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

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.

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?

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.

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.

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

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.

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/DCA09MA027/417236.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.

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

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

In article >,
says...
> 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.

Quite incredible really. What pilot on planet earth does that man!

--
Duncan

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.

There was a theory on one of the other pilot forums that the captain
might have done all of his stall training when the aircraft was under
manual control, untrimmed, with the throttles cut until the speed dropped
below stall speed. He might have gotten used to having some backpressure
on the control column to avoid altitude loss under those conditions.

He might never have experienced stall training where the AP had ratcheted
the pitch trim toward its maximum, and was caught by surprise with the
sudden pitch up when the AP kicked off.

The FDR shows his immediate reaction to the stick shaker was to apply 20
lbs backpressure, which he immediately let go of as the aircraft pitched
up. He never pushed on the control column, however the wild
left/right/left/right rolls pretty well made controlling pitch a moot
point.

One curious thing about the FDR data is that it shows 20/25 lbs
backpressure on the control columns on both sides immediately after the
stick shaker fired, with the force on the #2 side the higher of the two.
Did both the captain and FO react by pulling up? Did the FO yank on the
control column at the worst time to steady herself because her seat moved
on the track? Very strange.

Not sure I buy it, but an interesting theory about stall training.

On May 13, 2:14*pm, 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?

It may boggle the mind of a PP like you (or me for that matter) who
seldom or never flies in icing conditions. However in icing
conditions a tail stall is possible, and the recovery from that is
exactly what this flight crew did. Yes, I know the Q400 is alleged
not to be suspectible to this but the captain had just come from a
type that is, and the FO spent a good part of the five minutes before
the crash chatting about how she feared icing, had never experienced
it before, and how would she handle it, etc. So then after chatting
and worrying about icing, they got something that felt/looked like it
could be an ice-induced tail stall and since it was on their minds
they did the recovery from that. They acted on instinct and it was
the wrong instinct. IMO.

This crew has come in for lots of criticism and I think a lot of it,
especially on their attentiveness and lack of discipline, appears to
be well-deserved, but there comes a point where it just becomes piling
on.

On May 14, 1:03*pm, xyzzy > wrote:
>
> This crew has come in for lots of criticism and I think a lot of it,
> especially on their attentiveness and lack of discipline, appears to
> be well-deserved, but there comes a point where it just becomes piling
> on.

Yeah, but it has to pile pretty high and get pretty loud for pretty
long to bring attention to what some might consider the root industry
precipitant/s.
-----

- gpsman

In article
>,
xyzzy > wrote:

> It may boggle the mind of a PP like you (or me for that matter) who
> seldom or never flies in icing conditions. However in icing
> conditions a tail stall is possible, and the recovery from that is
> exactly what this flight crew did. Yes, I know the Q400 is alleged
> not to be suspectible to this but the captain had just come from a
> type that is, and the FO spent a good part of the five minutes before
> the crash chatting about how she feared icing, had never experienced
> it before, and how would she handle it, etc. So then after chatting
> and worrying about icing, they got something that felt/looked like it
> could be an ice-induced tail stall and since it was on their minds
> they did the recovery from that. They acted on instinct and it was
> the wrong instinct. IMO.

Thanks for the input. However, there is something about what you say
which worries me greatly. You say that pulling back on the stick is the
correct response to a tail stall, the exact opposite of what you do for
a normal stall. Well, if you have a normal stall and react to it like a
tail stall, then you die, as evidenced by what happened here.

Do you also die if you react to a tail stall as though it were a normal
stall? Assuming the answer is "yes", how exactly are you supposed to
handle a situation where you don't know which is which?

You seem to be implying that the answer is "guess" (and please forgive
me if that's not what you meant to imply), which seems to be extremely
dangerous if you're basically flipping a coin to decide whether or not
you get to survive the stall.

