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Comment by lisper | Hacker News Reader

Private pilot here. This story buries the lede. There were tail strikes, which can be serious, but usually aren't, and in this case weren't. But the reason there were tail strikes is because software told the pilots to take off with throttle settings that were too low, and that could very easily have ended catastrophically. If takeoff power settings are too low and the pilots don't notice in time, you can end up in an unrecoverable state where the aircraft cannot take off but there is not enough runway left to abort. The passengers and crew on these flights got very, very lucky that it was "just" a tail strike.

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>> The data “confirms that the airplane was safely airborne with runway remaining and at an altitude by the end of the runway that was well within regulatory safety margins,” said the union’s Alaska unit chair, Will McQuillen, in a statement.

Sure, but you're missing the point. This particular bug produced an erroneous output that resulted in a tail strike. A different bug, with all the other circumstances unchanged, could have produced an erroneous output that resulted in a catastrophe. One should not shrug this off as "oh, it was just a tail strike, therefore it was no big deal." It was very nearly a very big deal.

If the data was too far off it is likely the pilots would have noticed it. This was a situation where it was off, but still "sane," so went unnoticed.

The airline completely grounded their entire fleet while they investigated this issue, so I don't really understand why you're trying to act like nobody took this seriously. The article makes it quite clear this was handled as a serious problem and steps taken.

The Alaska Airlines' pilots union is both qualified to have an opinion AND looking out primarily for their members (i.e., pilots), and they had this to say:

> The data “confirms that the airplane was safely airborne with runway remaining and at an altitude by the end of the runway that was well within regulatory safety margins,” said the union’s Alaska unit chair, Will McQuillen, in a statement.

If the union was unhappy with the remediation steps taken, they'd say so. That is quite literally their primary function.

> This was a situation where it was off, but still "sane,"

No. The margin for error in jets is very small. Jets are much less forgiving than Cessna 172s. The difference between a tail strike and a failed takeoff is very small, easily under the threshold of human perception until it's too late. Also, the whole point of using this software in the first place is so that every takeoff is done right on the hairy edge of minimal performance. It is a catastrophe waiting to happen. This was a wakeup call.

> If the union was unhappy with the remediation steps taken, they'd say so.

It is quite possible that no one in the union appreciates the broader implications. Pilots are generally not software engineers.

So your point is that professional airline pilots, their union, or an airline are less qualified to understand the safety implications of this incident than a PPL because that PPL is also a software engineer? Are you familiar with the Dunning–Kruger effect[0] and how it may be playing a role in your perspective of this incident?

[0] https://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect

> because that PPL is also a software engineer?

Not just for that reason. I'm also not bound by the political constraints that union leaders are. They have to pick their battles. I'm free to say whatever I want about this with little risk to my career.

But yes, I think I understand software -- and particularly software risks -- better than most pilots, and I think I understand flying better than most software engineers, so I think that makes my opinion better informed than most. (It is nonetheless just an opinion.)

> Are you familiar with the Dunning–Kruger effect

Yes. Are you familiar with the ad hominem fallacy?

https://en.wikipedia.org/wiki/Ad_hominem

> Are you familiar with the ad hominem fallacy?

It doesn't apply. When an argument is backed by someone's qualifications (in this case PPL and software developer), discussing the merit of those qualifications for the discussion domain is absolutely relevant. Your first reply to this thread started off with:

> Private pilot here.

And now that I'm calling into question how relevant that is, or more to the point if you're in a position to know better than the pilot union/airline/etc, it is suddenly Ad hominem.

Cannot have it both ways, either your qualifications make your opinion more relevant or they don't. But pick a lane.

The implication with calling it Ad hominem though is that your qualifications aren't relevant, which I happen to agree with, and actually that was my point.

You don't seem to understand that Dunning-Kreuger effect. Let me quote from the article that you cited:

"The Dunning–Kruger effect is a cognitive bias whereby people with low ability, expertise, or experience regarding a certain type of task or area of knowledge tend to overestimate their ability or knowledge."

