Comment by willidiots | Hacker News Reader

Comment by willidiots | Hacker News Reader

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Entirely speculating, but it sounds like the fundamental problem is that they had a confused Captain and First Officer who both thought they were the Pilot Flying. Human factors / psychology issue. Sure, on a Boeing you'll feel the other pilot's input, but if you're tired enough, or panicking because the plane's not doing what you expected, you might not get the hint.

Task saturation - followed by loss of situational awareness - is a very real problem in today's airliners, particularly during takeoff and approach/landing. You're trying to do a ton of things in a small amount of time, while dealing with a dynamic situation outside, and in this case after a long, tiring flight over the Atlantic.

There are a great series of (dated but still good) videos from American Airlines about automation dependency, human factors and the simple but very real problems that develop as a result - often leading to panic and disaster when things go wrong. Search YT for "children of the magenta".

In the AF447 case, the lack of feedback/linkage of the Pilot Flying / Nonflying sidesticks was a big contributing factor. It is true that the Pitot tubes froze up. But the Pilot was roused from his sleep, entered the cockpit, and correctly pointed out that the plane was actually in a dive. It's just that the guys flying were making opposite inputs over an extended period, and it was too late to recover, which doomed AF447. Overall, Airbus and its delinked sidesticks was a factor in the accident.

I thought Boeing did not have sidesticks, and the yokes/control columns are linked to give actual feedback (to emulate most airplanes, which do this with mechanical controls). Is that not the case?

That does seem to be what was happening here, as both pilots thought the plane was fighting their inputs, but in reality they were fighting each other.

There were lots of things that went wrong with AF 447 but the side sticks were a minor detail. If anything the stall warning going on and off was a much bigger factor because the one pilot kept pulling back on the stick which is the exact opposite of what he should've done. Had the pilot flying simply flown pitch and power they would've been fine and had plenty of time to calmly troubleshoot the situation.

> I thought Boeing did not have sidesticks, and the

> yokes/control columns are linked to give actual feedback

> (to emulate most airplanes, which do this with mechanical

> controls). Is that not the case?

Boeing's philosophy seems to be to provide physical feedback for most or all of the controls. So, yeah, the control columns are linked (even on fly-by-wire planes like the 777 and 787). But that's not very useful once you're dealing with startled and/or panicked pilots. Take a look at the Atlas Air or Sriwijaya Air crashes.

The problem with Air France has nothing to do with Boeing or Airbus and everything to do with pilot standards and training. At this point Air France is lucky. Look at the Air France incident in 2020 (A318). Or their incident in Bogota in 2017 (A340). Or the 2011, 2012 x2, and 2013 incidents where the Airbus (A320/321) alpha floor protection prevented an Air France crew from crashing on approach to Marseille x2, Hamburg, and Tel Aviv. At some point Air France's luck will run out.

> If anything the stall warning going on and off was a much bigger factor because the one pilot kept pulling back on the stick which is the exact opposite of what he should've done.

Private pilot here.

This is so hard. It’s not an excuse, especially for professional pilots.

But I can share from experience how much your “animal brain” fights you in this situation. Pulling back leverages lift in most normal flight, until you go too slow (stall), and then you suddenly very much need to do the opposite. But the normal behavior becomes second nature, like walking.

My examiner in 2020 said the biggest thing the FAA was stressing about was a serious uptick in incidents with slow flight (and stall) handling during takeoff/landings.

A year ago, we had an experienced local private pilot wreck his plane (lucky no major injuries) succumbing to exactly this. Took off, lift conditions a little worse than normal, started to leave ground effect, felt the plane stall, pulled back, started losing altitude, panicked and pulled back harder, tailed down and fell side wards. Plane totaled. He recounted to me after how he knew what to do. He’s trained multiple times. Done lots of stall recovery. Has done many many short field takeoffs (which is similar, pop the plane off the ground and then stay low to build speed). But was still chagrined at how panick/situation management got the better of him that time.

Being master of your animal brain in all situations is hard. And you never know, because you can never test all situations.

Sure. There are some things in aviation that are counterintuitive: recovering from a stall is one of those. That's why commercial aviation in the United States places such a strong emphasis on regular training (and why commercial aviation in the US is as safe as it is). Unfortunately stall physics are something that flight simulators don't tend to do so well at.

Another counterintuitive thing is that tactile feedback isn't necessarily helpful. There's a lot of whinging about how Airbus doesn't provide any feedback in the sidestick when both pilots are doing conflicting things, same with the thrust levers (or whatever they're called in Airbus land). Pilots have crashed Boeing airliners that give you this "important" feedback.

