Continental TurboProp crash inbound for Buffalo
Join Date: Jun 2005
Location: Denmark
Posts: 142
Likes: 0
Received 0 Likes
on
0 Posts
Hi Flight Safety
Previously you suggested, that forward CG could have caused the pitch up.
Why would this happen. With the CG beyond forward limit, the more negative lift on the tail is required. Therefor a tail stall would lead to a pitch down movement instead.
Having said this, the Q400 will run out of forward trim more easily than aft trim - especially when full.
Cheers
SE210
Previously you suggested, that forward CG could have caused the pitch up.
Why would this happen. With the CG beyond forward limit, the more negative lift on the tail is required. Therefor a tail stall would lead to a pitch down movement instead.
Having said this, the Q400 will run out of forward trim more easily than aft trim - especially when full.
Cheers
SE210
Join Date: Jun 2005
Location: Denmark
Posts: 142
Likes: 0
Received 0 Likes
on
0 Posts
I just read, that the plane was going very slow on.
Selecting gear down at 134 knots is very slow on the Q400.
Then if you select flaps and do not apply power - then the speed is coming off very quickly.
The airplane got stick shaker followed by stick pusher. The stick push will put the nose down to around -30 degrees.
Apparently the pilot did override the push and pulled the nose up and applied full power. This resulted in a 31 degree pitch up and another stall, from which the aircraft could not be recovered.
The accident may not be related to ice at all.
Brgds
SE210
PS - I loved to fly the Q400, but it is the most tricky and unforgiving plane, I have flown. It can trick you very easily - especially with the speed, that can bleed off in a matter of seconds if you hessita with power.
Selecting gear down at 134 knots is very slow on the Q400.
Then if you select flaps and do not apply power - then the speed is coming off very quickly.
The airplane got stick shaker followed by stick pusher. The stick push will put the nose down to around -30 degrees.
Apparently the pilot did override the push and pulled the nose up and applied full power. This resulted in a 31 degree pitch up and another stall, from which the aircraft could not be recovered.
The accident may not be related to ice at all.
Brgds
SE210
PS - I loved to fly the Q400, but it is the most tricky and unforgiving plane, I have flown. It can trick you very easily - especially with the speed, that can bleed off in a matter of seconds if you hessita with power.
Join Date: Jan 2006
Location: The other London...
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
Minor point, but the Captain would have been new to full EFIS and speedtape specifically from what I gather, coming off the Saab 340 and partial EFIS. Not that big of a deal to get used to but throw fatigue and other distractions such as icing to the mix.....
Join Date: Jul 1999
Location: 58-33N. 00-18W. Peterborough UK
Posts: 3,040
Likes: 0
Received 0 Likes
on
0 Posts
I know I‘ll regret posting this - but I remember laughing when someone claimed that Colour Wx Radar was on the way in. 
In the meantime I’ve seen almost every new widget as it found its way onto aircraft. What I’ve never seen (talking no auto throttle here) is a simple Voice Callout of airspeed derived from a bug setting on the ASI. Set a minimum for 'standard' Ops at the time, massage the call out triggers with Fuel Quantity, De-Ice on or off, etc etc. Well?
In the meantime I’ve seen almost every new widget as it found its way onto aircraft. What I’ve never seen (talking no auto throttle here) is a simple Voice Callout of airspeed derived from a bug setting on the ASI. Set a minimum for 'standard' Ops at the time, massage the call out triggers with Fuel Quantity, De-Ice on or off, etc etc. Well?
Join Date: Jan 2008
Location: Denmark
Age: 79
Posts: 158
Likes: 0
Received 0 Likes
on
0 Posts
134 kts versus incr. ref. switch??
Acc. info in #520 the gear and flaps were selected down at 134 kts.
Also it is reported that the incr. reference switch was ON - thereby increasing the speed at which the stickshaker/stickpusher are activated.
Acc. #508:
Vref FL. 0 is 143 - same as 1.23 X Vs. Vs is then 116 kts
(Vref FL. 10 is 122 - - - - Vs is then 99 kts)
Acc, an earlier post the threshold for activation of the stickshaker is Vs plus 3 kts.
So, if you are flying clean in no icing conditions the stickshaker should operate at 119 kts.
BUT IF YOU ARE IN ICING CONDITION (SWITCH ON) THE SPEED WOULD BE 139 kts! (plus 20 kts)
So, if flying clean at 134 kts in icing conditions you would have activated the stickshaker!
