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by fredoralive 2178 days ago
What happens if the lockout mechanism breaks and prevents a pilot from selecting gear down when the landing conditions are right?

(I guess they could go for the gravity deployment backup mode, but that would be rather extreme option for a broken solonoid (or so on) on a control lever).

1 comments

Anything can break in a plane which is why you design redundancy into the system. You could provide a manual override switch too.. but at least it would be a conscious act done by the pilot who is aware of the situation.

I can't believe anyone is defending the current UI given we have an obvious example right in front of us of how it can fail.

Actually there is a gear override lever behind the copilot's seat in a hatch in the ground.
I think people are fixating on one problem here as an example of how broken the UI is. What about the problem where a pilot gets great down, does a go around, and forgets to put the gear up? In this case, how could anyone defend not having the plane out the gear up automatically, with warnings?

Just because we have an "obvious example right in front of us" does not mean it is the only failure mode that needs to be considered in the design of the system.

Thank you. There is lots of room for improvement. Why everyone is so intent on defending the status-quo given its obvious deficiencies is mind boggling.
I find your certainty about something you appear to know nothing about mind boggling. Every crash is a deficiency of sorts, so let’s just tell Airbus to build planes that don’t crash! Easy! Let’s just have peace instead of war! Obvious!

It is not sufficient to point out “obvious deficiencies”, one must also point out possible improvements. As other posters (with more patience than I can muster) have pointed out, it is not obvious how to improve this. Putting a lock in place to prevent movement of the lever adds another level of complexity that can itself fail. This is well known and has been extensively studied (a classic paper is No good deed goes unpunished: Case studies of incidents and potential incidents caused by protective systems [0]).

Listen, for example, to this episode of “Undercover Economist” Tim Hartford’s Cautionary Tales [1] (though the example given might itself be problematic [2]).

Airplanes are extraordinarily safe already (look at the amazingly low accident rate, given those fallible, sometimes even negligent and incompetent people that fly them).

Contrary to your facile assertion “There is lots of room for improvement”, there are very few obvious improvements. Change something and you might prevent one accident but enable another one.

As an example: terrorists enter the cockpit. Easy, obvious: lock the door! Ok. Suicidal pilot locks out the other pilot and flies into a mountain. Easy, obvious: unlock the door. GOTO 10. It’s not obvious. These are hard problems that many competent people have thought about in depth. That’s why “everyone” is so “intent on defending the status-quo”.

In other areas, there might be “obvious improvements”, eg regulatory matters, but even there it’s not easy. Aviation is operating within an international framework, there are rules and international treaties and regulatory bodies and stakeholders and so on.

But my main point is that it’s absurd to accuse Airbus of overlooking an obvious improvement without even a cursory understanding of the matter.

[0] https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/prs.68...

[1] https://timharford.com/2019/11/cautionary-tales-ep-3-lala-la...

[2] https://leancrew.com/all-this/2019/11/galileo-and-failure/

> But my main point is that it’s absurd to accuse Airbus of overlooking an obvious improvement without even a cursory understanding of the matter.

Who made such an accusation? The only way you can assume that's my assertion is if you think the UI of an airplane is literally perfect already. If there is room for improvement, which obviously there is, it's not necessarily because anyone was negligent, it's because we're constantly learning and improving.

I find all of your arguments unconvincing and tied to the status quo rather than acknowledging that improvement is possible sometimes even in obvious ways given new information.

Just because there is the potential for poorly thought out improvements, does not mean that every suggested improvement adds a prohibitive level of complexity. You've failed to demonstrate that such a prohibitive level of complexity would be added with my suggested improvement... you've simply asserted it.

On top of everything, you've not provided any credentials showing you know any more about the situation than I do, yet you seem every bit as confident.

> I can't believe anyone is defending the current UI given we have an obvious example right in front of us of how it can fail.

Well, it's also an example of the saying "when you make something foolproof, God invents a better fool". They made enough mistakes here it's clear these pilots were a ticking time bomb; the only way we're fully preventing that issue is to replace pilots entirely with an AI.