Originally posted by Evan
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Colgan DHC-8 crashed in Buffalo
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Originally posted by Evan View PostI think the question is, did he realize he was doing that? Fighting the stick-pusher and unaccustomed to the sensitive hydraulic elevator, and all the while believing he was fighting an ice-laden tailplane, I think he may have become disoriented and unaware of the amount of pitch he was commanding (he would have considered the elevator to be compromised). It was dark. He was used to the direct feel of the mechanical elevator. Shades of AA587 perhaps. I have to reread the investigation report and the CVR. It's been a while. Do you have a link to it?
THE STICK PUSHER FLOLOWED THE PILOT'S PULL UP, not the other way around.
So, again: Why did the pilot PULL UP so badly in the first place?
It cannot be that he confused the stick pusher with a tail stall because the stick pusher didn't kick in until a few seconds AFTER the pull-up.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostEvan, once again, and for the last time (if you don't get it now):
THE STICK PUSHER FLOLOWED THE PILOT'S PULL UP, not the other way around.
So, again: Why did the pilot PULL UP so badly in the first place?
It cannot be that he confused the stick pusher with a tail stall because the stick pusher didn't kick in until a few seconds AFTER the pull-up.
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Originally posted by Arrow View PostParlour-talker here (unapologetically so). How does one become a PIC with 261 hours? As one of the sheep, that says to me that we have someone at the controls who's only nominally more qualified than the guy huckin' the baggage. Given the clearly incorrect response to a given situation, how valid was his transition to PIC?
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Originally posted by Gabriel View PostTHE STICK PUSHER FLOLOWED THE PILOT'S PULL UP, not the other way around.
So, again: Why did the pilot PULL UP so badly in the first place?
It cannot be that he confused the stick pusher with a tail stall because the stick pusher didn't kick in until a few seconds AFTER the pull-up.
Originally posted by Flightglobal.comNTSB: Colgan 3407 pitched up despite anti-stall push
By John Croft
Flight data recorder information shows the Colgan Air Q400 that crashed in Buffalo Thursday night pitched 31 degrees nose-up after stick shaker and stick pusher systems activated at the start of the instrument approach.
The events occurred as the crew began configuring the twin-engine turboprop for landing in light to moderate icing and snow conditions.
According to National Transportation Safety Board (NTSB) member Steven Chealander, data shows that the stick shaker and stick pusher activated roughly 34 seconds after the landing gear was deployed and as the wing flaps transitioned between 5 and 10 degrees down. The pilots had commanded the flaps to the 15 degree down position.
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Originally posted by Evan View PostGabriel, not necessarily disputing you, but once again, can you post a link to that information?
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Evan View PostGabriel, this is what I have. If you have some update to this that I don't know about please post. ASAIK, there has been no definition of events beyond this, and the indication is that the pilot pulled up AFTER the stick pusher pulled away from him:
Enjoy (if you have the patience)
By the way, the news report yopu quoted is misleading but factually correct as the 31 deg pitch up was achieved after the stick shaker, after the pull up, after the stick pusher, and after the pilot kept pulling up against it, in that order.
What's misleading there is the absolute omision of any reference of the pilot's action of pulling up, which is in fact what caused the pitch up, and what caused the stick pusher activation too.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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If the animation sequence is accurate I can see that the stick pusher had nothing to do with the pitch up. I still think Renslow might have had an instinct that didn't account for the Q400 control sensitivity. The DHC-8 AFM approach to stall procedure calls for 12° ANU and max power, and he gave it 31° and max power, but also notice the extreme rudder deflection just then.
Also, I'm wondering if Renslow was caught by surprise when the A/P disengaged (he obviously wasn't expecting this at 134 kts because he wasn't watching the barberpole on the speed tape—which is the initial cause of this accident) and was in a physical position that applied momentary back pressure on the yoke or exacerbated his pitch controls at that moment:
22:14:22.6 HOT-1
alright let's see if I can get this seat...siteated...that's alright there.