Anyways, my point was that stall recovery is something that's usually drilled into pilots. Unfortunately for the AF 447 crew, nobody told them that the stall warning would turn off when they flew so far outside the envelope that they were in "undefined behavior" territory. And that led to at least one of the pilots not recognizing that they'd stalled in the first place. But like any crash there are many contributing factors, and if any one of those had been different the plane wouldn't have crashed.

If it were just one or two examples of poor airmanship at Air France then sure, it'd be easy to chalk it up to "flying is hard". And yeah, the pandemic has robbed a lot of pilots of their necessary practice. But the four or five cases I cited where Airbus' "alpha floor protection" saved Air France flights were all pre-pandemic. At some point you've gotta look at what those incidents and accidents have in common (hint: it's not the airplane and not the crew). And that's why my main concern is with Air France's lack of safety culture and by extension their pilot training.

> commercial aviation in the United States places such a strong emphasis on regular training

This in a nutshell is why I never completed my Private Pilot training. As I got close to taking my checkride I began to think about finances going forward. And I realized that I probably couldn't afford to fly often enough to keep my skills sharp and a dull pilot is a dangerous pilot.

25 years later I'm still alive so I think I made the right decision :-)

The transcripts of AF447 include the pilot telling the right seater to stop. More than once. But he keeps doing inputs.

Airbus 320 pilot told me there is a light that comes on when inputs dont match.

Now reread the transcripts with the assumption that the right seater might not have the best intentions.

What do you mean by best intentions? There are more efficient ways to crash a plane.

But also isn't the right seater the first officier, surely he should obey a repeated direct order from the captain.

The captain was asleep. Maybe there were no clear consensus on chain of command in the cockpit.

By convention the left seater is the captain. In the case of AF447, the captain was asleep, and the FO and a relief pilot were flying the plane.

> Overall, Airbus and its delinked sidesticks was a factor in the accident.

Confused, Bonin exclaimed, "[Expletive] I don't have control of the airplane any more now", and two seconds later, "I don't have control of the airplane at all!"[29]

Robert responded to this by saying, "controls to the left", and took over control of the aircraft.[73][32]

He pushed his side-stick forward to lower the nose and recover from the stall; however, Bonin was still pulling his side-stick back.

The inputs cancelled each other out and triggered an audible "dual input" warning.

--

So in an Airbus this situation is unambiguous - the plane tells you plain and simple: Both pilots are trying to fly at the same time. With a mechanically linked set of controls, you don't necessarily know whether you're fighting the other pilot or the plane.

> my airplane

> your airplane [lets go controls]

Those are the words to be exchanged to avoid confusion.

Yeah, simple enough. Also simple enough to go-around when you're obviously slow and going to be short of the runway, but look at Asiana 214.

I do wonder if there's some training deficiency or cultural issue that leads to this scenario in Air France flights.

This makes me think of Loic Suberville's videos on language...

Sure, just make sure that happens exactly that way 1,000,000 times without any failures…

And that’s the root of many issues in aviation. It works 99.99% of the time is not always good enough.

I wonder if this was part of some rare coincidence where their inputs were perfectly synchronized but out of phase in such a way that it made it difficult to consider the obvious. If you pull back but feel the plane and/or stick move laterally, and especially across multiple inputs without a clear pattern, it might more easily occur to you to think the person sitting next to you is also providing inputs. Whereas if you're synchronized across many inputs, that's just something that doesn't typically happen in nature, which tends to always have some stochastic quality; instinctively it's something you might assume would only involve a machine.

> my airplane

> your airplane

> my airplane

"I have the airplane" or "my airplane" is an established practice, but over and above that, the stick/yoke/rudder pedals all actually give you feedback when the other guy is also handling them. That feedback gives the fliers another level of protection.

Agreed, but also given they initially thought the aircraft itself was deviating from a stable approach (or at least the ATC transcription appears to suggest that?), perhaps the pilots may have thought the feedback was due to autopilot and not the person sitting next to them.

Well this is terrifying. Their only job is to pay attention and communicate clearly…especially during takeoff and landings

Most people are not good at their jobs...

Most people don't get to fly airplanes.

As pointed out by a sibling comment, cockpit resource management training solves this very simply by verbally declaring who should have control.

As usual, Star Trek was out in front with CRM on how to verbally switch commands:

1. I'm losing command

2. I've got command

https://www.youtube.com/watch?v=RAvRBDQqSmY

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