A modern touch screen is superbly reliable because it has no moving parts, and it can be tested. The (consumer grade) iPad touchscreen is very reliable.
I don't remember any physical light switch that ever switch on or off by itself.
In an aircraft flying through turbulences I'd feel a lot more comfortable knowing that all switches are pyhsical. Try to use your smartphone while jogging...
Yeah they’re both switches, but size is incredibly important, and small mechanical devices are finicky and don’t produce nice clean digital output (that’s a lie that electronic engineers tell software engineers to keep things simple).
So yeah I’m sure you’ve never seen a light switch fail, but I bet you’ve seen a keyboard fail (especially if you’ve spent any time around a recent MacBook).
But I do agree with your point on using a touchscreen in turbulence. A counter point is that there are probably hundreds of controls or settings on a plane that you never touch during turbulence, possibly that you never touch in flight (like telling the flight computer how much cargo you’re carrying). Stuff like that is ideal for a touchscreen.
A cheap phone or tablet hardly represent best of breed for the technology as a whole.
Not if it is in an airplane. Think of all the QC steps required to track the production, storage, shipping, installation, testing, etcetera for the replacement of a single switch. If a switch has failed it needs to be inspected to understand the reason for failure (no switch should fail; tracked to understand if it is a batch failure, plus other steps). I am only making an educated guess here.
> A switch can usually be cleaned easily, to restore its function.
Ummm, you think they put known failed parts back in planes? I think not. They do fix major parts, but the QC for that would be insane. You would make a switch to be hermetic and add anti-tampering - a manufacturer of any safety related device doesn’t want it to be “fixed”. Items are designed to be maintained (with proper schedules), or replaced.
> And proper quality switches can be actuated millions of times before failure.
On average? Or does it have a bathtub curve? Yes, quality switches are insanely reliable, but so are touchscreens.
If you have a variety of 50 switches and knobs, then the reliability is worse than 50x worse, because every item has it’s own reliability curve, and it only takes one failure to muck up your day.
Even less so if it's on the space station. Or on a Mars rover. But we're talking about cars. Something a lot of people like to mend for themselves.
I can say that an intermittent switch failure is hard to diagnose and potentially costly. The dash on a 2007 Ford I got cheaply had an intermittent fault where the whole dash would shutdown, and headlights would go off, while driving. Switching ignition off and on would fix it, so I presumed it just needed a reset. It was actually the barrel switch of the key - intermittent enough to cause a lot of dangerous trouble but hard to diagnose.