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Continental TurboProp crash inbound for Buffalo

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Continental TurboProp crash inbound for Buffalo

Old 15th Feb 2009, 05:06
  #241 (permalink)  
 
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Lightning6 --

In ref to co-pilot's final voice characteristics:

Can't guess, but we had a situation here in Northeastern Pennsylvania and I was given the final thirty seconds of the tape, which included what I thought was a significant change in the pilot's voice.

"What I thought" are the operative words. My newspaper did not publish this information for those reasons. I did not know what was going on in the cockpit that would have affected the pilot's voice.

In this case, it's much better to dump what could be very erroneous information than to let Faux News definitively state something very wrong. We (journos) weren't there and it's all quite subjective.
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Old 15th Feb 2009, 06:08
  #242 (permalink)  
 
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thank you to Mansfield for first hand knowledge re NASA

Much appreciated. Don't miss that post, folks
Timestamp above is 20:00

"... I had the opportunity to fly the Twin Otter with ice shapes on the tail, and I flew a demostration series of tailplane events. The Colgan case has none of the signatures of a tailplane stall, so far as I can tell...."
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Old 15th Feb 2009, 06:08
  #243 (permalink)  
 
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buffalo 300 accident

Many years while in a Shed(SD330) we suffered severe icing out of Amsterdam bound Newcastle at 9000ft(or so).
The Shed slowed up and we ended up with METO power but at 130 kts we had to start descending to maintain 130 kts.
We did not lower flap but continued in an uncontrolled descent down to about 3000ft where the OAT became 0 degrees and increasing.
At 1800 ft our descent arrested and slowly the Shed picked up speed so we diverted to Humberside.( the nearest airport) My F/O was an African who kept calling me '
"Boss"
Upon landing, and at the teminal it was observed that there was about a foot(12inches(300mm) of ice along the top of the fuselage.
The wing were nearly clear but had odd ice patches, and the empanage was clear.
The deicing boots were operating but in subsequent checks it was found that the wing boots had some leaks, so when tested without soapy water the boots inflated and deflated with apparent correct operation.
Put some ice on the boots and the leaks were severe enough to prevent the inflation, so the ice removal did not happen.
If Maintenance had soaped the boots this would have been rectified.

Moral of story if in severe Icing, pour on the coal and maintain minimum safe Clean speed( flaps retracted) even if it means descending, over water no problems but over high reale -estate the poo starts to pong but what else can one do.
Tne Buffalo chap, and Chappess obviously run out of options and went in flat in a semi controlled attitude but uncontrollable descent.
Elevator stalling, blanketing etc is more speculative than beeing just heavy with ice and having the lift coefficient screwed up by the aerodynamic distortion generated by an ice build up.
But for the grace of God, there go many of us if the odds are against us.

BBG
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Old 15th Feb 2009, 06:08
  #244 (permalink)  
 
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Looks like the autopilot was disconnected about the same time the flaps were lowered to 15 according to information released Saturday by the NTSB. Suddenly, the stall spin 'theory' that was proposed earlier by Uncle Jay doesn't look so preposterous.

Dumb question, does the Dash have autothrottles? If so, would one normally go to manual thrust with the autopilot off?
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Old 15th Feb 2009, 07:53
  #245 (permalink)  
 
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In over 20,000 hrs of flying I have never had any training in tailplane stall. We had some MD80 aircraft that we were required to push the tail deice button before selecting landing flaps but never emphasized. We had an MD80 go to landing flaps and and it pitched over into a dive and they brought the flaps back up to control it so that must have been the tailplane stall. The MD80 was a pos airplane so thought it was because of the tiny elevator that wasn't adequate for the size of the aircraft.

