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Buffalo Q400 crash



 
 
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  #1  
Old May 12th 09, 08:46 PM posted to rec.aviation.piloting
Don[_5_]
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Posts: 3
Default Buffalo Q400 crash

Just reading the WSJ reports on today's NTSB hearing concerning the
Q400 accident in Buffalo. I am not a pilot -- I know just enough about
flying to be dangerous. But I have a question for you folks who do
have real knowledge of aviation.

The transcript of the cockpit voice recorder says that once the
emergency began and they knew they were in serious trouble, the co-
pilot informed the pilot that she had "put the flaps up", 13 seconds
after the captain had lowered them to 15 degrees for landing. If stall
warnings and stick shakers/pushers are screaming at you that you are
in danger of stalling, isn't raising the flaps one of the worst things
you can do, since it *increases* your stall speed? In other words, if
you are already too slow with the flaps down, then you are *reallY*
too slow with them up. I would think they should have left the flaps
where they were, the nose where the stick pusher had it and just
poured on the power in the hope of gaining altitude before they hit
anything.

Am I right? Or, if not, please explain why.

Thanks --
/Don Allen
  #2  
Old May 12th 09, 08:55 PM posted to rec.aviation.piloting
[email protected]
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Posts: 684
Default Buffalo Q400 crash

On May 12, 1:46*pm, Don wrote:
Just reading the WSJ reports on today's NTSB hearing concerning the
Q400 accident in Buffalo. I am not a pilot -- I know just enough about
flying to be dangerous. But I have a question for you folks who do
have real knowledge of aviation.

The transcript of the cockpit voice recorder says that once the
emergency began and they knew they were in serious trouble, the co-
pilot informed the pilot that she had "put the flaps up", 13 seconds
after the captain had lowered them to 15 degrees for landing. If stall
warnings and stick shakers/pushers are screaming at you that you are
in danger of stalling, isn't raising the flaps one of the worst things
you can do, since it *increases* your stall speed? In other words, if
you are already too slow with the flaps down, then you are *reallY*
too slow with them up. I would think they should have left the flaps
where they were, the nose where the stick pusher had it and just
poured on the power in the hope of gaining altitude before they hit
anything.

Am I right? Or, if not, please explain why.

Thanks --
/Don Allen


Don,

Standard practice is to wait until you have a positive rate of climb
before raising the flaps. Raising the flaps if the airplane was on
the verge of a stall would be a big mistake. Lowering the nose and
applying full power would be the best course of action, and once a
positive rate of climb could be achieved, then the flaps could be
raised.
  #4  
Old May 13th 09, 01:55 AM posted to rec.aviation.piloting
[email protected]
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Posts: 684
Default Buffalo Q400 crash

On May 12, 2:57*pm, James Robinson wrote:
wrote:

Standard practice is to wait until you have a positive rate of climb
before raising the flaps. *Raising the flaps if the airplane was on
the verge of a stall would be a big mistake. *Lowering the nose and
applying full power would be the best course of action, and once a
positive rate of climb could be achieved, then the flaps could be
raised.


There is some debate about that. *For a wing stall, you are correct,
however, some have pointed out that the PIC's experience was recently on
Saabs, which can see tail stalls in icing conditions - the Q400 isn't
subject to tail stalls. *A tail stall is most often first seen when the
flaps are extended, and the effect is for the nose to drop. *The reaction
to a tail stall is to retract the flaps, and pull the nose up. *Was that
what the captain was reacting to?


If that is the case, he had no business flying the Q400 because he
lacked sufficient training in type.
  #5  
Old May 13th 09, 02:59 AM posted to rec.aviation.piloting
James Robinson
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Posts: 180
Default Buffalo Q400 crash

wrote:

James Robinson wrote:

*For a wing stall, you are correct, however, some have pointed out
that the PIC's experience was recently on Saabs, which can see tail
stalls in icing conditions - the Q400 isn't subject to tail stalls.
*A tail stall is most often first seen when the flaps are extended,
and the effect is for the nose to drop. *The reaction to a tail stall
is to retract the flaps, and pull the nose up. *Was that what the
captain was reacting to?


If that is the case, he had no business flying the Q400 because he
lacked sufficient training in type.


