Not so good news about flight 3407

[ultrarunner]

I was under the impression that the stall warning did not activate and the autopilot did not disconnect until the aircraft pitched up rapidly.

I'll have to go look at the report, but I believe the NTSB reported the AP was on until the stick shaker activated. A Q driver indicated this is system design.

Oddly enough, with all the press-releases the NTSB has been putting out in the media, they haven't bothered to even publish the preliminary report of the factual data yet.

 

[Andy Neill]

Ok, that makes sense-except if their actual stall speed was down around 100kts and the AOA sensor got adjusted to go off at closer to 120kts how did the wing actually stall?

If the stall speed was 90 and they saw 2 g's in a pull up, the stall speed jumps to 127 on a clean wing. SInce the flaps were in transit and the airspeed was slowing rapidly with the gear and flap extension, that was surely met.

 

[booo]

They are leaking this out slowly so that when it fully comes out it is not a bomb shell.

FWIW, it could be any of us, and if you think you are above it, you have not been aviation long enough.

I understand what you meant, but your statement should read:

......and if you think you are above it, you have been in aviation too long already.

 

[Stifler's Mom]

FWIW, it could be any of us, and if you think you are above it, you have not been aviation long enough.

My briefings incorporate your sentiments exactly. I am just as prone as the next guy to screw something up, so I expect you to speak up if you see something unusual.

 

[Oakum_Boy]

Indicated airspeed (IAS) is the airspeed read directly from the airspeed indicator on an aircraft, driven by the pitot-static system.

Calibrated airspeed (CAS) is the speed shown by a conventional airspeed indicator after correction for instrument error and position error.

Your J3 may read indicated airspeed. Modern airplanes read calibrated airspeed no matter what the indicator. Its part of the flight testing. You can check Part 25 and Part 23.

Uh, last time I checked, an air data computer driven airspeed indicator is not "conventional".

Manufactured in 2007 or 1927, you can't get CAS from a "conventional" airspeed indicator unless it's fed through a correction algorithm first. Only a computer can do that.

Your Wikipedia semantics are suspect. Try again.

 

[skiandsurf]

I was under the impression that the stall warning did not activate and the autopilot did not disconnect until the aircraft pitched up rapidly.

I dont think any of us know exactly what happened and in what order, but I do think...

...that the Q400 is a safe plane.
...fatigue was not a factor.
...and sadly, Pilot Error will be the final cause.

 

[akseiner]

It will come out that sterile cockpit, or rather lack of, was a large factor.

Impossible to say fatigue not a factor. Rebecca commuted in the night before on Fed ex.

I am really hoping for some twist to explain how a simple stall recovery went wrong.

 

[JustaNumber]

...and sadly, Pilot Error will be the final cause.

It is sad that pilot error is even still allowed to be labeled as the direct cause of an accident. It is well established that humans will always err, but our aviation system has evolved to a state of being able to trap most errors. The only way to prevent further accidents is to explore why the system failed to trap the error. This cannot be meaningfully done by simply closing the case with "pilot error" yet again.

 

[Oakum_Boy]

Anyone hearing about the latest warning about possible glideslope problems at BUF? Some talk on PPRUNE about it.

 

[MECH]

Safety Alert 2009-1
BUF ILS Hazard
​

Hazard to ILS to runway 23 in BUF
SWAPA Pilots,

There is a potentially significant hazard concerning the ILS to runway 23 in BUF.

Information has been received indicating it is possible to obtain a significant nose pitch up, in some cases as much as 30 degrees, if the glide slope is allowed to capture before established on centerline. Pilots who are preparing to configure and land have the potential to experience abrupt pitch up, slow airspeed, and approach to stall if conditions present themselves in a certain manner.

This effect is the result of an earthen obstruction close enough to the ILS to affect the integrity of the glide slope signal. This has resulted in the issuance of an advisory given on ATIS which states that "the ILS Glide Slope for runway 23 is unusable beyond 5 degrees right of course."
When attempting to intercept the runway 23 ILS from right traffic, the ILS glide slope indication may read full deflection down. Just prior to intercept it may then move up in such as manner as to enable approach mode to capture in such a way as to result in a nose up pitch and loss of airspeed.

Southwest Airlines has issued a notice reading: "Until further notice, when executing the KBUF ILS/LOC Runway 23, DO NOT select Approach Mode until established on the localizer inbound."
This issue is being addressed on several levels in an attempt to address procedures, facilities, and communication regarding this matter. If you experience any issues related to this, please file an ASAP form and or call SWAPA Safety at SWAPA toll free.

This could put a whole new slant to what happened.

 

[Oakum_Boy]

This could put a whole new slant to what happened.

You bet it could.

 

[belchfire]

Holy Crap Batman!

 

[q100]

Safety Alert 2009-1
BUF ILS Hazard
​

Hazard to ILS to runway 23 in BUF
SWAPA Pilots,

There is a potentially significant hazard concerning the ILS to runway 23 in BUF.

Information has been received indicating it is possible to obtain a significant nose pitch up, in some cases as much as 30 degrees, if the glide slope is allowed to capture before established on centerline. Pilots who are preparing to configure and land have the potential to experience abrupt pitch up, slow airspeed, and approach to stall if conditions present themselves in a certain manner.

This effect is the result of an earthen obstruction close enough to the ILS to affect the integrity of the glide slope signal. This has resulted in the issuance of an advisory given on ATIS which states that "the ILS Glide Slope for runway 23 is unusable beyond 5 degrees right of course."
When attempting to intercept the runway 23 ILS from right traffic, the ILS glide slope indication may read full deflection down. Just prior to intercept it may then move up in such as manner as to enable approach mode to capture in such a way as to result in a nose up pitch and loss of airspeed.