22:14:24.7 CAM
[sound similar to seat track movement]
22:14:32.7 HOT-1
still trying to find that sweet spot I guess there *.
OK, that's clutching at straws.
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Originally posted by Evan View PostIf the animation sequence is accurate...
This is as accurate and trustable as you will ever get.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Relating to this crash, Frontline will air a new edition on February 9th called "Flying Cheap"-the following video is a 10-minute excerpt from that:
One year after the deadly airline crash of Continental 3407 in Buffalo, NY, FRONTLINE investigates the accident and discovers a dramatically changed airline industry, where regional carriers now account for half of the nation's daily departures. The rise of the regionals and arrival of low-cost carriers have been a huge boon to consumers, and the industry insists that the skies remain safe. But many insiders are worried that now, 30 years after airline deregulation, the aviation system is being stretched beyond its capacity to deliver service that is both cheap and safe.
I feel less safe about flying in a regional airliner after watching that. Honestly, the guy from the Regional Airlines Association sounds like he's just reading from cue cards; the pilots seem a lot more honest.
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Originally posted by Fear_of_FlyingI think he only gave it 80% power.
From what I've recently learned, here and elsewhere, I'm back to this:
Even flying on A/P, the Q400 has no autothrottle and depends on the crew to closely monitor power settings on approach. They neglected to do this and let the airspeed decay to a dangerously low margin, ref switch or no ref switch. Obviously they were not monitoring airspeed because with the ref switch enabled, the barberpole was right there. This seems to be the primary cause of the crash.
HOWEVER - unless significant icing was present, they still had a 20kt margin above Vref and were in no immediate danger of stalling. And in any case this should never bring down a state of the art aircraft. The Q400 has stall protections and a TOGA switch and is powerful enough to fly out of an impending stall if piloted correctly. The approach to stall procedure for the Q400 is apparently the same as the go-around procedure. Increase pitch, retract flaps and gear and go to max power.
BUT - Renslow had nowhere near the amount of experience on type needed to be PIC on the Q400. He probably had very little hand-flying time on the Q400 or on aircraft with powered control surfaces (the full right-rudder deflection was probably evidence of this) and lacked sufficient training for stall prevention/recovery on type. Because of this, the stall protections may have actually contributed to the confusion and therefore the crash.
MOREOVER - he had insufficient time on type to develop innate instincts for the aircraft in a split-second emergency. He probably had such instincts for the SAAB SF340, and he probably acted from those instead.
I no longer believe he read this as a tail stall because there was no initial pitch down and stick-shaker (elevated AOA) would not be the first sign of a tail-stall. Tail stalls also tend to occur at higher speeds.
I SUSPECT - he reacted wiith a conventional stall mentality but over-controlled due to being unaccustomed to powered control surfaces. Still, I assume there is a big difference in control input for 12° in the SAAB and 31° in the Q400. That is something I wish I knew more about. Just before the final roll, he seems to have brought the pitch back to where it should be.
Shaw also lacked experience in general. Her decision to retract flaps without command may have contributed to the flawed recovery. I'm no expert on this, but AFAIK flap reduction is the right move for the approach to stall procedure (as in a go around) but not in a developing stall where you are only raising Vs. Also, on the Q400, the rudder travel is limited to 12° in clean configuration. Could this have exacerbated Renslow's last efforts to recover?
BASICALLY - I'm seeing a scenario involving initial inattentiveness (either distraction or complacency), a phantom stall warning, situational confusion, compounded by lack of training on type, and the absence of a more type experienced PIC.
ANYWAY - This is my best attempt to deal with the perplexing question of how a moderately experienced pilot like Renslow could so rapidly end up in an accelerated stall on a very capable aircraft. Until this question is better answered, the investigation cannot be considered complete.
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Originally posted by Evan View PostYou sure? Somewhere, there is raw, unanimated DFDR data that would answer a few questions, such as that one. The Q400 lacks autothrottle (obviously) but it has a TOGA switch. Why wouldn't he use it?