So there are 3 possibilities: a) My calculations are incorrect. b) They flew faster than 134 kts. c) The incr. ref. switch was not ON.
I am puzzled
Somebody enlighten me!
brgds
Also it is reported that the incr. reference switch was ON - thereby increasing the speed at which the stickshaker/stickpusher are activated.
Acc. #508:
Vref FL. 0 is 143 - same as 1.23 X Vs. Vs is then 116 kts
(Vref FL. 10 is 122 - - - - Vs is then 99 kts)
Acc, an earlier post the threshold for activation of the stickshaker is Vs plus 3 kts.
So, if you are flying clean in no icing conditions the stickshaker should operate at 119 kts.
BUT IF YOU ARE IN ICING CONDITION (SWITCH ON) THE SPEED WOULD BE 139 kts! (plus 20 kts)
So, if flying clean at 134 kts in icing conditions you would have activated the stickshaker!
So there are 3 possibilities: a) My calculations are incorrect. b) They flew faster than 134 kts. c) The incr. ref. switch was not ON.
I am puzzled
Somebody enlighten me!brgds
Last edited by grebllaw123d; 18th Feb 2009 at 21:09.
Join Date: Dec 2005
Location: At home
Posts: 244
Likes: 0
Received 0 Likes
on
0 Posts
forget
I guess the problem is that there may always happen some distraction that diverts the pilots' attention and makes him/her deaf to any voice warnings.
For example this classic explanation after a gear-up landing: "There was some d*mn horn blaring too loud and distracting me from doing the landing checks"
For example this classic explanation after a gear-up landing: "There was some d*mn horn blaring too loud and distracting me from doing the landing checks"
Join Date: Dec 2001
Location: London
Posts: 186
Likes: 0
Received 0 Likes
on
0 Posts
FS: The Wall Street Journal has already identified the last of your scenarios as the actual one, citing "people familiar with the situation", IOW probably NTSB people on an off-the-record basis.
"The commuter plane slowed to an unsafe speed as it approached the airport, causing an automatic stall warning, these people said. The pilot pulled back sharply on the plane's controls and added power instead of following the proper procedure of pushing forward to lower the plane's nose to regain speed, they said. He held the controls there, locking the airplane into a deadly stall, they added."
"The commuter plane slowed to an unsafe speed as it approached the airport, causing an automatic stall warning, these people said. The pilot pulled back sharply on the plane's controls and added power instead of following the proper procedure of pushing forward to lower the plane's nose to regain speed, they said. He held the controls there, locking the airplane into a deadly stall, they added."
Join Date: Jan 2001
Location: Dallas, TX USA
Posts: 739
Likes: 0
Received 0 Likes
on
0 Posts
Frangible, the WSJ article states the events happened in a different sequence from what I understand, but I'm not saying my understanding is correct. Their story is also asking me to believe that two professional pilots not only made one dumb mistake, but made two in very quick sequence (letting the airspeed decay to a stall during a configuration change, and then pulling BACK on the yoke to recover from it). They'd have to be idiots to do that, and I find that very hard to believe (at least for now).
SE210, not very likely I admit. However I don't know what ice on the bottom of the wing (past the boots, possibly acquired during the lower airspeed at a higher AOA) does to the aerodynamics.
grebllaw123d, the NTSB has stated they are not fully confident in that number yet, so they might have been flying at a somewhat higher airspeed, but who knows at this point.
SE210, not very likely I admit. However I don't know what ice on the bottom of the wing (past the boots, possibly acquired during the lower airspeed at a higher AOA) does to the aerodynamics.
grebllaw123d, the NTSB has stated they are not fully confident in that number yet, so they might have been flying at a somewhat higher airspeed, but who knows at this point.
Last edited by Flight Safety; 18th Feb 2009 at 20:58.
Join Date: Jan 2009
Location: alameda
Posts: 1,053
Likes: 0
Received 0 Likes
on
0 Posts
IF it was pilot error and the crew allowed the plane to get too slow, THEN better stall warning must be included into the plane's equipment. Instead of a shaker and a pusher...better put in a HORN, then shaker then pusher.
Every place I've flown, the full attention of the crew is to be focused on the level off during the last 1000'.
Because the NTSB is still unsure about the airspeed, I suspect that something unusual happened to it.
Every place I've flown, the full attention of the crew is to be focused on the level off during the last 1000'.