Southwest Airlines has issued a notice reading: "Until further notice, when executing the KBUF ILS/LOC Runway 23, DO NOT select Approach Mode until established on the localizer inbound."
This issue is being addressed on several levels in an attempt to address procedures, facilities, and communication regarding this matter. If you experience any issues related to this, please file an ASAP form and or call SWAPA Safety at SWAPA toll free.

This could put a whole new slant to what happened.

There are flight directors that will drive to a 30 degree pitch up?!?!?

Also, didn't 3407 intercept from the South, ie. left traffic? I don't remember from the ATC tapes, maybe someone out there can refresh my memory? Thx.

What a weird accident. Hope something good comes out of it all. Pretty depressing so far.

Q100.

 

[joe_pilot]

They are leaking this out slowly so that when it fully comes out it is not a bomb shell.

FWIW, it could be any of us, and if you think you are above it, you have not been aviation long enough.

The two most accurate sentences I've read on FI in a very long time. Of course the first is a guess, but I think it is spot on.

We need to really circle the wagons and support the families of the crew.

And learn.

-JP

 

[joe_pilot]

I understand what you meant, but your statement should read:

......and if you think you are above it, you have been in aviation too long already.

Good point, but the problem gets people at both ends and in the middle too.

 

[Crossky]

In reading the Q drivers explanation of how the AOA/Stall system is rescheduled in icing, the wing may not have actually aerodynamically stalled until it reached it's critical AOA during the abrupt pull-up maneuver.

There may not have actually been an aerodynamic stall when the pusher activated, since the pusher is biased by 20 knots as a function of being in icing conditions.

Put another way, with the 'icing switch' off, stall speed was shown to be computed at 90 kts or so.

. . .
Likely, as is typically the case, a combination. But it is clear the speed was allowed to decay to a very low value. After this, the abrupt pull-up sealed their fate at such a low altitude.

I agree with this scenario.

We'll know perhaps whether the crew was concerned about a tail stall from the CVR. They seemingly reacted to a perceived tail stall: extend flaps, the AP disconnects and they get shaker, then pusher. In a tail stall the nose drops, the remedy is to retract flaps and increase back pressure. Only thing is, they could've misinterpreted it. Stick shaker and pusher means WING STALL.

Fly the plane first, if the plane is still flying, don't mess with it. I got AP disconnect, shaker and pusher once with the boards out when new in the RJ on a visual. I had focused on descending after ALTS CAP to catch the GS, only a lower ALT hadn't been selected. I had increased thrust, but not enough to compensate for the drag from the flight spoilers. It took the jumpseater behind us to say 'spoilers' (yes this was humbling for me) before I clued in. But in that momemt before I got SA back I had increased thrust some, and done nothing to the pitch attitude.

Pilot error is sad, tragic, and unfortunately often a fact of life in aviation accidents. NBC didn't do regional pilots any favors tonight, explaining how long (short really) each had been employed by Colgan.

 

[joe_pilot]

There are flight directors that will drive to a 30 degree pitch up?!?!?

That was my first thought.

Also, didn't 3407 intercept from the South, ie. left traffic? I don't remember from the ATC tapes, maybe someone out there can refresh my memory? Thx.

Yup, from the south. Last assigned hdg was 260 to join

 

[joe_pilot]

I agree with this scenario.

We'll know perhaps whether the crew was concerned about a tail stall from the CVR. They seemingly reacted to a perceived tail stall: extend flaps, the AP disconnects and they get shaker, then pusher. In a tail stall the nose drops, the remedy is to retract flaps and increase back pressure. Only thing is, they could've misinterpreted it. Stick shaker and pusher means WING STALL.

Fly the plane first, if the plane is still flying, don't mess with it. I got AP disconnect, shaker and pusher once with the boards out when new in the RJ on a visual. I had focused on descending after ALTS CAP to catch the GS, only a lower ALT hadn't been selected. I had increased thrust, but not enough to compensate for the drag from the flight spoilers. It took the jumpseater behind us to say 'spoilers' (yes this was humbling for me) before I clued in. But in that momemt before I got SA back I had increased thrust some, and done nothing to the pitch attitude.

Pilot error is sad, tragic, and unfortunately often a fact of life in aviation accidents. NBC didn't do regional pilots any favors tonight, explaining how long (short really) each had been employed by Colgan.

Your candor about the brain-cramp is refreshing. We all need to work on this.

 

[skiandsurf]

It is sad that pilot error is even still allowed to be labeled as the direct cause of an accident. It is well established that humans will always err, but our aviation system has evolved to a state of being able to trap most errors. The only way to prevent further accidents is to explore why the system failed to trap the error. This cannot be meaningfully done by simply closing the case with "pilot error" yet again.

We, as pilots, will make mistakes. But its the severity of the mistakes that we can improve on. I always tell my flying partners that there are 2 types of mistakes: 1) one that we talk and laugh about and 2) one that others talk and laugh about. Lets keep them between the two of us.

 

[livin'thesim]

An operator of mid-sized turboprops had an interesting autopilot anomaly at a Michigan airport about a year or so ago.

Turned out to be the electronics playing tricks on the flight crew. I believe the actual flight control computer had a fault in it.

Maybe I'm just a little too crusty, but I feel that the automation has built a certain set of hazards into the system that we have yet to fully appreciate. And the automation seems to be expanding in new ways.

The biggest problem I have is that the box is often making many decisions that are not even documented in the manuals that pilots are issued.

There is often too much emphasis in 121 training on full reliance on automation. But think about TAWS. If you hear a terrain warning, you click off the AP and fly the escape maneuver. If you get a TCAS alert, you click off the AP and avoid the conflicting aircraft.

Why then, is it not safe to click off the AP in other instances where the pilot is behind the automation, or where the automation is behind the airplane?