My book "Angle of Attack" is out!

[seagull]

Mike,

Exactly. I would challenge even most check airman to know all the nuances of all modes of either the Bus or Boeing. The "what's it doing now" joke is a direct consequence of not understanding it, and a clue that you need to learn it more.

On the stall, it turns out the lateral motion is quite a challenge to handle. It goes into direct law and, as you wrote, lateral motion is induced by the aero effects (as Pinker outlined in his paper in the 1963, calling it a "Lanchester" oscillation) and with little damping it is easy to overshoot corrections. This significantly adds to the cognitive workload.

 

[seagull]

First to crash the A320.

First to crash the A330.

First to crash the A340.

First to have major structural damage to the A380.

First to crash Concorde.


.

Accident rates are too low to make that correlation. Like a alleged cancer cluster, this can be chalked up to simply statistical variation.

 

[seagull]

Still, primary instrument training tells you to ignore all body sensations and feelings and look at what the instruments are telling you. Remember, the ONLY thing this crew lost entirely were the airspeed indications. The attitude and heading system was entirely unaffected. At ALL points, the crew had valid pitch/roll information. The altitude and VS indications were momentarily inaccurate, but fairly quickly came back. Regardless, our training tells us to ignore all body sensations and use flight instruments to decipher flight path information.




Ok, so? And they started descending (falling) very quickly and no words were mentioned anymore about still being in a storm. Experience tells a pilot to look at his flight instruments, verify across all 3, decide what looks accurate and then take corrective action.



What part of stall warning am I incorrect? As for not giving the warning credence, the simple answer is because they were clueless, and several times (numerous times) made the comments of "what's happening" "we don't understand, we've lost control" "why isn't it climbing" "but what's happening?" .................... So when you're at the point where no one has ANY idea what really is happening, that would be a good time to heed ANY aural warning coming from the plane. What can you lose? Or at least mention it verbally to the other crew.


It's also Air France. They didn't exactly have a stellar reputation for the 2000 decade (defined from 2000-2009) with 3 major hull loses, 2 entirely fatal.

On the stall warning, the airspeed indication has nothing to do with the stall warning system. However, if you think it does, you are more likely to assume it is a false indication. Have you ever had a stall warning on a transport airplane that was false? I have.

On the rest, true, but you really appear to be discounting the human factors aspects. Humans are not robots that react the same way each time (and a good thing too, as there would be far more accidents if we were!). Sensations, previous experience, training, and confirmation bias all play into it. As we saw recently with Air Canada, once confirmation bias sets in, it is very hard to break out of it. We do not see reality, we see a filtered illusion of it, or at least that is what reaches our brain.

Let me give you an analogy. Let's say you have never driven a car without antilock brakes (very possible today). Of course, you have read that if you are on ice without antilock brakes you need to "pump the brakes" to stop. Now you are on ice and the antilock brakes fail. How do you think this will turn out?

 

[seagull]

Not implying that at all. But those are secondary factors, not primary causal factors. As in, the organizations that produced said pilots, are not the actual physical actions that put a plane into the ground/water. They are the "why" to the primary causal factors that are the "what" and "how" regarding specific actions or inactions that put a plane into the ground, hence why they are secondary/contributing. Just categorizing various factors in their proper spots in order to understand where they relate to the actions ns that occurred. Secondary snd tertiary do not imply "less important" than primary, it only implies where they lie in the factors that answer the what/how/why questions.

If you can attend ISASI, let's talk. I believe that the USAF is now really looking at CAST for investigation, although moving off the intrenched "blame culture " won't be easy.

 

[Nick]

Accident rates are too low to make that correlation. Like a alleged cancer cluster, this can be chalked up to simply statistical variation.

While I get what you are saying and I agree, I thought it would be interesting to the poster I quoted to point out that it appears Air France really has made an unfortunate habit of being the first ones to auger in each type of Airbus.

 

[seagull]

While I get what you are saying and I agree, I thought it would be interesting to the poster I quoted to point out that it appears Air France really has made an unfortunate habit of being the first ones to auger in each type of Airbus.

Are they the largest operator or close to it? Also, the old saying about "A models" might apply as well.

 

[seagull]

I'm going to throw another aspect into the mix. FBW and other highly augmented control systems can introduce inputs that a pilot is totally not aware of. For example, with C* law in cruise flight at altitude, if you just slow down until a descent starts to develop the controls will move to try to maintain 1-g flight even with a neutral stick. That means the elevators are moving up, and it will trim along with it. There is no feedback to the pilot that this is occurring. On a system that is a rate-control, whether that rate is theta-dot or g-dot, it will be acting to provide the _rate_ regardless of what it might take. I could lose half the elevator on my 777 and not get any feedback at all. How does this play into a pilot's mental model for SA?