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

On May 14, 5:53*pm, Mike Ash > wrote:
> In article
> >,
>
> *xyzzy > wrote:
> > It may boggle the mind of a PP like you (or me for that matter) who
> > seldom or never flies in icing conditions. *However in icing
> > conditions a tail stall is possible, and the recovery from that is
> > exactly what this flight crew did. Yes, I know *the Q400 is alleged
> > not to be suspectible to this but the captain had just come from a
> > type that is, and the FO spent a good part of the five minutes before
> > the crash chatting about how she feared icing, had never experienced
> > it before, and how would she handle it, etc. *So then after chatting
> > and worrying about icing, they got something that felt/looked like it
> > could be an ice-induced tail stall and since it was on their minds
> > they did the recovery from that. *They acted on instinct and it was
> > the wrong instinct. *IMO.
>
> Thanks for the input. However, there is something about what you say
> which worries me greatly. You say that pulling back on the stick is the
> correct response to a tail stall, the exact opposite of what you do for
> a normal stall. Well, if you have a normal stall and react to it like a
> tail stall, then you die, as evidenced by what happened here.
>
> Do you also die if you react to a tail stall as though it were a normal
> stall? Assuming the answer is "yes", how exactly are you supposed to
> handle a situation where you don't know which is which?
>
> You seem to be implying that the answer is "guess" (and please forgive
> me if that's not what you meant to imply), which seems to be extremely
> dangerous if you're basically flipping a coin to decide whether or not
> you get to survive the stall.

The way you recognize a tail stall is that pitch control becomes
abnormal when flaps are extended. Plus knowing that you're in icing
conditions.

Unfortunately that's what happened to the Q400, because coincidently
their airspeed decayed through wing stall speed at the same time flaps
were extended, so in this case they had a perfect storm to fool
themselves on the type of stall

Note, I'm not saying they were totally innocent here because they
aren't, as they should have been on top of their airspeed before it
happened, I'm just saying that internet PPL holders who never fly in
icing conditions have no right to say that "it boogles" the mind or is
inconceivable that the captain would "be so stupid" as to pull back on
the stick when he entered the stall.

In article <7a611b72-866e-4c6a-8dbb-
>, says...
> On May 14, 5:53*pm, Mike Ash > wrote:
> > In article
> > >,
> >
> > *xyzzy > wrote:
> > > It may boggle the mind of a PP like you (or me for that matter) who
> > > seldom or never flies in icing conditions. *However in icing
> > > conditions a tail stall is possible, and the recovery from that is
> > > exactly what this flight crew did. Yes, I know *the Q400 is alleged
> > > not to be suspectible to this but the captain had just come from a
> > > type that is, and the FO spent a good part of the five minutes before
> > > the crash chatting about how she feared icing, had never experienced
> > > it before, and how would she handle it, etc. *So then after chatting
> > > and worrying about icing, they got something that felt/looked like it
> > > could be an ice-induced tail stall and since it was on their minds
> > > they did the recovery from that. *They acted on instinct and it was
> > > the wrong instinct. *IMO.
> >
> > Thanks for the input. However, there is something about what you say
> > which worries me greatly. You say that pulling back on the stick is the
> > correct response to a tail stall, the exact opposite of what you do for
> > a normal stall. Well, if you have a normal stall and react to it like a
> > tail stall, then you die, as evidenced by what happened here.
> >
> > Do you also die if you react to a tail stall as though it were a normal
> > stall? Assuming the answer is "yes", how exactly are you supposed to
> > handle a situation where you don't know which is which?
> >
> > You seem to be implying that the answer is "guess" (and please forgive
> > me if that's not what you meant to imply), which seems to be extremely
> > dangerous if you're basically flipping a coin to decide whether or not
> > you get to survive the stall.
>
> The way you recognize a tail stall is that pitch control becomes
> abnormal when flaps are extended. Plus knowing that you're in icing
> conditions.
>
> Unfortunately that's what happened to the Q400, because coincidently
> their airspeed decayed through wing stall speed at the same time flaps
> were extended, so in this case they had a perfect storm to fool
> themselves on the type of stall
>
> Note, I'm not saying they were totally innocent here because they
> aren't, as they should have been on top of their airspeed before it
> happened, I'm just saying that internet PPL holders who never fly in
> icing conditions have no right to say that "it boogles" the mind or is
> inconceivable that the captain would "be so stupid" as to pull back on
> the stick when he entered the stall.

Well I think it's fair comment - there was no uncommanded pitch *down* -
(if that's what the pilot saw on instruments, then fair enough - but it
clearly isn't).

--
Duncan

In article
>,
xyzzy > wrote:

> The way you recognize a tail stall is that pitch control becomes
> abnormal when flaps are extended. Plus knowing that you're in icing
> conditions.

This still sounds like a total crapshoot to me. You can lose pitch
control during a regular stall, and icing can precipitate a regular
stall as well. Obviously in this case the signs were interpreted
incorrectly. Surely it's not a case of "heads we live, tails we die"?
There must be some way to tell which kind of stall is happening besides
these indications which clearly weren't correct in this case, isn't
there?

