance.

And I wholeheartedly agree that every turboprop should be able to cruise fast and above the weather and wonder why everyone is not getting rid of their ATRs and DHCs and buying Tu-114
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Old 15th Feb 2009, 21:15
  #340 (permalink)  
 
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Jackdaw

Please keep my quotes in context.

It was a reply to a post which said the Q400 did not have boots because it was underpowered.

I completly agree saftey is aviations no.1 priority, but I have yet to see a report saying the boots on a Q400 are unsafe
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