Listening to the NTSB hearings today, the Colgan chief pilots went to
great pains to say that they meet all FAA minimum training requirements.
They admitted that their training for the stick pusher was only in the
classroom prior to the accident, and that they never ran simulator
exercises to demonstrate how it worked. That seems like they missed the
mark with something that important. They changed their training after the
accident to include stick pusher simulations.

The Bombardier reps said that the aircraft isn't subject to tail stalls
in icing, but that it really isn't written anywhere in their flight
manuals. In fact, there was an error in one manual, where they recommend
training in tail stalls.

However, reading the cockpit transcripts suggests that the crew was less
than confident about flying in icing conditions. The first officer in
fact said that prior to her recent assignment to the northeast, all of
her flying had been out of Phoenix, and she had never flown when there
was ice buildup. She anticipated being upgraded to Saabs within six
months.

Overall, the crew was pretty lackadasical about procedures, and the first
officer seemed right out of her depth. Certainly not a seasoned
professional. The drop in airspeed was unnoticed, and the stall seemed to
catch them completely by surprise. One of the board asked each of the
Colgan check pilots to define "situational awareness", then made a speech
about how the crew was missing that important concept.
  #6  
Old May 13th 09, 12:57 PM posted to rec.aviation.piloting
Robert Moore
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Posts: 134
Default Buffalo Q400 crash

James Robinson wrote
The drop in airspeed was unnoticed, and the stall seemed
to catch them completely by surprise.


I wonder what the stall warning was doing all of this time?

Bob Moore
  #7  
Old May 13th 09, 05:50 PM posted to rec.aviation.piloting
bod43
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Posts: 41
Default Buffalo Q400 crash

On 13 May, 12:57, Robert Moore wrote:
James Robinson *wrote

The drop in airspeed was unnoticed, and the stall seemed
to catch them completely by surprise.


I wonder what the stall warning was doing all of this time?

Bob Moore


It appears that it was the stall warning (stick shaker) that the
captain (pilot flying) reacted to.

The reaction was to immediately pull back pretty hard
quickly precipitating an actual stall. 80% power was also
selected immediately. The stick was held back pretty much
until impact.

There is a simulated video on the NTSB web site. Web site
seems a bit busy at the moment.

They appear to have been decelerating towards 119 knots
in preparation for final approach when the stick shaker went off
unexpectedly at 139 knots. They may have forgotten that the
stall warning was set to trigger at a higher than normal
airspeed due to the aircraft being configured
partly for icing conditions.

If the reaction to the stick shaker had been to merely
stop the deceleration there would it seems have been no crash.

  #8  
Old May 13th 09, 06:33 PM posted to rec.aviation.piloting
James Robinson
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Posts: 180
Default Buffalo Q400 crash

Robert Moore wrote:

James Robinson wrote

The drop in airspeed was unnoticed, and the stall seemed
to catch them completely by surprise.


I wonder what the stall warning was doing all of this time?


The FDR data is posted on the NTSB web site, in both graphical and text
form. Here's a link to the graphical data:

http://www.ntsb.gov/Dockets/Aviation...027/417236.pdf

Looking at the graphs, the aircraft settled in at 2400 ft pressure alt
(1650 ft radio alt) with AP on in heading mode. After leveling off, 5
deg flaps were selected, and the throttles were increased to about 30%
torque. Over the next minute, the airspeed slowly climbed from about 160
kts to about 190 kts.

The next significant event was the throttles were dropped to about 10
percent torque, and 5 seconds later gear down was selected. At the same
time, the AP switched from heading mode to LOC mode, as the localizer was
captured, still maintaining altitude.

Airspeed was initially dropping at 2 kts per second, and increased to
about 3 kts per second as the gear extended. The airspeed dropped to
about 130 knots over the next 25 seconds, and at the same time, the AP
steadily increased pitch from about 3 degrees to 10 degrees to maintain
altitude.