From what I've recently learned, here and elsewhere, I'm back to this:
Even flying on A/P, the Q400 has no autothrottle and depends on the crew to closely monitor power settings on approach. They neglected to do this and let the airspeed decay to a dangerously low margin, ref switch or no ref switch. Obviously they were not monitoring airspeed because with the ref switch enabled, the barberpole was right there. This seems to be the primary cause of the crash.
HOWEVER - unless significant icing was present, they still had a 20kt margin above Vref and were in no immediate danger of stalling. And in any case this should never bring down a state of the art aircraft. The Q400 has stall protections and a TOGA switch and is powerful enough to fly out of an impending stall if piloted correctly. The approach to stall procedure for the Q400 is apparently the same as the go-around procedure. Increase pitch, retract flaps and gear and go to max power.
BUT - Renslow had nowhere near the amount of experience on type needed to be PIC on the Q400. He probably had very little hand-flying time on the Q400 or on aircraft with powered control surfaces (the full right-rudder deflection was probably evidence of this) and lacked sufficient training for stall prevention/recovery on type. Because of this, the stall protections may have actually contributed to the confusion and therefore the crash.
MOREOVER - he had insufficient time on type to develop innate instincts for the aircraft in a split-second emergency. He probably had such instincts for the SAAB SF340, and he probably acted from those instead.
I no longer believe he read this as a tail stall because there was no initial pitch down and stick-shaker (elevated AOA) would not be the first sign of a tail-stall. Tail stalls also tend to occur at higher speeds.
I SUSPECT - he reacted wiith a conventional stall mentality but over-controlled due to being unaccustomed to powered control surfaces. Still, I assume there is a big difference in control input for 12° in the SAAB and 31° in the Q400. That is something I wish I knew more about. Just before the final roll, he seems to have brought the pitch back to where it should be.
Shaw also lacked experience in general. Her decision to retract flaps without command may have contributed to the flawed recovery. I'm no expert on this, but AFAIK flap reduction is the right move for the approach to stall procedure (as in a go around) but not in a developing stall where you are only raising Vs. Also, on the Q400, the rudder travel is limited to 12° in clean configuration. Could this have exacerbated Renslow's last efforts to recover?
BASICALLY - I'm seeing a scenario involving initial inattentiveness (either distraction or complacency), a phantom stall warning, situational confusion, compounded by lack of training on type, and the absence of a more type experienced PIC.
ANYWAY - This is my best attempt to deal with the perplexing question of how a moderately experienced pilot like Renslow could so rapidly end up in an accelerated stall on a very capable aircraft. Until this question is better answered, the investigation cannot be considered complete.
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I wonder if we can really rule out engine trouble based on what many witnesses on the ground heard--
NTSB Dockets, File 431227--witness statements
pg2 of 131
Vicki Braun
...plane engine had ''echo sound'' then sounded like the engine stopped then heard a ''boom.''
pg6 of 131
Shannon Alessandra
Just prior to the airplane crashing, the engines made a ''weird sound.''
pg7 of 131
Jean Andreassen
Andreassen stated that she heard strange noises from the engines
pg8 of 131
Kristen and Aaron Archambeault
They both described the engine noise as ''sputtering''
pg11 of 131
Michele Beiter
Michele stated the noise 'skipped' and she was relieved it stopped, and then it started again. Michel is positive there was a skip. Michele further described everthing she heard as, 'Noise, skip, noise, loud noise.'
pg13 of 131
Robert Bijak
The engines sounded like a metallic rattle and remined Bijak of a car engine with no oil in it.
pg14 of 131
Tin Bojarski
The plane did not sound right and sort of sounded like a car with a broken muffler.
pg17 of 131
Ronald Braunscheidel
...he heard a very loud spitting and sputtering sound of a plane engine flying overhead. Braunscheidel described the noise as a car without a muffler.
pg 18 of 131
Sharon Brennan
Brennan believed the plane was... maybe in trouble based on the noise.
pg28 of 131
Dan Cizdziel
...heard a sputtering, binging noise to the north....
