Brazil Plane Crash

[Astro14]

I was wondering about how this would effect a Coanda wing like the one used on the C17 Globemaster III.

Not much, I imagine. I know a couple of guys who have flown it. It’s conventional in terms of handling, performance and aerodynamics.

Simply put, you don’t get out of a spin through thrust.

Wolfgang Langewiesche explained the spin phenomenon nearly a century ago in his wonderful book, “Stick and Rudder”. If you want to know how airplanes work, that is a great primer.

Basically, what happens is this - as AOA increases, you get more lift, and more induced drag up to the point of stall. That Angle of Attack at which the stall occurs is known as the critical angle of attack. It is important to note, that a wing will always stall at the same angle of attack. The airspeed and the load factor at that angle of attack may vary, so we’re going to ignore those for right now.

Induced drag by the way, is the drag on the wing that is caused by the creation of lift itself. We distinguish that from parasite drag, which is the simple drag caused by moving various parts of the airplane through the air. Parasite drag is proportional to the square of the velocity through the air, and for the moment, we are not going to consider things like altitude or density.

It is beyond the critical AOA, beyond the point of stall, that things get interesting.

In that region of flight, an increase in AOA causes less lift and more drag. Keep this in mind.

In order to enter a spin, you must stall the aircraft and you must then induce a yaw. That yaw can come from a thrust asymmetry, but it typically comes from uncoordinated Flight, or the misapplication of rudder, and it can also come from aileron input during the stall.

You can stall an airplane straight ahead without yaw and it will simply stall. A spin requires both a stall and yaw.

Once the yaw starts, the spin becomes self perpetuating. The forward moving wing has a lower angle of attack, and therefore more lift, and less drag, (see the note above on how things work above the critical AOA) so it continues to move forward. The rearward moving wing, has a higher angle of attack, and therefore less lift, and more drag. So the airplane continues to yaw in the direction of the spin because of those forces.

If the aircraft were below the critical angle of attack at the moment this yaw was input, then the forces for the spin would never develop. The forward moving wing would have a slightly lower angle of attack, but it would have more drag and more lift, while the rearward moving wing would have less drag and less lift, which would tend to stabilize the airplane in yaw.

Again, both a stall AOA and yaw are required for a spin.

Depending on the design of the airplane, and various parameters like the center of gravity and others, some airplanes will spin fairly nose low, and some will spin in a fairly nose level attitude. It just varies. For description of the true flat spin, I encourage you to go back and look through my F-14 thread. That airplane spun with a flat attitude. Its decent rate during the spin was approximately 30,000 feet per minute. The pilot experienced approximately six Gs towards the nose of the aircraft, rendering him unable to move, if he had not locked his harness prior to spin entry.

Now some airplanes are easier to get into a spin and some airplanes are easier to get out. But the bottom line is that you have to break the angle of attack, as well as stop the rotation, so most airplanes recover when rudder is applied and the yoke/stick pushed forward. Depending on the aircraft design, recovery may take a couple of turns, or it may be nearly instant. It depends and I’ve spun airplanes that fall into both categories.

Part of the reason that recovery is so difficult, is that when the airplane is falling out of the sky in a spin, the pilots instinct is to pull back on the flight controls, this increases AOA and makes things worse. Further, applying aileron input above critical AOA, on an airplane with ailerons, against the spin increases the yaw and drag effects noted above, and makes things worse.

There is already air moving over the wings and the control surfaces during this entire event. Applying power may just make things worse, particularly in a propeller driven aircraft that has what is known as “P – factor” in which application of power induces a yaw.

An intentional spin is usually a prohibited maneuver in a transport category airplane. Recovering from a spin in a big airliner, requires that you never get into it in the first place. The first indication of the stall, you must control the AOA, and push forward on the yoke/stick.

Applying full power in an aircraft like a 737, where the thrust axis is below the wing, tends to push the nose up, therefore increasing the stall, and making the spin worse.

Recovering from the spin requires managing the AOA, then managing the yaw, but it does not require power, and power can, in fact, exacerbate the problem.

So, back to this particular incident. Icing or not, mechanical problem, or not, the failure to manage AOA is the reason that they entered the spin. I don’t care what you’re doing, as a pilot, the absolute first priority is to fly the aircraft, to manage the flight path of that aircraft, and that includes all of the parameters such as heading, altitude, airspeed, but especially AOA.

Management of that flight path must come first above all other priorities, including combating an engine fire or failure, talking on the radio, or anything else.