I guess there doesn't *have* to be, but it's kind of scary if there
isn't.

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

Mike Ash > wrote:

> xyzzy > wrote:
>
>> The way you recognize a tail stall is that pitch control becomes
>> abnormal when flaps are extended. Plus knowing that you're in icing
>> conditions.
>
> This still sounds like a total crapshoot to me. You can lose pitch
> control during a regular stall, and icing can precipitate a regular
> stall as well. Obviously in this case the signs were interpreted
> incorrectly. Surely it's not a case of "heads we live, tails we die"?
> There must be some way to tell which kind of stall is happening besides
> these indications which clearly weren't correct in this case, isn't
> there?
>
> I guess there doesn't *have* to be, but it's kind of scary if there
> isn't.

When the flaps are extended, and a tailplane stall results, the aircraft
immediately pitches down. There is no stall warning or stick shaker
activation.

In the case of the Buffalo accident, the nose did not drop, but the stick
shaker activated shortly after the flap setting was made. The stick
shaker is fired by low air speed, and is only a warning of impending wing
stall, with some airspeed margin. It is not an indication of tailplane
stall, or of an actual wing stall. Therefore, the correct action when
the stick shaker fired should have been to push the nose down to keep
speed up and reduce AOA. No question.

Further, the Q400 supposedly will never see a tailplane stall in icing,
but the crew may not have known that. The Saabs the captain previously
flew are subject to tailplane stall in icing, and he might have reacted
based on his previous training and apprehension about such stalls.

On May 15, 7:37*am, Mike Ash > wrote:
> In article
> >,
>
> *xyzzy > wrote:
> > The way you recognize a tail stall is that pitch control becomes
> > abnormal when flaps are extended. *Plus knowing that you're in icing
> > conditions.
>
> This still sounds like a total crapshoot to me. You can lose pitch
> control during a regular stall, and icing can precipitate a regular
> stall as well. Obviously in this case the signs were interpreted
> incorrectly. Surely it's not a case of "heads we live, tails we die"?
> There must be some way to tell which kind of stall is happening besides
> these indications which clearly weren't correct in this case, isn't
> there?
>
> I guess there doesn't *have* to be, but it's kind of scary if there
> isn't.

yes, another reason why it's best for guys like you and me to stay out
of icing conditions. You have to be pretty skilled and experienced
and know what you're doing, which is what we expect from ATP pilots.

As others have said, you can distinguish the difference if you really
know what you're doing, but better not to take that chance if you can
avoid it (which us PPL's, without the pressures of airline scheduling,
can do).

In article >,
James Robinson > wrote:

> When the flaps are extended, and a tailplane stall results, the aircraft
> immediately pitches down. There is no stall warning or stick shaker
> activation.
>
> In the case of the Buffalo accident, the nose did not drop, but the stick
> shaker activated shortly after the flap setting was made. The stick
> shaker is fired by low air speed, and is only a warning of impending wing
> stall, with some airspeed margin. It is not an indication of tailplane
> stall, or of an actual wing stall. Therefore, the correct action when
> the stick shaker fired should have been to push the nose down to keep
> speed up and reduce AOA. No question.
>
> Further, the Q400 supposedly will never see a tailplane stall in icing,
> but the crew may not have known that. The Saabs the captain previously
> flew are subject to tailplane stall in icing, and he might have reacted
> based on his previous training and apprehension about such stalls.

Ah hah, that makes sense. Given that the stick shaker had activated,
they should have known it was a regular stall and performed a regular
recovery. A tail stall would have happened abruptly with no stick
shaker. Is that about right? Makes sense if so.

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

On May 14, 8:12 am, James Robinson > wrote:

> There was a theory on one of the other pilot forums that the captain
> might have done all of his stall training when the aircraft was under
> manual control, untrimmed, with the throttles cut until the speed dropped
> below stall speed. He might have gotten used to having some backpressure
> on the control column to avoid altitude loss under those conditions.
>
> He might never have experienced stall training where the AP had ratcheted
> the pitch trim toward its maximum, and was caught by surprise with the
> sudden pitch up when the AP kicked off.
>
> The FDR shows his immediate reaction to the stick shaker was to apply 20
> lbs backpressure, which he immediately let go of as the aircraft pitched
> up. He never pushed on the control column, however the wild
> left/right/left/right rolls pretty well made controlling pitch a moot
> point.