Every pilot should read the post relating to this because Nobody teaches it that I know.
I gave a specific training session concerning this when the information was released around 1988-89 and on. I'm not sure if it is 87 model only or 83 too. To say nobody teaches it is not correct. I hope you were given the information around clear ice on the wings.
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Old 15th Feb 2009, 08:06
  #246 (permalink)  
 
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Does the Q400 have the same flap system as the smaller ones? Does it have the secondary flap drive that physically connects the flaps and prevents flap asymmetry? If it does then asymmetric flap would seem to be very unlikely.
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Old 15th Feb 2009, 08:28
  #247 (permalink)  
 
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The stick pusher should prevent a fully developed stall though shouldn't it? Or at least give it a good nudge in the right direction.
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Old 15th Feb 2009, 08:57
  #248 (permalink)  
 
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The Q400 doesn't have autothrottles.

r.e the Increase Ref Switch - It doesn't just add 20kt to the alpha protection and give you white reverse video on the ED if ice is detected, it also decreases the stall reference angle of attack for stick shake & push.
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Old 15th Feb 2009, 09:08
  #249 (permalink)  
 
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Does the Q400 have the same flap system as the smaller ones? Does it have the secondary flap drive that physically connects the flaps and prevents flap asymmetry?
Nope. Single shaft.. but the Flap Control Unit will detect asymmetry and stop the flaps moving if it detects a fault.
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Old 15th Feb 2009, 09:15
  #250 (permalink)  
 
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Tail plane stall

Most probably a Tail plane stall. Despite the excellent info provided by the NASA/NTSB (check youtube "tailplane stall video nasa"), not many even experienced pilots know about it or if the do, know how to recognize it and to respond to it.

selecting flaps is often the onset to a tailplane stall, which is a typical thing to do around the OM.

Instead of pushing the stick, in a tail stall you will have to pull hard and get the flaps back to original setting.Be very carefull with large power applications as they can make things worse.

With 1500 ft above the ground and having a full tailstall develop and not instantly recognizing it there will have been few options for survival.

Having flown the dash for many years, I am still surprised that most collegues do not know a thing about this issue, nor is it trained in the sim.

So we will keep on seeing a similar accident on fixed tailplane turboprops for many winters to come I am afraid.
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Old 15th Feb 2009, 09:30
  #251 (permalink)  
 
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Smile

I have several thousand hours on the 1-2-300 series. With the flap drive system it's highly unlikely that you would get an asymmetric flap situation, as it has a common drive system to both wings, as well as duplicated actuators to each flap surface (from memory). So, unless you have a dual actuator failure on a single flap surface it would be an extremely unlikely occurrence. The secondary flap drive system is a flex drive type setup. The "FLAP DRIVE" caution illuminates when this drive is under load. It has no effect on the system and the flaps will operate normally. (A no-dispatch item once landed).

On the Dashes that I've flown there is no warning system for the failure of a de-ice boot. The "DEICE PRESS" caution light only illuminates if the whole system pressure falls below a specific value (this can also happen at low torque settings before the bleed system switches from the LP compressor to the HP.

The failure of a single boot should not cause this to occur, as the system can supply much more air than is required to run the boots. The only easy way of knowing a boot is not functioning is by observing the full boot cycle on the captain's overhead panel. If there is less than 6psi in a boot, the light will not illuminate. If there is a major failure in a L or R system they can be isolated from one another, but as somebody alluded to, you must exit icing conditions ASAP.

The company I worked for when flying the Dash had quite specific procedures for regularly testing the system and selecting the props, de-ice boots, elevator horn heat, wing valve heat and engine intake bypass doors ON. Below 5 deg C and in visible moisture etc, the whole system was selected on. Obviously, this was before "actual" icing conditions would be encountered and provided a measure of protection from the element of surprise.

The horizontal/vertical stab on the Dash has 2 boots per surface operating off 2 separate circuits for redundancy.

Somebody asked about autopilot and trim on the elevator. The Dash has no electric trim on the elevator except when the autopilot is engaged. It does the job reasonably well. If there is a mistrim in the autopilot you will get an amber message on the ID802 display. If the aircraft is in trim when disengaging the autopilot there is NO change in stick force.

I used to rest my right leg against the trim wheel when on autopilot so I could feel when it was trimming the elevator. Not for any particular reason.

In my experience the Dash could carry a lot of ice, and exhibited very docile handling characteristics even when quite iced up (from a southern hemisphere point of view). As for tailplane stall, we were trained in recognition of its onset and techniques to escape. (Not that the Dash was prone to tail stall).

Hope this helps.
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Old 15th Feb 2009, 10:00
  #252 (permalink)  
 
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Can someone describe the static source position and protection on this aircraft ? .. shakers and pushers imply to me that it reached a conventionally stalled condition................ following a descent in icing conditions.