Managing the flight controls, and the path of the aircraft must have absolute primacy.

 

[wpod]

Not much, I imagine. I know a couple of guys who have flown it. It’s conventional in terms of handling, performance and aerodynamics.

Simply put, you don’t get out of a spin through thrust.

Wolfgang Langewiesche explained the spin phenomenon nearly a century ago in his wonderful book, “Stick and Rudder”. If you want to know how airplanes work, that is a great primer.

Basically, what happens is this - as AOA increases, you get more lift, and more induced drag up to the point of stall. That Angle of Attack at which the stall occurs is known as the critical angle of attack. It is important to note, that a wing will always stall at the same angle of attack. The airspeed and the load factor at that angle of attack may vary, so we’re going to ignore those for right now.

Induced drag by the way, is the drag on the wing that is caused by the creation of lift itself. We distinguish that from parasite drag, which is the simple drag caused by moving various parts of the airplane through the air. Parasite drag is proportional to the square of the velocity through the air, and for the moment, we are not going to consider things like altitude or density.

It is beyond the critical AOA, beyond the point of stall, that things get interesting.

In that region of flight, an increase in AOA causes less lift and more drag. Keep this in mind.

In order to enter a spin, you must stall the aircraft and you must then induce a yaw. That yaw can come from a thrust asymmetry, but it typically comes from uncoordinated Flight, or the misapplication of rudder, and it can also come from aileron input during the stall.

You can stall an airplane straight ahead without yaw and it will simply stall. A spin requires both a stall and yaw.

Once the yaw starts, the spin becomes self perpetuating. The forward moving wing has a lower angle of attack, and therefore more lift, and less drag, (see the note above on how things work above the critical AOA) so it continues to move forward. The rearward moving wing, has a higher angle of attack, and therefore less lift, and more drag. So the airplane continues to yaw in the direction of the spin because of those forces.

If the aircraft were below the critical angle of attack at the moment this yaw was input, then the forces for the spin would never develop. The forward moving wing would have a slightly lower angle of attack, but it would have more drag and more lift, while the rearward moving wing would have less drag and less lift, which would tend to stabilize the airplane in yaw.

Again, both a stall AOA and yaw are required for a spin.

Depending on the design of the airplane, and various parameters like the center of gravity and others, some airplanes will spin fairly nose low, and some will spin in a fairly nose level attitude. It just varies. For description of the true flat spin, I encourage you to go back and look through my F-14 thread. That airplane spun with a flat attitude. Its decent rate during the spin was approximately 30,000 feet per minute. The pilot experienced approximately six Gs towards the nose of the aircraft, rendering him unable to move, if he had not locked his harness prior to spin entry.

Now some airplanes are easier to get into a spin and some airplanes are easier to get out. But the bottom line is that you have to break the angle of attack, as well as stop the rotation, so most airplanes recover when rudder is applied and the yoke/stick pushed forward. Depending on the aircraft design, recovery may take a couple of turns, or it may be nearly instant. It depends and I’ve spun airplanes that fall into both categories.

Part of the reason that recovery is so difficult, is that when the airplane is falling out of the sky in a spin, the pilots instinct is to pull back on the flight controls, this increases AOA and makes things worse. Further, applying aileron input above critical AOA, on an airplane with ailerons, against the spin increases the yaw and drag effects noted above, and makes things worse.

There is already air moving over the wings and the control surfaces during this entire event. Applying power may just make things worse, particularly in a propeller driven aircraft that has what is known as “P – factor” in which application of power induces a yaw.

An intentional spin is usually a prohibited maneuver in a transport category airplane. Recovering from a spin in a big airliner, requires that you never get into it in the first place. The first indication of the stall, you must control the AOA, and push forward on the yoke/stick.

Applying full power in an aircraft like a 737, where the thrust axis is below the wing, tends to push the nose up, therefore increasing the stall, and making the spin worse.

Recovering from the spin requires managing the AOA, then managing the yaw, but it does not require power, and power can, in fact, exacerbate the problem.

So, back to this particular incident. Icing or not, mechanical problem, or not, the failure to manage AOA is the reason that they entered the spin. I don’t care what you’re doing, as a pilot, the absolute first priority is to fly the aircraft, to manage the flight path of that aircraft, and that includes all of the parameters such as heading, altitude, airspeed, but especially AOA.

Management of that flight path must come first above all other priorities, including combating an engine fire or failure, talking on the radio, or anything else.