Those rolls were made harder to get out of by the fact that the
captain let
the aircraft get all the way down to 80 kts at one point, and at such
low
airspeeds, the ailerons have much less effect, which he would have
known
if he had simply paid attention to his flight instructor.

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?

Perhaps, but even that doesn't make sense either. The airplane stall
warning system/ stick shaker was activating. This would only indicate a
stall condition is imminent for the wing. The stall warning system does
not indicate anything about the tail, so the only corrective measure to
take for a stick shaker would be a conventional wing stall recovery,
such as full available power, prop forward, pitch down, don't bring up
the flaps until a positive rate of climb is achieved.

I'm not familiar with the specific stall recovery for that type, but you
get the idea. If the pilot pushed the stick over to recover from a
non-existent tail stall, that was a bad move. I haven't seen anything
to suggest that happened however.

xyzzy wrote:
> On May 13, 2:14 pm, 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?
>
> It may boggle the mind of a PP like you (or me for that matter) who
> seldom or never flies in icing conditions. However in icing
> conditions a tail stall is possible, and the recovery from that is
> exactly what this flight crew did. Yes, I know the Q400 is alleged
> not to be suspectible to this but the captain had just come from a
> type that is, and the FO spent a good part of the five minutes before
> the crash chatting about how she feared icing, had never experienced
> it before, and how would she handle it, etc. So then after chatting
> and worrying about icing, they got something that felt/looked like it
> could be an ice-induced tail stall and since it was on their minds
> they did the recovery from that. They acted on instinct and it was
> the wrong instinct. IMO.

Perhaps that is exactly what happened. But their indication was the
stick shaker (aircraft stall warning system), which only indicates wing
stalls, not tail stalls. Regardless of type, the only correct response
to the stick shaker/stick pusher was to perform normal (wing) stall
recovery. Instinct should lower the nose immediately when the stick
starts shaking.

Mike Ash wrote:
> Ah hah, that makes sense. Given that the stick shaker had activated,
> they should have known it was a regular stall and performed a regular
> recovery. A tail stall would have happened abruptly with no stick
> shaker. Is that about right? Makes sense if so.

The thing though, at least according to the FAA video on tail stall thing
(it's on video.google.com, search for 'Tailplane Icing') it seems that
tail stall also manifests itself by odd pitch feedback on the yoke... I am
really wondering if there is any clear cut way to identify tailplane stall
from main wing stall as easily as you make it sound...

--Sylvain

"///" > wrote:

> On May 14, 8:12 am, James Robinson > wrote:
>
>> There was a theory on one of the other pilot forums that the captain
>> might have done all of his stall training when the aircraft was under
>> manual control, untrimmed, with the throttles cut until the speed
>> dropped below stall speed. He might have gotten used to having some
>> backpressure on the control column to avoid altitude loss under those
>> conditions.
>>
>> He might never have experienced stall training where the AP had
>> ratcheted the pitch trim toward its maximum, and was caught by
>> surprise with the sudden pitch up when the AP kicked off.
>>
>> The FDR shows his immediate reaction to the stick shaker was to apply
>> 20 lbs backpressure, which he immediately let go of as the aircraft
>> pitched up. He never pushed on the control column, however the wild
>> left/right/left/right rolls pretty well made controlling pitch a moot
>> point.
>
> Those rolls were made harder to get out of by the fact that the
> captain let the aircraft get all the way down to 80 kts at one point,
> and at such low airspeeds, the ailerons have much less effect, which
> he would have known if he had simply paid attention to his flight
> instructor.

They immediately dropped to 80 kts when the aircraft pitched up. Think
of a Russian Sukhoi fighter doing the cobra manoeuver. The low speed and
wild rolls meant the chances of recovery at that point were pretty slim.
The initial pull up, combined with the overcorrection to the rolls pretty
well made the accident inevitable.

Pushing the control column forward when they were rolled 100 degrees from
level wouldn't have done much to help.

Jessica > wrote:
>
> 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?
>
> Perhaps, but even that doesn't make sense either. The airplane stall
> warning system/ stick shaker was activating. This would only indicate
> a stall condition is imminent for the wing. The stall warning system
> does not indicate anything about the tail, so the only corrective
> measure to take for a stick shaker would be a conventional wing stall
> recovery, such as full available power, prop forward, pitch down,
> don't bring up the flaps until a positive rate of climb is achieved.