Post 243 is suggesting similar I think

Last edited by Teddy Robinson; 15th Feb 2009 at 10:12. Reason: Previous post reference
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Old 15th Feb 2009, 10:05
  #253 (permalink)  
 
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Originally Posted by Hugh Jarse
Somebody asked about autopilot and trim on the elevator. The Dash has no electric trim on the elevator except when the autopilot is engaged. It does the job reasonably well. If there is a mistrim in the autopilot you will get an amber message on the ID802 display. If the aircraft is in trim when disengaging the autopilot there is NO change in stick force.
That's not quite true. The Dash 8 100/200/300 has an electric standby elevator trim which is activated by a guarded switch. This is not used in normal operations though.

I used to rest my right leg against the trim wheel when on autopilot so I could feel when it was trimming the elevator. Not for any particular reason.
I normally do it just because it's how my legs sit when I'm lounging. I then end up getting a mis-trim message on the advisory display as the autopilot struggles to over-ride my leg.
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Old 15th Feb 2009, 10:48
  #254 (permalink)  
 
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Huge Jarse,

Sorry to pick you apart. The DE ICE caution DOES indicate when you fail to get inflation on a single boot. Certainly did to me last week anyhow. A single boot that doesn't reach correct pressure sets it off, and you isolate the sides to determine which boot it is. The fault is commensurate with the light above the LHS flickering or not coming on at all.

As it happens, this was visually observed as a patch coming loose on the LHS outer section, that was glued back down on the next turnaround.

Fault finding of the system is pretty easy, in that you can narrow it down to one boot easily enough.

However, once in ICE, you then have to work hard to either make sure the contamination is symetrical or go somewhere wher the ice will melt and come off on it's own.

I've tried to dead stick in the sim, usual last 5 minute games, and the Q400 sim can't model this. Once both the hydraulic systems drop after you feather both props, it goes into a flat spin, and it's very disturbing, as nothing you do can alter it.

If, I stress IF, it turns out that the crew acted as per the NASA advice, when encountering an INCIPIENT tail stall, and their actions, i.e. reduce speed/power and re-configure immediately to previous settings, led to a wing stall and subsequent falt spin-out, then it bears very sobering reading for all of us TP drivers.

HOWEVER, the full NTSB report will give the answers, not conjecture on here. In the modern era of news by the minute, it's just not fashionable to sit and wait for proper investigations to be completed. This can often mean the wrong, or misleading answers go out in the public domain. More still, reputations can be tarnished or destroyed unfairly.

Please, just wait for the full report. The NTSB will work every hour there is to get this out quickly, they are fully aware of the seriousness of it, the implications and the fact so many other TPs are out there at this time of year, hoovering up the ice around regional airports.

Those of us flying the Uberdash will no doubt get company advice within a weeek or two.
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Old 15th Feb 2009, 10:51
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Aerocat,

The info on the classic Dashes has absolutely no relevance to the systems on the 400. It is a totally different a/c, with a totally different trim system.

The only commonality the 400 has with the classic Dash series is nothing more than a marketing fudge to sell more aeroplanes. It should have been given a different type rating altogether.

Trying to explain this accident by reference to the classic is about as much use as trying to explain it by reference to a Piper Warrior.
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Old 15th Feb 2009, 11:02
  #256 (permalink)  
 
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Aerocat,

The info on the classic Dashes has absolutely no relevance to the systems on the 400. It is a totally different a/c, with a totally different trim system.
I was replying to Hugh Jarse who was talking about the classic Dash 8. The relevance is to his post not the 400.
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Old 15th Feb 2009, 11:04
  #257 (permalink)  

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Dash & Thump - very well said.
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Old 15th Feb 2009, 12:58
  #258 (permalink)  
 
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Please forgive me if this is a dupe, but there are too many posts to go through.

Air Safety
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Old 15th Feb 2009, 13:27
  #259 (permalink)  
 
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That excellent NASA video explicitly recommends hand-flying through icing conditions, and yet this aircraft was using the autopilot up until flap extension. I have read the whole thread but I recall no reference to why they should have been using the autopilot. Is it permitted/recommended in the Q400 manual?
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Old 15th Feb 2009, 13:36
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The autopilot on the Q400 can be used in Icing conditions, infact the only situation where the autopilot cannot be used is a single engine approach.
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