Update on 3407

[tgrayson]

It's discussions along these lines that make "Stick and Rudder," simple and old as it is, still an important book to get that message across.

Full agreement. Read that as a student pilot and it really made everything click for me.

 

[Realms09]

That's not true at all. You can ALWAYS override lack of lift with thrust. A great example of this is the F-15. That thing can accelerate while climbing straight up, as in at a 90 degree angle. If your thrust output is greater than your weight, then you could in theory never "stall" the aircraft, because you'd ALWAYS have enough thrust to power out of whatever maneuver you were in.

The wing might not be flying, but that doesn't matter if you have enough thrust at your disposal.

To prevent confusion it is always good to be clear with terminology that is well defined. Given enough control authority you can most certainly stall an F-15 at full throttle. Airflow will separate over the wings, increasing drag coefficient and decreasing lift coefficient. Given enough thrust you can maintain level flight in the stalled condition, which is what you're saying. Unfortunately, even with enough thrust stalled wings are unstable. An increase in angle of attack causes a decrease in lift an increase in drag. In other words, you better be quick on those rudders because your crotch rocket will be all over the place. The only way to get a handle on it is a decrease in AoA.

 

[tgrayson]

If your thrust output is greater than your weight, then you could in theory never "stall" the aircraft,

You can stall any wing if your pitch rate exceeds the rate at which your flight path changes.

You can ALWAYS override lack of lift with thrust.

Depends on what you mean by that. There are two problems with a stall:

1) High drag, which enough thrust *can* overcome, and
2) Lack of control, which thrust cannot overcome.

EDIT: In other words, just what Realms09 said.

 

[gliderboy]

I'm surprised that only one poster mentioned what seemed to me a far more likely scenario.

1. Winter is on the way.

2. As part of training, the pilots watch the video on tailplane stalls (a very sobering video which leaves a lasting impression).

3. The pilot is flying in icing conditions, maybe he's a bit stressed because he doesn't have a lot of time in the plane, the video (and its admonishment to use the opposite control input from a wing stall) is fresh in his mind. The plane stalls and the pilot mistakenly assumes tailplane stall, ignores stick shaker/pusher and follows the training instruction to pull up hard for a tailplane stall.

Seems much more likely than incorrectly responding to a recognized imminent wing stall.

 

[Trip7]

Yeah what they said. Even in an overpowered plane like the 700 with no flex blasting off outta EYW, if you keep pitching up the speed will start to drop suddenly and if you got a trend vector it will shoot down the speedtape. Dont ask me how I know

Also, its great that everybody is getting educated on tailplane stalls, but I believe its getting some pilots confused. I think the most important fact that needs to be thought it tailplane vs. wing stall recognition. If the shaker goes off for goodness sakes please recognize a Wing Stall and do the proper recovery.

 

[kellwolf]

I also wanna toss something else out. The "power out" method of a stall in a jet works great for minimizing altitude loss.....at low altitudes. Try that at a high altitude, and the engines just don't have the excess thrust anymore to power out of the stall. Ask the guys on FLG3701. That's what got them into core lock.

 

[Minuteman]

If the shaker goes off for goodness sakes please recognize a Wing Stall and do the proper recovery.

On the Q400, is the shaker activated by a vane angle and not a calculated Stick Shaker Activation Speed?

 

[ppragman]

Yeah what they said. Even in an overpowered plane like the 700 with no flex blasting off outta EYW, if you keep pitching up the speed will start to drop suddenly and if you got a trend vector it will shoot down the speedtape. Dont ask me how I know

Also, its great that everybody is getting educated on tailplane stalls, but I believe its getting some pilots confused. I think the most important fact that needs to be thought it tailplane vs. wing stall recognition. If the shaker goes off for goodness sakes please recognize a Wing Stall and do the proper recovery.

Very very true.

That begs the question "are you going to get a stickshaker/stallwarninghorn if you get a tail stall? And the answer? Nope. (or at least theoretically you shouldn't because airflow over the wing is still good) you get a buffet in the tail and nose down pitch.

 

[TUCKnTRUCK]

On the Q400, is the shaker activated by a vane angle and not a calculated Stick Shaker Activation Speed?

Computed, based off AHARs data, air data, and AOA data, factored for configuration.