The question is what to do when everything happens at the same time?
That is, after the flap setting is increased, the stick shaker stall
warning fires, and the nose pitches down. What would you do then? The
stick shaker is only an indication of an impending stall, and there are
probably a few MPH margin left, but the increased flap setting might have
started a tailplane stall, on aircraft that have that tendency.

Immediately retracting the flaps might be the best course, along with
either level flight with increased power or slightly pushing the nose
down to keep the speed up. Pulling on the control column likely wouldn't
be a good idea, unless the pitch down was extreme. I don't know.

> I'm not familiar with the specific stall recovery for that type, but
> you get the idea. If the pilot pushed the stick over to recover from
> a non-existent tail stall, that was a bad move. I haven't seen
> anything to suggest that happened however.

The FDR shows moderate backpressure (20 lb, 40 lbs total) momentarily
applied to the control columns on both sides in response to the stick
shaker. This causes the aircraft to pitch up. When the aircraft pitches
up, the pressure is relaxed, to be reapplied by the left side when the
stick pusher is fired as the speed drops and the wing stalls.

Clearly, pulling on the control columns was the wrong thing to do, so why
did they both do it? Pushing should have been the instinctive reaction
to the stick shaker. I'm trying to figure out what else might have been
in their minds to generate the opposite reaction.

Mike Ash > wrote:
>
> James Robinson > wrote:
>
>> When the flaps are extended, and a tailplane stall results, the
>> aircraft immediately pitches down. There is no stall warning or
>> stick shaker activation.
>>
>> In the case of the Buffalo accident, the nose did not drop, but the
>> stick shaker activated shortly after the flap setting was made. The
>> stick shaker is fired by low air speed, and is only a warning of
>> impending wing stall, with some airspeed margin. It is not an
>> indication of tailplane stall, or of an actual wing stall.
>> Therefore, the correct action when the stick shaker fired should have
>> been to push the nose down to keep speed up and reduce AOA. No
>> question.
>>
>> Further, the Q400 supposedly will never see a tailplane stall in
>> icing, but the crew may not have known that. The Saabs the captain
>> previously flew are subject to tailplane stall in icing, and he might
>> have reacted based on his previous training and apprehension about
>> such stalls.
>
> Ah hah, that makes sense. Given that the stick shaker had activated,
> they should have known it was a regular stall and performed a regular
> recovery. A tail stall would have happened abruptly with no stick
> shaker. Is that about right? Makes sense if so.

The FDR data shows the following happening in quick sequence:

- Ice warning showing up on display for first time
- Flap handle setting increased
- Stick shaker activated

The flaps had only extended about 1 or 2 degrees when the stick shaker
fired, but was the crew somehow influenced by the ice warning and the
fact that the flaps setting had just been changed? They certainly took
the wrong action in response to the stick shaker. Why?

In article >,
Sylvain > wrote:

> Mike Ash wrote:
> > Ah hah, that makes sense. Given that the stick shaker had activated,
> > they should have known it was a regular stall and performed a regular
> > recovery. A tail stall would have happened abruptly with no stick
> > shaker. Is that about right? Makes sense if so.
>
> The thing though, at least according to the FAA video on tail stall thing
> (it's on video.google.com, search for 'Tailplane Icing') it seems that
> tail stall also manifests itself by odd pitch feedback on the yoke... I am
> really wondering if there is any clear cut way to identify tailplane stall
> from main wing stall as easily as you make it sound...

Well, I was just summarizing what I was replying to, to see if I had got
it correct.

In any case, it seems that, if there is not a clear-cut way to
distinguish between the two types of stalls, some way needs to be
created or else these aircraft are too dangerous. (Either that or it
needs to be made impossible to stall them at all.)

Maybe this is just my small aircraft experience misinforming me, and
stalls are rare enough that the potential for a screwup when they happen
is not something to be excessively worried about?

