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Comment by Dalewyn | Hacker News Reader

There is one practical argument that can be made against mechanical switches and buttons, and that is they will eventually fail from long-term use.

I've heard from friends in the aviation industry that pilots take extra care to put as little stress on switches and buttons as possible during normal use to prolong their service live.

The uninitiated might think why bother when a switch or button is dirt cheap, like several cents per unit cheap. And they would be right, the best kind of right. But when a switch/button does inevitably fail and needs to be replaced, the cost can easily come out to at least several hundred bucks between the labor, reinspections, and recertifications among other red tape that help ensure safety.

So if (if!) touchscreen interfaces are more durable and last longer, that is one fair argument in favor of them over mechanical switches and buttons.

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My experience after flying 737, MD80, A320, A330 and A340 is that nobody takes special care with cockpit buttons. They are work tools and treated as such.

The main ones (autopilot and flight controls), rarely fail if at all. The only ones failing from time to time are small switches for radio channel volume or cockpit light adjustments and system buttons at the overhead panel that are easy to replace by maintenance.

Touchscreens are not a good option for main controls due to poor visibility(dirt from fingers and sun reflections), hidden submenus, turbulence making hard to press the correct button…

The A350 and 787 are using trackball controlls for submenus and the onboard computers, not a touchscreen.

I must add that one place where we are using touchscreens is in the fly documentation. Most airlines use somekind of tablet, ipad or surface with apps for performance calculation, navigation charts, pdf manuals, etc… they are working mostly ok now a days and I’dont think you can substitute the touch screen with buttons for that without loosing a lot of functions.

> There is one practical argument that can be made against mechanical switches and buttons, and that is they will eventually fail from long-term use.

Before a touch interface fails from long-term use? I highly doubt it. Plus, a switch is a very easy component to replace. Touch screens can be but aren't always.

I think service life arguments are just poor effort. We well understand the appropriate average service life of a variety of switches. We don't understand the same for touchscreens, especially modern ones, as they haven't been around as long.

> Plus, a switch is a very easy component to replace.

From experience, in aviation nothing is simple or cheap to replace. Cheaper than replacing the entire Garmin unit though, yes.

> From experience, in aviation nothing is simple or cheap to replace.

Of course it is relative but I would still assume a switch in aviation is easier to replace than a touchscreen.

Also the touchscreen is more of a single point of failure. If the touchscreen fails, a whole range of systems and functions are affected. If on the other hand a single switch fails, only one function/system will be affected.

In my twenty years of driving I have had a single manual control fail in a vehicle and it cost less than $50 to get it fixed. I can’t imagine fixing anything on these modern cars being less than several hundred.

Do keep in mind I was talking about replacing failed switches in the context of commercial airliners. As far as ordinary cars are concerned, I agree those would be dirt cheap and easy affairs.

The only people taking special care are the ones that pay for the maintenance.

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