Managing the flight controls, and the path of the aircraft must have absolute primacy.

Back in 1978 and 1979 one of the Guys I used to work with wanted to become an airline pilot and he gave flying lessons to build up his loggable hours, when ever he had an opening I would go for an introductory lesson [ many ] which was a discounted plane rental and he wouldn't charge his labor rate. I got to steer the plane and we did mostly stall and stall recovery , that was what he thought was most important. It was fun .

 

[Just a civilian pilot]

I was wondering about how this would effect a Coanda wing like the one used on the C17 Globemaster III.

Just back from flying all day.

Astro answered it well.

 

[IndyFan]

I don't have many hours, but I did do spin training in a Piper Tomahawk when I was 16 years old. The first two spins took a lot of altitude for me to recover...in fact, the first one got me so dizzy and disoriented that the instructor took control and recovered the airplane. I recovered on the second spin, but lost a lot of altitude and wound up sick again with nausea. The third was the charm. I recovered pretty quickly. I d several more and became pretty adept at recovering without too much loss in altitude.

Spin training, obviously, was optional. I did it because I never wanted to get into that situation and not know or have a feel for what to do. Like the video of the Beech twin, the Tomahawk felt like it flipped over inverted right after the stall and upon entry into the spin. It scared the **** out of me the first time. I can imagine that many an aircraft has been lost to spins that could have been recoverable had the pilots had training.

I'm not implying that the pilots could have saved this ATR. I'm just pointing out that a spin can be very scary and quickly disorienting in a way that can make what is really a recoverable spin into a fatal tragedy.

I'm glad I did the spin training, but glad I never had to use it outside of training with a very good and skilled instructor. It actually was fun at or around the third or fourth try. But it sure wouldn't be fun if it unexpectedly occurred.

 

[wwillson]

I don't have many hours, but I did do spin training in a Piper Tomahawk when I was 16 years old. The first two spins took a lot of altitude for me to recover...in fact, the first one got me so dizzy and disoriented that the instructor took control and recovered the airplane. I recovered on the second spin, but lost a lot of altitude and wound up sick again with nausea. The third was the charm. I recovered pretty quickly. I d several more and became pretty adept at recovering without too much loss in altitude.

Spin training, obviously, was optional. I did it because I never wanted to get into that situation and not know or have a feel for what to do. Like the video of the Beech twin, the Tomahawk felt like it flipped over inverted right after the stall and upon entry into the spin. It scared the **** out of me the first time. I can imagine that many an aircraft has been lost to spins that could have been recoverable had the pilots had training.

I'm not implying that the pilots could have saved this ATR. I'm just pointing out that a spin can be very scary and quickly disorienting in a way that can make what is really a recoverable spin into a fatal tragedy.

I'm glad I did the spin training, but glad I never had to use it outside of training with a very good and skilled instructor. It actually was fun at or around the third or fourth try. But it sure wouldn't be fun if it unexpectedly occurred.

I did my primary training in a Tomahawk. We didn't spin it, but of course did a lot of stall recovery. The Tomahawk was designed to be stall recovery neutral, meaning when you stall it you have to go through the proper procedure to recover from the stall. It won't recover if you just let go of the controls. Other airplanes I've flown are designed to have self recovery characteristics and will begin a recovery if you just take your hands off the controls. Some people like the Tomahawk, some people don't. I thought it was a really nice flying trainer and yeah, it really made you recover from stalls correctly. I don't see anything wrong with that. On a sour note, the Tomahawk is the most under powered airplane I've ever flown.

 

[Astro14]

Let me add one other point to the spin discussion.

The Airspeed indicator information on most airplanes is derived from a pitot tube that faces forward.

At a high angle of attack, or in a spin, the airspeed can read zero, because there is little air coming towards the nose, and into that tube, but there is still flow over the surfaces of the airplane.

Even approaching zero indicated airspeed, you can still fly most airplanes - you won’t be climbing, or turning, but you still have some control with which to regain enough airspeed to fly.

If you have enough altitude and/or power to do so

 

[Just a civilian pilot]

The Aviation Herald reports that this same ATR 72 had a serious tail strike previously that caused substantial damage given how long it was grounded this year.

On the subject of no airspeed.....AF 447 had no IAS when it was in a deep stall coming down like a rock but they never took corrective action to get out of it. Airbus says it would have been too late anyways considering it was coming down at over 10,000 per minute and so out of trim.