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

"Jessica" > wrote in message
...
> xyzzy wrote:
>> On May 13, 2:14 pm, 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?
>>
>> It may boggle the mind of a PP like you (or me for that matter) who
>> seldom or never flies in icing conditions. However in icing
>> conditions a tail stall is possible, and the recovery from that is
>> exactly what this flight crew did. Yes, I know the Q400 is alleged
>> not to be suspectible to this but the captain had just come from a
>> type that is, and the FO spent a good part of the five minutes before
>> the crash chatting about how she feared icing, had never experienced
>> it before, and how would she handle it, etc. So then after chatting
>> and worrying about icing, they got something that felt/looked like it
>> could be an ice-induced tail stall and since it was on their minds
>> they did the recovery from that. They acted on instinct and it was
>> the wrong instinct. IMO.
>
> Perhaps that is exactly what happened. But their indication was the stick
> shaker (aircraft stall warning system), which only indicates wing stalls,
> not tail stalls. Regardless of type, the only correct response to the
> stick shaker/stick pusher was to perform normal (wing) stall recovery.
> Instinct should lower the nose immediately when the stick starts shaking.

Maybe. But, if the Q400 has a stick pusher, then it could really confuse
the issue--take a look at the FAA/NASA video on tailplane icing at
http://video.google.com/videoplay?docid=2238323060735779946

Here is a link for considerable additional info, although it does appear to
include the FDR data which is linked elsewhere in this thread:
http://aircrewbuzz.com/2009/02/dash-8-crashes-on-approach-to-buffalo.html

We really don't know whether they actually had tailplane ice at the time,
not whether they did not, and we never will know because that sort of
evidence would not reasonably survive a crash.

Peter Dohm wrote:

> We really don't know whether they actually had tailplane ice at the time,
> not whether they did not, and we never will know because that sort of
> evidence would not reasonably survive a crash.

Knowledgeable people (as eg. NTSB's accident investigators) tend to read
a lot out of the FDR data. I'm pretty sure we *will* know when the final
accident report is released.

"Peter Dohm" > wrote:

> We really don't know whether they actually had tailplane ice at the
> time, not whether they did not, and we never will know because that
> sort of evidence would not reasonably survive a crash.

The manufacturer testified at the NTSB hearings that their certification
tests showed that the aircraft wasn't subject to tailplane stalls.

I'll wait for the NTSB results, but, if there's a silver lining to
this incident, it's that the major news networks must have been hit
with a few thousand e-mails pointing out pilot salary... In one
afternoon, CNN went from outrage over why such low-time pilots were
flying the airplanes to focusing on the fact that the pilots made less
than the average janitors. Somebody clued them in that you're not
going to get high-time superpilots flying your ass around if you
expect to pay them fast food drive-thru wages.

There's the bottom line that, fortunately, CNN tried to expose:
Americans are only going to get what they're willing to pay for and if
they want bargain-barrel rates they're going to have to expect bargain-
barrel service. Most people clearly still believe that air transport
pilots make doctor's wages. Maybe this will people up.



-c

On May 20, 2:00*pm, C Gattman > wrote:
> I'll wait for the NTSB results, but, if there's a silver lining to
> this incident, it's that the major news networks must have been hit
> with a few thousand e-mails pointing out pilot salary... *In one
> afternoon, CNN went from outrage over why such low-time pilots were
> flying the airplanes to focusing on the fact that the pilots made less
> than the average janitors. * Somebody clued them in that you're not
> going to get high-time superpilots flying your ass around if you
> expect to pay them fast food drive-thru wages.
>
> There's the bottom line that, fortunately, CNN tried to expose:
> Americans are only going to get what they're willing to pay for and if
> they want bargain-barrel rates they're going to have to expect bargain-
> barrel service. *Most people clearly still believe that air transport
> pilots make doctor's wages. *Maybe this will people up.
>
> -c

Well, that may be true, but the vultures are already circling and the
manufacturer and airline are going to be sued...

http://www.aero-news.net/index.cfm?ContentBlockID=c158dff3-38cb-42a0-bdc8-1ae3e0730f27&

wrote:
> Well, that may be true, but the vultures are already circling and the
> manufacturer and airline are going to be sued...
>
> http://www.aero-news.net/index.cfm?ContentBlockID=c158dff3-38cb-42a0-bd
> c8-1ae3e0730f27&

There are some interesting claims I heard directly from the attorney for
the respondent in the following case which was brought against a different
Colgan pilot in 2008:

http://www.ntsb.gov/alj/alj/o_n_o/docs/aviation/5421.pdf

The above just contains the judicial decisions and reasoning - very little
of the testimony is mentioned - and doesn't cover the nature of the FAA
response.

In the above case, basically the first officer of a Colgan flight accused
the captain of creating a false load manifest and thereby flying
recklessly. The captain and FO had personal animosities and the FO was
allegedly on his way to losing his job when the FO reported the incident.
According to the judge, the "resolution of this case rested on a
credibility determination." He found against the captain.