The next events happened in rapid succession:

- Ice detect alarm on (message flashes on display).
- Flaps increased to 10 degrees.
- 2 seconds after flap select, at about 130 kts, the stick shaker
activates (It is set to activate on low airspeed, indicating impending
stall.)
- 20 lbs. pull is shown on both left and right control columns in
response, and throttles are increased to 75% torque.
- Aircraft pitches up sharply, reaching 30 degrees over the next five
seconds.
- As the aircraft pitches up, the AP shuts off.
- 2 seconds after the start of the pitch-up, the aircraft rolls sharply
left, and the stick pusher is activated. The aircraft rolls 50 degrees
over 2 seconds. The stick pusher is triggered by high AOA, and indicates
that the aircraft has stalled.
- Both the rudder pedals and control wheels are in a neutral position
while this is happening, so the sudden roll is likely because of
differential ice accretion and the left wing stalling, as a guess.
- In response to the roll, the wheel is moved to the right, and the right
rudder pedal is pressed. The aircraft rolls from left 50 degrees to
right 100 degrees in 5 seconds.
- While the pitching and rolling is going on, airspeed is sitting at
about 100 kts, and the FO retracts the flaps on her own initiative.
- The right roll is overcorrected, and the aircraft rolls to 40 degrees
left, and then again rolls right to 100 degrees for a second time.
- Finally, the roll is stabilizing at 30 degrees right, but the aircraft
has pitched down by 45 degrees. They attempt to pull out of the dive,
pulling up to 2Gs with 170 lbs combined pull on both control columns.
(120 on left, 50 on right) but run out of altitude.
- Airspeed at the end of the recording is about 130 knots, pitch down at
25 degrees, power still at 75%, gear being retracted. Altitude loss is
900 feet in the last five seconds, with no sign of abatement. Overall
time from start of stick shaker to end of recording is about 25 seconds.

So where does this all end up? The crew was inattentive to the speed
loss, and everything hit them at once. They reacted the wrong way to the
impending stall by pulling the nose up and applying power, ending up with
a true power-on stall. Retracting the flaps and gear was also
questionable. The captain overreacted to the rolls making things worse,
and unrecoverable.

The NTSB is probably going to come down hard on the airline on crew
selection, training, and management oversight. They will also hit the
FAA for not having sufficient training and check requirements.

Overall, this will probably be a watershed accident for the regional
carriers, where many rules regarding hiring, training and proficiency
testing will be substantially tightened.
  #9  
Old May 13th 09, 07:14 PM posted to rec.aviation.piloting
Ron Garret
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Posts: 199
Default Buffalo Q400 crash

In article
,
bod43 wrote:

On 13 May, 12:57, Robert Moore wrote:
James Robinson *wrote

The drop in airspeed was unnoticed, and the stall seemed
to catch them completely by surprise.


I wonder what the stall warning was doing all of this time?

Bob Moore


It appears that it was the stall warning (stick shaker) that the
captain (pilot flying) reacted to.

The reaction was to immediately pull back pretty hard
quickly precipitating an actual stall. 80% power was also
selected immediately. The stick was held back pretty much
until impact.


This boggles my mind. I'm just a PP but throughout my training I've had
it drilled in to me to lower the nose on an impending stall. How can
any pilot not know that, let alone one who is getting paid to fly
passengers?

rg
  #10  
Old May 13th 09, 07:59 PM posted to rec.aviation.piloting
Mike Ash
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Posts: 299
Default Buffalo Q400 crash

In article ,
Ron Garret wrote:

In article
,
bod43 wrote:

On 13 May, 12:57, Robert Moore wrote:
James Robinson *wrote

The drop in airspeed was unnoticed, and the stall seemed
to catch them completely by surprise.

I wonder what the stall warning was doing all of this time?

Bob Moore


It appears that it was the stall warning (stick shaker) that the
captain (pilot flying) reacted to.

The reaction was to immediately pull back pretty hard
quickly precipitating an actual stall. 80% power was also
selected immediately. The stick was held back pretty much
until impact.


This boggles my mind. I'm just a PP but throughout my training I've had
it drilled in to me to lower the nose on an impending stall. How can
any pilot not know that, let alone one who is getting paid to fly
passengers?


Seconded. Stall warning, stick goes forward! Forward! Or whatever you
do, it does not go *back*! How can you get into the position of carrying
a bunch of passengers around for hire without knowing this?

I imagine the explanation not as simple as it appears. (The simple
explanation being "they were morons".) I'll be really interested to hear
just how their training got them to this point.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon
 




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