 

[edyvw]

The Aviation Herald reports that this same ATR 72 had a serious tail strike previously that caused substantial damage given how long it was grounded this year.

On the subject of no airspeed.....AF 447 had no IAS when it was in a deep stall coming down like a rock but they never took corrective action to get out of it. Airbus says it would have been too late anyways considering it was coming down at over 10,000 per minute and so out of trim.

I was about to add this. That tailstrike will definitely be the focus of the investigation.

 

[IndyFan]

I did my primary training in a Tomahawk. We didn't spin it, but of course did a lot of stall recovery. The Tomahawk was designed to be stall recovery neutral, meaning when you stall it you have to go through the proper procedure to recover from the stall. It won't recover if you just let go of the controls. Other airplanes I've flown are designed to have self recovery characteristics and will begin a recovery if you just take your hands off the controls. Some people like the Tomahawk, some people don't. I thought it was a really nice flying trainer and yeah, it really made you recover from stalls correctly. I don't see anything wrong with that. On a sour note, the Tomahawk is the most under powered airplane I've ever flown.

I loved it, and you are right. Way underpowered. I loved the almost bubble canopy and visibility and it had tons of room for a tall guy with long legs. I remember seeing a 150hp (IIRC) conversion. That would have been a nice upgrade.

I felt it was a great trainer because of what you describe. You had to learn to feel the airplane, and you absolutely could. It could take a beating, too. One of the Tomahawks at the FBO was a Tomahawk II with the larger wheels. I had the fun of landing it many times on grass runways, some of which were pretty bumpy. Loved every minute of it.

If you stalled it more abruptly, man that left wing would take a real dive, again like that Beech in the video. That got your attention!

I wonder if the Beech Skipper, which was a very similar design, had more horsepower or if it was the same? I never flew one, but they looked just like the Tomahawk.

Also, is the Cessna 150 spin rated for training? I think I remember it not, except for maybe the Aerobat.

I can't help but wonder if that ATR spin would have been recoverable if the crew had the skill and/or experience? I'm sure in time we'll find out.

 

[wwillson]

Also, is the Cessna 150 spin rated for training? I think I remember it not, except for maybe the Aerobat.

The Cessna 150 initially was approved for intentional spins, however the FAA issued an AD that either part of the tail had to be replace with strengthened components or the airplane had to be placarded against intentional spins.

Every 150 I flew was certified for intentional spins and I intentionally spun them many times. Great fun.

 

[Astro14]

The key to avoiding a spin in an airliner is to recognize the stall and recover immediately. You have to stall first in order to spin, and there are plenty of warnings about stall in any airliner.

But the training of the crew, and their performance under the pressure of actual, IMC flight with a stall must be examined.

Colgan Air 3407 provides an example of improper crew response.

 

[IndyFan]

I did my primary training in a Tomahawk. We didn't spin it, but of course did a lot of stall recovery. The Tomahawk was designed to be stall recovery neutral, meaning when you stall it you have to go through the proper procedure to recover from the stall. It won't recover if you just let go of the controls. Other airplanes I've flown are designed to have self recovery characteristics and will begin a recovery if you just take your hands off the controls. Some people like the Tomahawk, some people don't. I thought it was a really nice flying trainer and yeah, it really made you recover from stalls correctly. I don't see anything wrong with that. On a sour note, the Tomahawk is the most under powered airplane I've ever flown.

Here ya go!

 

[Just a civilian pilot]

Since severe "icing" reports have been mentioned in the ATR 72 crash, I just want to make it 100% clear that AF 447 did NOT encounter severe icing, it flew into ice crystals at high altitude ( low moisture at high altitude ) which froze over the pitot tubes ( faulty anti ice system ) and confused the pilots once the auto pilot and auto thrust disconnected ( aircraft is designed so that if the 7 flight control computers cannot understand what's going on, it hands over control to the pilots to fly and figure out ) due to unreliable airspeed problems that the crew failed to identify and call for the unreliable airspeed checklist ( as advanced as the Airbus is, flight computers won't always tell pilots that there is a problem with unreliable airspeed and the pilots better figure it out ).

Because the aircraft was now in alternate law because of the failure( degraded mode ), the aircraft was a lot more sensitive to flight control inputs which led to the pilot over controlling which is dangerous at high altitude due to a much smaller performance envelope.

The aircraft entered a stall but the crew failed to recognize ( its in the report as bizarre as it sounds ) the buffetting and stall warning because they never once ( they applied TOGA thrust later, that's it ) applied the recovery technique.