 

[Frequent Flier]

Before the stick shaker activated, what's the likely cause of 3407 slowing to 130 knots (as NTSB said the speed was at that point)?

The NTSB March 25 statement said the plane responded "as expected to flight control inputs throughout the accident flight" despite any icing.

Another Dash 8 flew a very similar path from Newark to Buffalo around 15 minutes later or so. If its stick shaker also activated that night, probably we'd have heard about that by now. So the other Dash 8 must have been going faster than 130 knots when it reached the same point.

If both Dash 8's were on A/P at that point in the flight (good bet, right? I think NTSB said last month 3407 was on A/P until shaker activated), and if both planes experienced very similar weather and flew close to the same path, what's to explain 3407 being significantly slower at that point near landing?

 

[TUCKnTRUCK]

The most probable cause is known by the NTSB, and none others. It would not be prudent to assume anything at this point.

There is no reason to assume the following Dash, or any of the other airplanes flying were on autopilot.

There is also No reason to assume they flew identical flight paths.

Unless you have access to privy information, why not wait for the NTSB like the rest of us?

*EDIT* sorry if i seem rude, but it certainly seems like your phishing for information, with a sign up date a day after the NTSB press release, asking questions that have pretty much been avoided all the way along - sets off reporter/laywer alarms.

If this isn't the case, welcome to the forums, and again, I'm sorry for blasting

 

[Frequent Flier]

Tuck,

I did say very similar paths, not identical paths. If I was mistaken that autopilot would be used on these kinds of flights, I'll stand corrected. The NTSB spokesman said A/P use is very common for this kind of aircraft and route. That's why I thought that.

Maybe my wording should've been different. Sorry if anything I wrote was out of place. I joined to be able to discuss. Lawyers would hire experts about these things and ask them directly, privately. No, I'm not a lawyer. I suppose the "why not wait?" question is fair and can be asked of many. Best answer I can think of is human nature. It's talked about everywhere you go here (I'm a few miles from the crash site), every day still. So many of us here lost people close, directly or indirectly.

(Btw, if my questions sound ignorant or inappropriate, you should hear some of the crazy things commonly say and ask publicly. I'm trying my best to be well informed and reasonable.)

Much focus in this discussion above was about what happened after the shaker started. Lots of opinions and ideas.

I thought my asking about prior to that point was constructively contributing - just a few minutes earlier in time. I'd think these topics are reasonable for open respectful inquiry among the whole flying community including passengers. If I'm mistaken, I'll stand corrected about that as well. I don't want to be an inappropriate guest here in any way.

Thanks for any feedback or insights.

 

[Seggy]

I think now would be an EXCELLENT time to post the press release on the alpa.org website

March 26, 2009


Irresponsible Journalism Interferes with NTSB Colgan Air 3407 Investigation

WASHINGTON – The Air Line Pilots Association, Int’l (ALPA), does not ordinarily comment publicly during any National Transportation Safety Board (NTSB) airline accident investigation to which the Association is a party. However, in response to several irresponsible news reports, including a story in USA Today, we feel that a public comment is not only necessary to balance the incorrect news stories, but it is also required to ensure that the investigative process is not interfered with or diverted.

“We urge the news media, and all who are affected by the Colgan Air Flight 3407 accident, to allow the investigation process to proceed without distraction from conjecture regarding the cause of the tragedy.
​

“On March 25, the National Transportation Safety Board (NTSB) released certain facts resulting from the investigation in the context of announcing the date for its public hearing on the accident. None of the facts were conclusive as to a cause, nor did the NTSB allude to a specific cause.

“As our industry has learned time and again, a rush to judgment with the intent to assign blame, rather than to advance safety, in an airline accident investigation fails to determine the action necessary to prevent a similar tragedy from happening again.

“The goal of accident investigation, and the legacy of all those who lost their lives in this accident, must be to create a safer airline industry. We urge all involved to join the Air Line Pilots Association, Int’l, in pursuing that goal.”
​

Founded in 1931, ALPA is the world’s largest pilots union, representing 52,250 pilots at 35 airlines in the United States and Canada.

 

[touch-n-go]

:yeahthat::yeahthat:

Thank You.

 

[BeechBoy]

I can't for the life of me understand why a pilot, when confronted with stick shaker and stall warning would pull up on the controls. As a CFI I tought and had it drilled into me, to push to recover from a stall. You must reduce the AOA.