pg42 of 131
Doug Errick
Errick indicated that as the plane got closer the engines became very rough. Errick thought the engines were coming on and off, almost like engines were trying to come back on, but couldn't remain running. Errick thought the engines were changing RPMs rapidly.
pg49 of 131
Mary Grefrath
Grefrath recalled that the engine sounded like it was spuddering.
pg66 of 131
Jean Larocque
Larocque... stated he heard puttering plane... Larocque reported that the engines were not making a uniform sound.
pg 77 of 131
Molly Merlo
...she heard the airplane make a ''gurgling'' sound.
pg81 of 131
Marianne Neri
The engine noise did not sound like a normal plane, but more like a helicopter. It was obvious something was wrong with the engines.
pg85 of 131
Angela Pillo
The sound was very loud and ''rough,'' as if the engine was having trouble. The sound was further described as sounding like a ''lawn mower''
pg91 of 131
Lisa Rott
....she heard a consistent low grumbling sound that she believed to be a propeller plane. Rott advised that the sound the plane's engines was not smooth and did not sound like other propeller planes that she has heard in the past.
pg96 of 131
Kenneth Smith
...heard a big bag then continued to hear the sound of airplane engines.
pg89 of 131
Joseph Summers
...heard a plane which was very low and didn't sound normal. Mr. Summers cited a ''rambling noise'' which sounded as if an engine was not running properly.
pg101 of 131
Rick Telfair
Telfair stated he then heard a winding or grinding noise, then a screeching or grinding noise and approximately 20-30 seconds later heard a large boom... Telfair further described the noise of the engine as fighting, almost as though they were trying to go faster but couldn't, not accelerating but distressed.
pg 102 of 131
Denise Trabucco
Trabucco described the sound as a humming, similar to a transformer prior to it blowing. Aafter the humming, Trabucco heard a popping sound. ... About a minute after the humming and popping sound, Trabucco and her family felt a vibration that felt a little like an earthquake.
pg105 of 131
Lorraine Unverzart
The airplane engines made a ''chugging'' sound, similar to a ''spark plug misfiring.''
pg106 of 131
Louis Vitello
...he heard the plane engines sputtering as it approached, and then heard a ''popping sound.'' Immediately after that Mr. Vitello heard ''grinding'' noised, stating that the noises reminded him of gears grinding together, sounding like the gears were missing teeth.
pg124 of 131
David Wolf
...the engines were making an unusual ''shuttering'' sound
pg126 of 131
Melissa Wols
She stated she heard the plane.... grinding and sputtering as it approached and passed over his residence. Wols advised it sounded similar to what grinding metal would sound like.
pg129 of 131
Rita Zirnheld
It ''sounded like spttering'' and ''engine was coughing.''
pg130 of 131
Barbara Garrett
She said the plane engine was making loud noises, as though metal was banging and clattering.
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Renslow had nowhere near the amount of experience on type needed to be PIC on the Q400
Thousands of pilots every year who are Captains on one type become Captain on another type having never flown it as an F/O, and it doesn't result in crashes. Thats what training is about. Having a high standard of F/O's is also very helpful.
I'm no expert on this, but AFAIK flap reduction is the right move for the approach to stall procedure (as in a go around) but not in a developing stall where you are only raising Vs. Also, on the Q400, the rudder travel is limited to 12° in clean configuration. Could this have exacerbated Renslow's last efforts to recover?
As to the rudder - I'm not sure about the Q400, but certainly on jet types it should not be used during an approach to, or stall, recovery. It usually ends up making the situation worse, and possibly inducing a spin, due to its powerful nature.
Starviego - Its important to remember that these noises they heard may have been AFTER the aircraft stalled, and airflow over the props was disrupted not long prior to the crash.
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As to the rudder - I'm not sure about the Q400, but certainly on jet types it should not be used during an approach to, or stall, recovery. It usually ends up making the situation worse, and possibly inducing a spin, due to its powerful nature.
That means a strong left yawing effect due to the P factor that would need appropiate ammounts of right rudder to coutneract. Most likelly not full deflection though.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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