Previous aircraft along the same route diverted around the weather but AF 447 only deviated 12 degrees according to the report.

Just wanted to clear up some inaccurate information on that accident relating to "severe ice".

 

[wwillson]

The key to avoiding a spin in an airliner is to recognize the stall and recover immediately. You have to stall first in order to spin, and there are plenty of warnings about stall in any airliner.

The aircraft entered a stall but the crew failed to recognize ( its in the report as bizarre as it sounds ) the buffeting and stall warning because they never once ( they applied TOGA thrust later, that's it ) applied the recovery technique.

When @Astro14 and I stalled the 757-200 multiple times, I was surprised at a couple things.

First, the 757 has very good aileron authority even when stalled. Some small airplanes I've flown, like the Piper Malibu, has almost zero aileron authority when stalled. The Malibu wants to roll over on it's back and it does so with almost no warning. The 757 when stalled will shake the fillings out of your teeth, but it doesn't roll, this is most impressive. @Astro14 will the 757 or 767 spin of you kick the rudder in a stall?

Second, like with the AF 447, we stalled the 757 and held it in a deep stall, then applied full power. The wing makes so much induced drag that even the 757 does not have enough thrust to overcome the drag. If you maintained the stall by holding full back elevator even with full power, you would be in a stall all the way to the ground just like AF 447. It still astonishes me that the two pilots of AF 447 didn't recognize one of the most fundamental aspects of flying any airplane, a stall.

 

[Astro14]

When @Astro14 and I stalled the 757-200 multiple times, I was surprised at a couple things.

First, the 757 has very good aileron authority even when stalled. Some small airplanes I've flown, like the Piper Malibu, has almost zero aileron authority when stalled. The Malibu wants to roll over on it's back and it does so with almost no warning. The 757 when stalled will shake the fillings out of your teeth, but it doesn't roll, this is most impressive. @Astro14 will the 757 or 767 spin of you kick the rudder in a stall?

Second, like with the AF 447, we stalled the 757 and held it in a deep stall, then applied full power. The wing makes so much induced drag that even the 757 does not have enough thrust to overcome the drag. If you maintained the stall by holding full back elevator even with full power, you would be in a stall all the way to the ground just like AF 447. It still astonishes me that the two pilots of AF 447 didn't recognize one of the most fundamental aspects of flying any airplane, a stall.

So, a couple of thoughts and comments on all this.

First, the 757 has one of the best thrust to weight ratios of any airliner ever built. That’s part of why I like flying it so much. It is a hot rod airplane. So, when Wayne tells you that you can’t power out of a stall, that is absolutely true. When I say “drag increases” beyond critical AOA, it’s not by a few percent. It is a huge change and it is enough drag to overcome the thrust being put out by those two RB211 engines, which combined, are about 85,000# of thrust.

So, even the 757 will not power out of a stall, much less a spin, using thrust. It absolutely has to be flown, using primary flight controls. Direct answer to Wayne’s question, I am not sure if you can spin it. This gets into a discussion of the accuracy of the aerodynamic model included in the simulator. Boeing doesn’t go out and intentionally spin large airliners. Nobody does. So there are some regions of the Flight envelope model in the simulator that are simply extrapolations of what happens at slightly lower AOA and lower yaw.

It can be dangerous, therefore, to draw any conclusions about how the actual airplane will handle in an extreme situation from the simulator, and how it presents those extreme situations. You want to be very careful about predicating your understanding, much less procedures, on an extrapolation. This was one of the issues that led up to the crash of American 587.

From their experience in the Airbus A300 simulator, the FO developed some odd habits about rudder input. In fact, the whole “advanced maneuvering“ program at American Airlines was based largely on simulator extrapolation. They were not the only airline guilty of basing their procedures for recovering from an upset on how the simulator flew, with without really being certain that that’s how the aircraft would fly.

On that morning, when American 587 was caught in the wake turbulence of a departing Japan airlines 747, the first officer applied full rudder left then right then left. Sequential, opposite, inputs. Inputs that only made sense if you were maneuvering in an extreme situation, and while encountering the wake vortex of a 747 can be pretty violent, aileron is the proper control to keep your wings level, not stomping on the rudder.

That violent, sequential, opposite rudder input exceeded the design load of the aircraft structure, and he snapped the tail off. The loss of control happened a few seconds later, and we all know the result.