Let me throw in my two cents. When we were doing stall training in the Dornier 328 at Skyway our main goal in stall training was to NOT LOSE ALTITUDE.

We would set it up flying level at 150 knots or so then power back and configure (if necessary). As the airplane slowed there was the usual tendency to pitch down which we would counter with trim. Per the procedure we weren't allowed to trim below 120 so we had only our muscles to maintain altitude.

By the time the airplane stalled at around 100 knots you were pulling back just about as hard as you could with one hand - it was a real handful. At the stall the procedure had you go to full power AND NOT LOSE ALTITUDE, which necessitated just about full back pressure on the yoke.

If you have a stall recovery procedure where, every time the stick shaker went off you were yanking back on the yoke as hard as you could AND CONTINUED TO DO SO AS PART OF THE RECOVERY PROCEDURE is there a chance that when the stick shaker went off for real that you would revert to the "muscle memory actions" that were drilled into you during training?

This is just a theory on my part that I'm throwing out there to get opinions on. I have no knowledge on what Colgan's stall recovery procedure was. I'm making the assumption :crazy: that it was similar to ours at Skyway.

 

[Cruise]

Let me throw in my two cents. When we were doing stall training in the Dornier 328 at Skyway our main goal in stall training was to NOT LOSE ALTITUDE.

We would set it up flying level at 150 knots or so then power back and configure (if necessary). As the airplane slowed there was the usual tendency to pitch down which we would counter with trim. Per the procedure we weren't allowed to trim below 120 so we had only our muscles to maintain altitude.

By the time the airplane stalled at around 100 knots you were pulling back just about as hard as you could with one hand - it was a real handful. At the stall the procedure had you go to full power AND NOT LOSE ALTITUDE, which necessitated just about full back pressure on the yoke.

If you have a stall recovery procedure where, every time the stick shaker went off you were yanking back on the yoke as hard as you could AND CONTINUED TO DO SO AS PART OF THE RECOVERY PROCEDURE is there a chance that when the stick shaker went off for real that you would revert to the "muscle memory actions" that were drilled into you during training?

This is just a theory on my part that I'm throwing out there to get opinions on. I have no knowledge on what Colgan's stall recovery procedure was. I'm making the assumption :crazy: that it was similar to ours at Skyway.

Your procedures for stall recovery are very similar to those at Colgan. We were always taught 'minimal loss of altitude.' Depending on the instructor, that could mean a couple hundred feet or less (read as 0). Also, you're absolutely correct with the muscle memory and the requirement to pull back on the control column to minimize altitude loss.

Recently, the stall recovery procedures have changed at Colgan.

 

[E_Dawg]

Two points

1. The shaker would not go off on a tail stall. Wings are still flying during a tail stall.

2. No matter what kind of power you have if you pitch up past the critical angle of attack the plane will stall. Impossible to power out of that. I believe I heard the plane pitched up to 31 degrees. Thats insane for even a jet.

If you increase AOA (not pitch) past the critical AOA, the plane will stall. Subtle but important distinction.

Not directed at you but:
A while back on another forum I read a comment by a regional pilot stating that he always climbed in Pitch mode, as opposed to Vertical Speed mode because Pitch mode eliminated the potential for the aircraft to stall.... a scary statement, and it leaves me wondering why don't the Feds focus more on things like THIS rather than the more typical job-justification BS like making sure my revision record is placed in the correct spot in my Jepp binder.

 

[OldTownPilot]

Recently, the stall recovery procedures have changed at Colgan.

I wonder if that will be a trend industry wide after 4701 and 3407. A change from 'minimal' to 'acceptable' altitude loss.

 

[kellwolf]

I wonder if that will be a trend industry wide after 4701 and 3407. A change from 'minimal' to 'acceptable' altitude loss.

They just nixed our stall profiles altogether. Now, it's a recovery technique akin to a TCAS RA or a windshear escape. Before it was a full on profile.

 

[zmiller4]

it leaves me wondering why don't the Feds focus more on things like THIS rather than the more typical job-justification BS like making sure my revision record is placed in the correct spot in my Jepp binder.

250hr FO's are OK, and you're good to go with 15:59 duty time and 8hrs rest, but god help you if you forgot to remove that 10-8 from the last revision.