As I understand it, a list of unprofessional actions and flight activities
were brought to the attention of the FAA during this case, so the FAA
established a task force for the case. The attorney said he was expecting
the FAA task force to take action against Colgan back then - but nothing
happened. It would appear the FAA may have had ample warning of problems
with Colgan operations and just cause to order correction of deficiences,
but did nothing.

It would appear that in this case the FAA allowed its promotion of air
commerce to take precedence over its promotion of air safety, and a
specific and linear causal result was this crash.

On May 21, 5:37*pm, wrote:
> the vultures are already circling and the
> manufacturer and airline are going to be sued...

SOP is to sue everybody within a 150 mile radius.

An unnamed defendant may ultimately be found liable, and the
plaintiffs may find themselves ultimately screwed.

But... there's probably a real lawyer in here somewhere who might
expound on that.
-----

- gpsman

On 16 May, 13:25, James Robinson > wrote:
> Jessica > wrote:
>
> > 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?
>
> > Perhaps, but even that doesn't make sense either. *The airplane stall
> > warning system/ stick shaker was activating. *This would only indicate
> > a stall condition is imminent for the wing. *The stall warning system
> > does not indicate anything about the tail, so the only corrective
> > measure to take for a stick shaker would be a conventional wing stall
> > recovery, such as full available power, prop forward, pitch down,
> > don't bring up the flaps until a positive rate of climb is achieved.
>
> The question is what to do when everything happens at the same time? *
> That is, after the flap setting is increased, the stick shaker stall
> warning fires, and the nose pitches down. What would you do then? *The
> stick shaker is only an indication of an impending stall, and there are
> probably a few MPH margin left, but the increased flap setting might have
> started a tailplane stall, on aircraft that have that tendency.
>
> Immediately retracting the flaps might be the best course, along with
> either level flight with increased power or slightly pushing the nose
> down to keep the speed up. Pulling on the control column likely wouldn't
> be a good idea, unless the pitch down was extreme. I don't know.
>
> > I'm not familiar with the specific stall recovery for that type, but
> > you get the idea. *If the pilot pushed the stick over to recover from
> > a non-existent tail stall, that was a bad move. *I haven't seen
> > anything to suggest that happened however.
>
> The FDR shows moderate backpressure (20 lb, 40 lbs total) momentarily
> applied to the control columns on both sides in response to the stick
> shaker.

If memory serves me correctly, from my reading of NTSB material
the two control column force
transducers are *not* representative of the forces on the
two pilots' control columns.

There are two force sensors but I interpreted the explanation
to mean that it cannot be determined how much force each pilot
was applying.

http://www.ntsb.gov/Dockets/Aviation/DCA09MA027/417236.pdf
3.5.4. Control Column Forces
"With the system operating normally (for example,
disconnect not pulled), there is no way to determine
if pilot, copilot or both are flying."

There is more in the original doc. Quite complex and hard to
follow.

bod43 > wrote:

> James Robinson > wrote:
>
>> Jessica > wrote:
>>
>> > 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?
>>
>> > Perhaps, but even that doesn't make sense either. *The airplane
>> > stall warning system/ stick shaker was activating. *This would only
>> > indicate a stall condition is imminent for the wing. *The stall
>> > warning system does not indicate anything about the tail, so the
>> > only corrective measure to take for a stick shaker would be a
>> > conventional wing stall recovery, such as full available power,
>> > prop forward, pitch down, don't bring up the flaps until a positive
>> > rate of climb is achieved.
>>
>> The question is what to do when everything happens at the same time?
>> That is, after the flap setting is increased, the stick shaker
>> stall warning fires, and the nose pitches down. What would you do
>> then? *The stick shaker is only an indication of an impending stall,
>> and there are probably a few MPH margin left, but the increased flap
>> setting might have started a tailplane stall, on aircraft that have
>> that tendency.
>>
>> Immediately retracting the flaps might be the best course, along with
>> either level flight with increased power or slightly pushing the nose
>> down to keep the speed up. Pulling on the control column likely
>> wouldn't be a good idea, unless the pitch down was extreme. I don't
>> know.
>>
>> > I'm not familiar with the specific stall recovery for that type,
>> > but you get the idea. *If the pilot pushed the stick over to
>> > recover from a non-existent tail stall, that was a bad move. *I
>> > haven't seen anything to suggest that happened however.
>>
>> The FDR shows moderate backpressure (20 lb, 40 lbs total) momentarily
>> applied to the control columns on both sides in response to the stick
>> shaker.
>
> If memory serves me correctly, from my reading of NTSB material
> the two control column force
> transducers are *not* representative of the forces on the
> two pilots' control columns.
>
> There are two force sensors but I interpreted the explanation
> to mean that it cannot be determined how much force each pilot
> was applying.
>
> http://www.ntsb.gov/Dockets/Aviation/DCA09MA027/417236.pdf
> 3.5.4. Control Column Forces
> "With the system operating normally (for example,
> disconnect not pulled), there is no way to determine
> if pilot, copilot or both are flying."
>
> There is more in the original doc. Quite complex and hard to
> follow.