Because the NTSB is still unsure about the airspeed, I suspect that something unusual happened to it.
Join Date: Dec 2000
Location: I used to know
Posts: 175
Likes: 0
Received 0 Likes
on
0 Posts
Ref speeds
Just to clarify the speeds I quoted at post 508 were for a landing weight of 24000kg and used to ilustrate the dangers of low speed - why 24tons? - aprox 18000kg Aircraft dow + 4000kg pax + 2000kg fuel = 24000kg.
Acording to post 655 the ntsb are quoting a vref of 119kts. we do not know if that is for flap 15 or 35 but in either case is for a landing weight greater than 24000kg.
This does make my figures conservative as with inc ref on, the adjusted vref would be Flap 15 = 139kts and flap 35 = 134kts.
Q How easy is it to become distracted and not increase power on level off? A Very.
probably far more on this thread than we care to admit have had a oh F
K moment.
Acording to post 655 the ntsb are quoting a vref of 119kts. we do not know if that is for flap 15 or 35 but in either case is for a landing weight greater than 24000kg.
This does make my figures conservative as with inc ref on, the adjusted vref would be Flap 15 = 139kts and flap 35 = 134kts.
Q How easy is it to become distracted and not increase power on level off? A Very.
probably far more on this thread than we care to admit have had a oh F
K moment.
Join Date: Jan 2008
Location: Sonoma, CA, USA
Age: 79
Posts: 143
Likes: 0
Received 0 Likes
on
0 Posts
Re: 666 (how appropriate)
I loved to fly the Q400, but it is the most tricky and unforgiving plane, I have flown.
How could someone 'love' to fly an airplane with that kind of performance?!
I loved flying the Pitts Special. The bad things about it made it a challenge and added to my enjoyment of it.
Join Date: Feb 2009
Location: TX
Age: 52
Posts: 20
Likes: 0
Received 0 Likes
on
0 Posts
Colgan
New here (not to aviation!) and interested in your discussion. I have been going over (and over) this scenario as well.
A number of you remark the slow airspeed. I agree 134kts seems slow even if no ice. Post 669: the reference speed ice adjust switch could have set off stick shaker. And another few knots, push?
What I would like to ask you is:
- does anyone have the exact sequence of events from the NTSB? Sorry, I didn't read all 600 or so posts and the news reports are not worth their weight in ink (or e-ink).
I am bothered by the incredible roll "upset" upon deployment of flaps in particular. Did the stick shaker go off before this event?
Keep in mind that I ask for some input just to learn. I have incredible respect for the crew regardless of any report/opinion and join you in mourning their loss
A number of you remark the slow airspeed. I agree 134kts seems slow even if no ice. Post 669: the reference speed ice adjust switch could have set off stick shaker. And another few knots, push?
What I would like to ask you is:
- does anyone have the exact sequence of events from the NTSB? Sorry, I didn't read all 600 or so posts and the news reports are not worth their weight in ink (or e-ink).
I am bothered by the incredible roll "upset" upon deployment of flaps in particular. Did the stick shaker go off before this event?
Keep in mind that I ask for some input just to learn. I have incredible respect for the crew regardless of any report/opinion and join you in mourning their loss
The psychologists have established that when we get "maxed out" we delete aural inputs - in other words the ear senses sound but the brain doesn't perceive it. There have been incidents where the non flying pilot has been calling "Airspeed" but the flying pilot has taken no action for this reason. So the non flying pilot may have to break the flying pilot's pattern by shaking him on the shoulder (for example) or even, in extremis, moving the flying controls/thrust levers etc.
Aerocat stoof - but a Pitts is supposed to be a handful.
I'll end the hijack here, lest the posts start getting deleted again.
A 'gotcha' with the Q400 is the sensitive lower end of the throttle quadrant and unsensitive upper end of the quadrant.
Eg flight idle to 30% Tq is a very small movement
50% Tq to the dentent (selected max power NTOP, MCL, MCR etc) is a much larger movement
Setting the power by 'sound and feel' at this lower end of the quadrant is out of the question with low hours on type.
Fully configured for landing a Tq setting of 14-30% is normal depending on the flap setting
Eg flight idle to 30% Tq is a very small movement
50% Tq to the dentent (selected max power NTOP, MCL, MCR etc) is a much larger movement
Setting the power by 'sound and feel' at this lower end of the quadrant is out of the question with low hours on type.
Fully configured for landing a Tq setting of 14-30% is normal depending on the flap setting