Adlerdriver

Hardly the same thing. One, I seriously doubt the captain pitched the aircraft in the attempt to control his erroneous airspeed using full aft stick and held it. Two, since both crew members were able to see his yoke, they were fully aware of what he was doing with it (regardless of whether they agreed with the inputs or felt like they could say anything). Three, I wasn't suggesting that a pitot-static malfunction has never lead to an aircraft loss.

My point was simply that the other crew members on AF447 had no idea that Bonin was holding full aft stick. That would not be possible or at least extremely unlikely on another aircraft type.

ShyGuy

Perhaps

As for a pitot-static accident, there was a Northwest Orient 727 out of New York that was empty except the crew and the pitots were blocked (due to ice IIRC) and all 3 airspeeds acted as altimeters and read high values. The crew commented this must be because they were so light. They continued pulling back, stalled, they were above 10k feet but couldn't recover and ended up crashing.

You are correct that the Airbus design did help to mask what Bonin was doing. I'm just not convinced the outcome would be different for *sure* , given Boeing crews that have crashed due to either 1 or all 3 pitots blocked (BirgenAir and Northwest Orient crews, respectively).

Adlerdriver

Shy,
It really doesn't seem like we're on the same page. I understand that there have been pitot-static failures resulting in hull losses. Yes, Boeing crews can (and have) put their aircraft out of control (why not thrown in Aeroperu 603 for good measure). However, I think the rather benign flight path and nature of the flight control inputs required to lose control of the AF447 aircraft from cruise altitude are considerably different from any of the accidents you mentioned.

I have to strongly disagree with your opinion that this specific accident could have happened in a non-Airbus aircraft. Let's just say Boeing for the sake of the discussion, especially since I've only flown Boeing and Airbus. The main thing I think you're not considering is the nature of the stall warning system on a Boeing.

The AF447 crew exceed the flight envelope in less than one minute from the initial auto-pilot disconnect. This was achieved via persistent full aft stick input by the PF in spite of multiple audible voice stall warnings. These stall warnings eventually stopped due to system logic. Consider the ease as which an Airbus pilot can bring the pitch control input to full aft. A simply tilt of the wrist aft with a relatively short travel to the aft stop, barely perceptible to his crew member in the darkened cockpit.

In order for a Boeing pilot to do the same thing, the PF would have to apply considerable back pressure, bringing the yoke in close proximity to his abdomen as well as the PNF's for more than a minute. Impossible to ignore, IMO. Additionally, once the stall warning activated, the presence of the stick-shaker would be continuous. Also practically impossible to ignore, unlike a voice warning that can be tuned out as events increase the saturation level of the crew.

In my opinion, it took some extreme and persistent misapplication of the flight controls to place that A330 outside it's flight envelope in a deep stall. I just don't see that being possible in most aircraft equipped with a conventional flight control configuration and stall warning system.

ptarmigan

The aircraft stalled prior to full aft stick. You are also ignoring the flight control logic which would apply full aft elevator regardless of stick position once it starts to lose altitude (absent pushing forward which would require knowing you were stalled). Depending on the failure mode (look up integrated modular avionics) you could get the same in the Boeing, and in both cases it can result in full nose up trim for the horizontal stabilizer with no pilot input.

METO Guido

Problem is, airplanes just don't understand Just Culture. Pitch angles above 15 degrees can't be sustained at FL350.

ptarmigan

"In social psychology, the fundamental attribution error (FAE), also known as the correspondence bias or attribution effect, is the claim that in contrast to interpretations of their own behavior, people place undue emphasis on internal characteristics of the agent (character or intention), rather than external factors, in explaining other people's behavior. The effect has been described as "the tendency to believe that what people do reflects who they are".[1] "

Adlerdriver

Would it have stayed stalled if he let go? From what I read, the deep stall developed as a direct result of his post-stall continuous aft stick input (commanding the elevator to trim full nose up). Correct?

Must be some strange Euro-logic. Without a target altitude to maintain and the auto-pilot off, why would flight control logic command full aft elevator in response to altitude loss? If a crew clicked off the A/P at cruise and began to descend, is that going to trigger full aft elevator?

METO Guido

I'm a golfer, believe me, I know. Had my head up the caboose once or twice in the airplane too. Okay, maybe more than twice. Which is why we rely on the other guys/gals to set us straight. Sometimes..pitch, bank, yaw and power; that's all you get.

ptarmigan

It is a function of C* law. Both Airbus and Boeing it is g-dot command at higher speeds/altitudes, vs theta-dot (pitch rate) when slower/lower. Hence neutral stick is attempting to hold 1-g flight.

One of my concerns is that we don’t teach this stuff so pilots really do not have an understanding to the point they can anticipate what the automated systems will do.

ptarmigan

Prior to stall entry the correct answer would be “it depends”. Early on, probably not, as it got closer, likely yes.

On the second question, on a constant rate descent you’re at 1-g so that is fine, it is responding to the change, g-dot, not steady state case.