Thanks for pointing that out. I hadn't read it before, and it goes a
long way to explaining how the sensors work. It helps to read the
instructions.

You are correct that the system doesn't separate the forces on each
side, and the recorder only shows that somebody (or both) pulled back on
the control column(s) when the stick shaker intially fired. The pull
totaled about 40 lbs. A reasonable assumption is that the PF did the
deed alone.

The force applied by the PF relaxed as the aircraft pitched up, but when
the stick pusher activated, the backpressure on the column was reapplied,
even though the aircraft was pitched up by 30 degrees. The PF more or
less maintained the force against the stick pusher until impact.

Remember that while all of this is going on, the aircraft is wildly
rolling left and right.

On Sat, 16 May 2009 12:25:49 +0000 (UTC), James Robinson wrote:

> Clearly, pulling on the control columns was the wrong thing to do, so why
> did they both do it? Pushing should have been the instinctive reaction
> to the stick shaker. I'm trying to figure out what else might have been
> in their minds to generate the opposite reaction.

Sex?
--
Bear Bottoms
Private Attorney General

On May 21, 10:34*pm, gpsman > wrote:
> On May 21, 5:37*pm, wrote:
>
> > the vultures are already circling and the
> > manufacturer and airline are going to be sued...
>
> SOP is to sue everybody within a 150 mile radius.
>
> An unnamed defendant may ultimately be found liable, and the
> plaintiffs may find themselves ultimately screwed.
>
> But... there's probably a real lawyer in here somewhere who might
> expound on that.
> *-----
>
> - gpsman

Only if you pay him for his/her services... ;-)

BTW, never go to lunch with an attorney. You will get stuck with the
bill, and they will bill you for their time. True story.

wrote:
-c
>
> Well, that may be true, but the vultures are already circling and the
> manufacturer and airline are going to be sued...
>
> http://www.aero-news.net/index.cfm?ContentBlockID=c158dff3-38cb-42a0-bdc8-1ae3e0730f27&

That would happen if the pilot yelled "God is Great" and then pushed the
nose over.

wrote:
> 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.
But they were too low to lower trhe nose and in otrher words were fuc...

"PJ" > wrote in message
...
> wrote:
>> 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.
> But they were too low to lower trhe nose and in otrher words were fuc...


Google 'tail stall icing'
http://www.google.ca/search?hl=en&q=tail+stall+icing&btnG=Google+Search&meta=&aq=f&oq=

Happy landings,

PJ > 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.
>
> But they were too low to lower trhe nose and in otrher words were fuc...

First, the stick shaker is fired based on airspeed to give warning of an
impending stall. The aircraft is still several knots above stall speed
when it goes off. It hasn't yet stalled.

Second, they were at about 1600 ft AGL, meaning they had plenty of altitude
to recover, assuming the PF took the proper action. When he pulled up in
reaction to the stick shaker, the aircraft actually did stall, with the
nose up 30 degrees, and it rolled sharply to the left. At that point, they
were fuc...

"Private" > wrote:
>
> "PJ" > 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.
>>
>> But they were too low to lower trhe nose and in otrher words were
>> fuc...
>
> Google 'tail stall icing'
> http://www.google.ca/search?hl=en&q=tail+stall+icing&btnG=Google+Search&meta=&aq=f&oq=

According to the aircraft's manufacturer, the Dash8 isn't subject to
tailplane stalls due to icing. That said, one wonders if the pilot
had that in mind when he pulled up in reaction to the stick shaker.
His previous ride was a Saab, which I understand can stall due to
tailplane icing. Did the ice buildup he saw on the wings set his mind
up to prepare for a tailplane stall?