In other words, by invoking D-K, you have implicitly said that you think I am a person "with low ability, knowledge, or expertise" regarding the matter at hand. But I am a licensed private pilot with 30 years of flying experience, and a software engineer with a Ph.D. and over 40 years of professional experience, including over 15 years working at NASA and at an aerospace startup I co-founded. Those are all just facts. In the face of those facts, an implicit and unsupported assessment that I am a person of "low ability, expertise, or experience" is an ad hominem, essentially saying, "Yeah, you have all these credentials, but you still might be an idiot." Well, yeah, I might be. There are lot of idiot pilots out there, and there are a lot of idiot software engineers out there, and I may well be a member of both groups. One of the big problems with idiocy is that it does not yield readily to introspection. (And you might want to mull that over a few times before you respond.)

As long as I'm pointing out your logical fallacies, here's another one:

> your point is that professional airline pilots, their union, or an airline are less qualified to understand the safety implications of this incident

No, that is not my point, which makes this a straw-man [1]. The fact that neither the union nor the airline have publicly expressed the same concern that I have in no way implies a lack of expertise on their part. There are many other possibilities, one of which is that they agree with me, but they are savvy enough to realize that there is nothing to be gained by saying so publicly.

[1] https://en.wikipedia.org/wiki/Straw_man

> But I am a licensed private pilot with 30 years of flying experience

So you have the lowest pilot qualification who can even solo, and no jet qualifications at all. But you know better than the pilots union at a commercial airline, who are run by commercial airline pilots? Or the FAA who haven't stepped in after TWO reportable events? So, yes, absolutely Dunning–Kruger applies here, and the fact you don't seem to see that is a problem.

Heck, you think "I am a software developer" means anything in this context is also a mystery to me.

> In the face of those facts, an implicit and unsupported assessment that I am a person of "low ability, expertise, or experience"

You are though. You only have PPL, and seemingly don't even know what it is that you lack in terms of expertise. The fact you think you know better than people who are demonstratively more qualified to have an opinion is problematic, it is textbook Dunning–Kruger.

If you knew more you'd be embarrassed but what you're saying here.

> The fact that neither the union nor the airline have publicly expressed the same concern that I have in no way implies a lack of expertise on their part.

They did express that concern, it is in the article. They even shut down the airline for a period because they were so concern at not insignificant cost to them.

Is it too late to point out that understanding of the Dunning-Kruger effect is subject to a pop-psych Dunning-Kruger effect?

Nope. :-)

> you have the lowest pilot qualification who can even solo

First, that's not true. Student pilots can fly solo, and there is also a sport pilot rating with is in some sense "lower" than a PPL. So the PPL is actually right in the middle of the primary rating hierarchy.

But more importantly, your characterization of a PPL as the "lowest pilot qualification" implies a pretty profound misunderstanding of how pilot ratings work and in particular how they relate to operational knowledge. It is possible to fly a jet with a PPL, and it is possible to get an ATP without ever flying anything beyond a Piper Arrow. There are also all kinds of orthogonal ratings like an instrument rating, seaplane rating, multi-engine rating, and instructor rating. And absolutely none of those things have anything to do with flying jets. For that you have "type ratings" [1], which are more or less orthogonal to all of the others.

> You only have PPL

That is also not true. I have additional ratings beyond the PPL, I just haven't mentioned them because they are not relevant. What is relevant is that I actually fly airplanes, and so in general I probably understand the process of flying an airplane better than someone who does not fly airplanes, and I have actually written and deployed software in mission-critical situations, and so in general I probably understand mission-critical software and its attendant risks better than someone who has not.

> They even shut down the airline for a period

No, "they" did not shut down the airline. A single individual, Bret Payton, shut it down.

> If you knew more you'd be embarrassed but what you're saying here.

Could be. But at least I know the difference between "but" and "about".

[1] https://en.wikipedia.org/wiki/Type_rating

When you claim he is affected by dunning kreuger you are by definition attacking the person instead of the argument. Hence "ad hominem"

Then when stating the authority of pilots and their unions you are not attacking the argument with a counter argument. Instead you claim you are right because of the authoroty of the union. Hence argument from authority.

Fallacious arguments. Clearly.

Ad hominem, argument from authority.

I agree with almost all that you said, but I seem to remember that Air Florida flight 90 crashed killing almost everyone aboard because the throttle settings were too low and no one figured it out until they were airborne and out of ground effect.

They had too much thrust, not too little.

Nope.

Yep. When you add thrust in an airliner, the nose pitches up, aggressively. Too little thrust and the nose would not make it off the runway.

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