Buffalo Q400 crash

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).