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Comment by Ntrails | Hacker News Reader

It makes me really sad that young children will never get the experience I had when flying, of going into the cockpit during a flight and looking at all the buttons and talking to the pilot. :(

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A child in the cockpit once accidentally disengaged some controls which eventually resulted in a crash that killed all 75 people on board.

https://en.wikipedia.org/wiki/Aeroflot_Flight_593

> One of the children had unknowingly disengaged the A310 autopilot's control over the aircraft's ailerons while seated at the controls. [...] With the autopilot active, Kudrinsky, against regulations, let the children sit at the controls

I remember visiting the cockpit pre-9/11 and it did not include being invited to sit at the controls. Or, in other words, children visiting the cockpit was probably more the proximate cause than the root cause.

There is a difference between letting a child in the cockpit and having him sit in the pilot seat, as it was the case in the Aeroflot Flight 593 crash.

The child sitting at the controls was the pilots child, that's the reason for the increased (but certainly unacceptable) access.

This is actually an odd case, as it was mainly the result of improper training and different configurations between two planes. In a Boeing plane, autopilot will never disengage without specifically being disengaged. In an Airbus plane, giving a 'harsh' enough input will disengage the autopilot. The pilot here mainly had experience on Boeing, so was not aware of this minor but very important difference.

The Air France flight that crashed into the Ocean by Brazil was also partly the fault of different designs by the two major aircraft manufacturers. In Boeing planes, the input is synced between the pilot and copilot (if one pulls up, the other physically moves as well). In Airbus planes however, the input is merged together instead. If one pilot pulls up, and one is pushing down, nothing really happens.

This ended up partly leading to the crash, as one pilot heard the stall warning and pulled up (causing more speed loss), while the other pilot correctly pushed down. If the inputs were synced, the other pilot likely would have noticed his copilot was making the wrong input.

> In Airbus planes however, the input is merged together instead. If one pilot pulls up, and one is pushing down, nothing really happens.

Which is just crazy! I wonder who the product manager who thought "what should happen if one pilot is pushing on the stick and the other is pulling? I know, just average them and fly straight" was. There are various things you can do in that situation that would kind of make sense (the Boeing design being the best), and that is not one of them.

They might have thought "there is no sensible answer in that case, so just have the behavior be the natural operation of the existing systems as designed" which turned out to be adding the inputs.

Except that there is a sensible answer: you physically force the two controls to synchronize.

Once you settle on a design where the two controls move independently of each other, then yes, there's no sensible answer. But, don't do that.

Even then, anything else would make more sense, for example "the left stick always has priority and the right stick flashes a red 'disabled' light", or anything else.

Agreed. No solution will be good, but there are definitely less-awful ways than averaging the inputs.

I suppose what the Parent was getting at, is that it doesn't make any sense to have two sets of completely disconnected flight controls in the cockpit. That's a lot like having two different mice plugged into your computer at once...

I can't think of a situation that would warrant one flight control being pushed and the other pulled...

Most aircraft have both sets of flight controls physically connected (either via direct links, or actuators driven by flight computers). So if one pilot pulls back, the other set of controls comes back as if it's being pulled on. One of the advantages of this design is both the pilot and copilot can be aware of what the control input is at any given moment.

> The Air France flight

More information for those interested. It's a long read.

Or, you know, the captain could have told the co-pilot "I have control" as they are typically trained to do in handling emergency situations!

> This is actually an odd case, as it was mainly the result of improper training and different configurations between two planes.

That might be the case, but I would rather not be on a plane where children are allowed inside the cockpit. Parents can visit an aviation museum if they want to.

That transcript is harrowing.

Seems kind of similar to the plot of the Grisham novel Airframe.

s/Grisham/Crichton

Well, not just as a kid for me. One pilot showed me just how much work the autopilot did by turning it off and turning our glassy-smooth commuter jet ride into a bumpy and alarming one. I hope the other 150 people in the cabin didn't get as worried as I did!

One of my fondest childhood memories was nearly crashing a three story ferry into the side of a canal after the captain let us hold the wheel. He very quickly took over and I doubt we were ever in danger, but I can definitely understand a reluctance to let kids even stand close to the cockpit controls. It's all wholesome until an engine shuts down!

It's nowhere near the same, but I remember being a little kid back in '96 (maybe '97, I'd have to call up my mom and ask) and getting to ride up front with the monorail pilot at Disney World.

Anyhow, kids aren't the only danger in the cockpit. Around the same time, I rode in a Bell helicopter with family members during a local festival. An older cousin in his 60s at the time sat up front with the pilot. Trying to "get comfortable," he'd slammed his foot against one of the pedals and managed to bump the cyclic in his surprise. Needless to say, the pilot wasn't very happy once we landed.

Shouldn't the pilot have instructed him to keep his feet off the pedals before takeoff? Seriously, a minute going over safety procedures with a neophyte and nothing would have happened.

I'd assume he did, because it's kind of an obvious thing in hindsight. But I was pretty young at the time, so I don't really have a clue beyond what stuck in my memories.

A couple of times in the 1990s I 'drove' a steam locomotive [1], with coaches, on the tourist railway not too far from where we lived.

I was about 9 or 10, and was only just strong enough to push or pull the regulator (controls how much steam is allowed into the piston). The driver explained the important gauges, like the boiler water level and pressure, and showed the tiny view ahead which he had to use to look at signals. And the shelf above the firebox, which could be used to keep tea warm.

[1] One of these: https://en.wikipedia.org/wiki/SR_V_Schools_class

For some children, a brief moment in the airplane, locomotive, boat, whatever, cockpit can be enough to inspire dreams and future aspirations.

It needs to be done safely of course, but as a child, seeing into the airplane cockpit was my favorite part of the trip. All the buttons and switches, and the uniforms the pilots wore... it all dazzled me as a young child. To this day, I still desire to fly an airplane...

I completely agree and I'm grateful I had so many similar opportunities. As a child I had been in airline cockpits and at the controls of a few boats (my father worked in marine operations) and I can definitely associate those experiences to my love for systems and technology. Especially systems with switches!

Unfortunately the systems I work with only have switches written in code. Perhaps I should rig the deploy process up to a sturdy industrial switch panel for fun.

Eh, it's not that bad, just do it before or after the flight.

Source: Did it as a child twice

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