So, to circle back to Wayne‘s question, don’t know if you could spin a 757, I suspect you can, and I suspect you can recover, but that is all based on the simulator aerodynamic model, which is an extrapolation. So it remains a big “maybe”.

Second, the 757, like the 767, the 747, and the Airbus 320, and I suspect nearly every other airliner, has a pretty strong degree of “aerodynamic twist“ by that, I mean that the mean chord line changes from higher at the wing root to lower at the wing tip. That means that fundamentally the wing root of the aircraft is flying at a higher angle of attack than the outer part of the wing.

So, when you stall an airliner, it stalls at the wing root. This is by design. It is designed to give you good aileron control even after you exceed stall angle of attack. The airplane is sluggish in roll, but it does not experience the adverse yaw, or the opposite direction departure of controlled flight exhibited by various fighter and attack aircraft I have flown, or that are exhibited by the aircraft in Wayne’s experience.

Finally, it’s really important to understand what was going on in the mind of the pilots on Air France 447.

The first officer, who was at the controls, was pretty inexperienced.

The way the airbus displays a change in flight control law, which is to say the logic by which pilot and computers move the control surfaces, is pretty small, and it may or may not have been noticed when other things are going on.

When you learn to fly the airbus, it’s really cool how good the flight control system is.

Windshear recovery?

Apply maximum thrust and hold the stick full aft. The flight control system brings the aircraft optimum AOA, which is just slightly below critical AOA, and you get maximum performance.

Stall recovery?

Apply maximum thrust and hold the stick full aft. The flight control system brings the aircraft optimum AOA, which is just slightly below critical AOA, and you get maximum performance.

Encounter with terrain? GPWS warning?

Apply maximum thrust and hold the stick full aft. The flight control system brings the aircraft optimum AOA, which is just slightly below critical AOA, and you get maximum performance.

See the pattern, here? Max thrust and fullback stick is how you were trained when the airplane gets in extremis…

But you have to have working flight control envelope protection - that is, the aircraft has to be and what is known as “normal law”. When data input to the flight control system are degraded, as was the case when that probe stopped, the aircraft is designed to revert back to what’s called “alternate law”. In which full authority is given back to the pilots. It means the computers can’t figure out what’s going on, so better to give full control to the pilots.

And here’s the problem, First, the FO was inordinately concerned about icing and trying to climb. He tried to climb to the absolute maximum altitude of which the aircraft was capable. This doesn’t give you a lot of margin for error, you’re very close to maximum speed and you’re very close to stalling at the same time. The FO put the airplane in a flight regime that didn’t leave them a whole lot of room for error.

The first indication of a problem was an over speed warning. This was a faulty warning, but that put the airplane back in alternate law. The FO picked up the nose in order to decelerate the airplane. Common sense would tell you that if you’re already flying at the maximum altitude, picking the nose up is a bad idea. But it was late at night, and we cannot not underestimate the effect of an amygdala hijack.

https://www.medicalnewstoday.com/articles/amygdala-hijack

When your fight or flight instinct kicks in, in response to a startling event, you lose frontal lobe function, focus on the threat, exclude audio, increase breathing, heart rate and adrenaline, and a host of other physiological responses that are great if you’re about to fight a saber tooth tiger but absolutely terrible in a complex, technical environment in which analysis and thinking are required.

I promise Amygdala Hijack was a factor in this crash as well - that’s very likely why they ended up in a spin.

Back to AF 447 - when they didn’t understand the situation, the startle response kicked in. It was said at least a dozen times on the tape, by all the members of the crew “what is happening!??”. So, when under stress, you tend to revert to training, and what was the training?

Yep - Max thrust and full back stick.

Except when the airplane is in alternate law, you get a tremendous deep stall. As you hold full back, the horizontal stabilizer continues to trim nose up, making this even worse.

Once they hit 10,000 feet, with the airplane down around 100 kn, full thrust on the engines in the elevator trimmed full nose up, there was no longer a chance of recovery. They needed 30 seconds of full forward, stick to re-trim the elevator, and they needed to break that angle of attack, and the thrust of the engines, which caused the nose to pitch up, wasn’t really helping. They were doomed at that point.

The question, for those who have never flown, and never felt a startle where your life depends on the things that you do in the next few seconds, why didn’t they recognize the stall? They didn’t because the amygdala hijack dumped enough adrenaline that their frontal cortex wasn’t fully engaged. The FO didn’t recognize why the overspeed happened, he didn’t understand the buffet initially, because he thought it was still the overspeed when, in fact, it was a stall. So, if you’re going to recognize that your initial assessment of the situation was incorrect, you’re gonna need all of your faculties, and on that dark night, because of human physiology, they didn’t have all of those faculties available.