As an aside (because I keep finding strange changes to what I thought I typed here on my ipad), autocorrect is really annoying at times, but is a good example of automation not always working out the way it is intended!

 

[NovemberEcho]

First to crash the A320.

First to crash the A330.

First to crash the A340.

First to have major structural damage to the A380.

First to crash Concorde.


.

Looks like I won't be flying on an Air France A350 hopefully ever.

 

[Louie1975]

Can the autopilot be used in Alternate Law?

 

[seagull]

Can the autopilot be used in Alternate Law?

No.

 

[PeanuckleCRJ]

Can the autopilot be used in Alternate Law?

On the A320, no.

A330, yes if in ALT 1 and no in ALT 2. There is no annunciation which ALT you're in other than the AP works or it doesn't.

In the 350 and 380, the AP is available in alternate law. If you lose both engines on the 350, the autopilot remains available as well.

Someone mentioned earlier (I think @seagull) that stalling takes you to direct law, which is patently false on all Airbus aircraft. We normally practice stalls in alternate law, and there is even a procedure to put the aircraft into alternate law if low speed protection (alpha prot) kicks in when it should not.

 

[PeanuckleCRJ]

No.

Careful, now... your response varies from completely correct to completely incorrect.

 

[Kingairer]

Is this book 600 pages perhaps?

 

[PeanuckleCRJ]

Are they the largest operator or close to it? Also, the old saying about "A models" might apply as well.

AF was launch customer for the 320 and 340, but not for the 330, nor are they the largest operator (or close to it). NW for a while was the largest 330 operator, and of course they were the ones that had the incidents identical to AF447, but all with successful outcomes.

 

[seagull]

Careful, now... your response varies from completely correct to completely incorrect.

True, I was thinking in response to the AF447 scenario (a bit of confirmation bias or attentional tunneling of my own!), thank you for the quick correction!

 

[seagull]

AF was launch customer for the 320 and 340, but not for the 330, nor are they the largest operator (or close to it). NW for a while was the largest 330 operator, and of course they were the ones that had the incidents identical to AF447, but all with successful outcomes.

Thanks, I really had no idea, so was just asking the question. As to the NW events, as I recall in each of those cases you had at least one person up front that had experience flying jets prior to RVSM rules, etc., am I correct?

 

[seagull]

On the A320, no.

A330, yes if in ALT 1 and no in ALT 2. There is no annunciation which ALT you're in other than the AP works or it doesn't.

In the 350 and 380, the AP is available in alternate law. If you lose both engines on the 350, the autopilot remains available as well.

Someone mentioned earlier (I think @seagull) that stalling takes you to direct law, which is patently false on all Airbus aircraft. We normally practice stalls in alternate law, and there is even a procedure to put the aircraft into alternate law if low speed protection (alpha prot) kicks in when it should not.

I don't think I ever said that stalls take you into direct law, as that would definitely not be true. I have discussed the roll mode in ALT 2 being direct law, is that what you're referring to?

 

[seagull]

AF was launch customer for the 320 and 340, but not for the 330, nor are they the largest operator (or close to it). NW for a while was the largest 330 operator, and of course they were the ones that had the incidents identical to AF447, but all with successful outcomes.

On the topic, I think the alpha-floor is one of the more brilliant ideas that Airbus came up with.

 

[PeanuckleCRJ]

Thanks, I really had no idea, so was just asking the question. As to the NW events, as I recall in each of those cases you had at least one person up front that had experience flying jets prior to RVSM rules, etc., am I correct?

Given that even I have been flying jets since before RVSM, yes, they all had said experience with certainty, and years of it.

I don't think I ever said that stalls take you into direct law, as that would definitely not be true. I have discussed the roll mode in ALT 2 being direct law, is that what you're referring to?

Be careful on your wording, as it is extremely important... ALT 2 is a flavor of "alternate law," which is the overall FBW regime that you're in. Direct law is another overall FBW regime with protections all gone.

Aileron control in ALT 2 is directly controlled by stick input, but it is not in "direct law." The difference, while subtle, is critical. She is twitchier in the roll, but it isn't awful... the 330 is very very stable with the phase length of control input to response almost twice as long as the 320. The 320 series has a much higher roll rate and is downright touchy in the roll in alternate and direct law (I've had the real thing in both laws in flight). One characteristic to note about the 330 in the roll is its behavior in heavy turbulence- it tends to wobble around up to about 7-10 degrees of bank.

 

[PeanuckleCRJ]

On the topic, I think the alpha-floor is one of the more brilliant ideas that Airbus came up with.

Truthiness! Very telling that Boeing put a virtually identical function on the 777 and beyond with identical inhibit windows, but just different enough to where they tout it as their own.