All because bad sensor data caused the aircraft to give full control back to the pilots.

 

[Astro14]

Let me add that I had a similar pitot-static system failure one night flying off of a carrier, through thunderstorms.

We were doing about 350 knots. All of a sudden, my airspeed, and my backseat/RIO airspeed, indicators went to zero.

I think my exact words at the time were “huh, that’s weird - hey, Ferris, what do you have for airspeed?” “Zero”. “Well that can’t be right, we’re were flying a second ago, and I didn’t change pitch or power, must be a bad indicator.” “yeah, did you go over-ride on the anti-ice?” “Not yet, let me do that”. Our altitude and attitude remained steady, and in fact, our ground speed as read out from the INS was steady.

What seemed like a long time later, we flew out of the clouds.

A few seconds after that the airspeed indicator began indicating normally.

Yep.

We were still flying.

The difference is the amygdala hijack, the degree to which I allowed the startle response to affect my actions and my thinking, and in my case, I don’t tend to panic easily. I was able to analyze, and act, appropriately. Because I wasn’t suffering from that startle response.

No big deal.

American 587? Amygdala hijack.

Colgan Air 3407? Amygdala hijack.

AF447? Amygdala hijack.

This flight? Amygdala hijack.

 

[Just a civilian pilot]

When @Astro14 and I stalled the 757-200 multiple times, I was surprised at a couple things.

First, the 757 has very good aileron authority even when stalled. Some small airplanes I've flown, like the Piper Malibu, has almost zero aileron authority when stalled. The Malibu wants to roll over on it's back and it does so with almost no warning. The 757 when stalled will shake the fillings out of your teeth, but it doesn't roll, this is most impressive. @Astro14 will the 757 or 767 spin of you kick the rudder in a stall?

Second, like with the AF 447, we stalled the 757 and held it in a deep stall, then applied full power. The wing makes so much induced drag that even the 757 does not have enough thrust to overcome the drag. If you maintained the stall by holding full back elevator even with full power, you would be in a stall all the way to the ground just like AF 447. It still astonishes me that the two pilots of AF 447 didn't recognize one of the most fundamental aspects of flying any airplane, a stall.

I think they were so confused , and startled, they either didn’t believe what was happening or were overloaded.

I don’t fly with more than one FO in the plane, but if I go wide body with 2 extra pilots on some routes, I won’t leave the cockpit to take a nap unless the weather is o.k.

 

[zuluplus30]

If you are flying in severe ice and tell ATC you need to descend into warmer air to get out of it and they refuse, declare and emergency and descend ( TCAS will provide pilots with traffic separation ).

Reminds me of flights that flew into thunderstorms and for hail damage because ATC would not approve the deviation. Declare and turn.

As a pilot, you are responsible for the safety of the passengers and aircraft.

I just did two weather deviations last month without ATC ( declared an emergency ) clearance because I am not flying into thunderstorms ( non radar oceanic ).

This is pilot error.

People think that pilots can only do what air traffic controllers tell them to do.

That is true of poor pilots. It is not true of good ones.

I said this at the beginning, and it remains true. Staying in icing in an airplane that cannot handle it, is a failure of the crew.

There have been numerous times when air traffic control told pilots they could not do something.

The pilots accepted that, and ended up crashing.

A real pilot would declare the emergency, exercise their full authority, to do what they knew was both safe, and correct, without “permission” from ATC.

Here is an example

https://simple.wikipedia.org/wiki/A...cident in Cove,passengers and 8 crew members.

They accepted holding. They did not make a decision. They did not demand what they needed from ATC.

Agree with everything written here. In the US, this is not normally an issue. Anybody that encounters severe icing immediately goes to the top of my priority list. While we might not "declare" an emergency for them, they get treated as such. I'm moving traffic out of their way as they descend unrestricted. When it comes to TS/WX deviations, while its a bit of give and take as we work people through/around each other, with a bit of pre-planning and advanced coordination, we can generally accommodate anything. In 20 years, I never had a pilot declare an emergency because they didn't get what they needed in regards to avoiding weather.

Unfortunately, foreign ATC tends to be less accommodating.

In the end, the PIC is the final authority regardless of what instructions I give him.

 

[Just a civilian pilot]

In the US, this is not normally an issue. Anybody that encounters severe icing immediately goes to the top of my priority list. While we might not "declare" and emergency for them, they get treated as such. I'm moving traffic out of their way as they descend unrestricted. When it comes to TS/WX deviations, while its a bit of give and take as we work people through/around each other, with a bit of pre-planning and advanced coordination, we can generally accommodate anything. In 20 years, I never had a pilot had to declare an emergency because they didn't get what they needed in regards to avoiding weather.

Unfortunately, foreign ATC tends to be less accommodating.

In the end, the PIC is the final authority regardless of what instructions I give him.

Thanks for the insight and appreciate the help ATC provides for us. I love dealing with U.S controllers.

That said, the only area I have had issues not being allowed to deviate for weather ( aside from oceanic non radar ) is around Nevada because of “ active military airspace”. A few years ago, I heard a SW 737 pilot say he required a deviation within 80 miles but ATC denied it so he declared an emergency and turned anyways. ATC told the pilot to call ATC when he landed and the Captain took over the radio asking why when he gave ATC advance warning , then declared an emergency when refused.

If it happened to me, if I cannot avoid severe weather because of restricted airspace, I would turn around and land where I took off from depending how boxed in I was due to weather and restricted airspace. That would be so rare it’s hardly worth mentioning but made me think about when I heard that flight a few years ago.

Going down to Florida when the weather is severe, ATC is on the ball on puts all pilots on new arrivals coming in ( always make sure you have lots of extra fuel going down to Florida when there are lots of thunderstorms ) to avoid individual flights asking for deviations all the time.

I have only had to declare an emergency 3 times due to ( two lately ) not being authorized to deviate for thunderstorms and both were during non radar NY oceanic.

Weather radar is for weather avoidance, not for penetrating severe solid lines if weather for those who don’t understand weather radar ( not you zuluplus30 ).

Thanks for looking after us , we appreciate it!

 

[Astro14]

Thanks for the insight and appreciate the help ATC provides for us. I love dealing with U.S controllers.

That said, the only area I have had issues not being allowed to deviate for weather ( aside from oceanic non radar ) is around Nevada because of “ active military airspace”. A few years ago, I heard a SW 737 pilot say he required a deviation within 80 miles but ATC denied it so he declared an emergency and turned anyways. ATC told the pilot to call ATC when he landed and the Captain took over the radio asking why when he gave ATC advance warning , then declared an emergency when refused.

This is a case where that Southwest pilot put himself and his passengers at risk. If ATC couldn’t grant deviation around the weather, then maybe it’s time to turn back, hold, or do something else. But wandering into active military airspace, particularly in Nevada, is downright dangerous.

Active military airspace means just that. Fighters, and other tactical aircraft, are maneuvering at high-speed, and under high G.

They may or may not be looking for the airliner that blunders into their war game. They may or may not see it, because they’re busy looking at the airplane at their six. There may be anywhere from one to several dozen airplanes in that airspace. The southwest pilot had no idea how many, or how close, they all were.

The risk of penetrating active military aerospace includes getting shot down, having a mid-air collision, or being too close to ordinance when it’s delivered and explodes.

Also, and I think this really important, when that airliner does blunder into active military airspace, the entire exercise will be called off for safety and every participating airplane will stop their training. Depending on the nature and size of the exercise, you just cost the taxpayers of the US, and perhaps other countries, millions of dollars in wasted sorties. And that pilot may not care, but somebody does.

Now, the military is pretty careful about all that stuff, and I’ve organized several missile shoots.

Those missile shoots took place over the ocean, in W-72 and other airspace, and we made sure that no airliner had blundered off of the prescribed jet airways before we released several missiles at the target.

My point: Declaring an emergency does not change the reality of the situation.

I’ve had this issue arise when debriefing crews after simulator training when they failed to comply with the step down fixes on an ILS in mountainous terrain. In fairness to them, they were pretty task saturated, because I’d already given them an engine failure as a result of a fuel leak or an oil leak. So they had to fly this ILS with an engine out, in addition to the terrain.

I’ve had several captains say “I declared an emergency, so I don’t have to follow that clearance.”

Well, does the terrain know that you’ve declared an emergency? Do the mountains suddenly get lower, or move out of your way, as a result of your emergency declaration?

The exercise of emergency authority can be a double edged sword. You have the authority to do lots of things with your airplane. That’s an important authority.

But just saying “Mayday” does not change the fact that you were flying towards a mountain, or towards active military airspace where you’re subject to increased risk of a mid air collision.