> If they can build a thin metal tube that can safely ascend and descend 30k feet, I'm pretty sure they can build controls that are ergonomic for people outside of a 6" height span. Of all the issues airplane engineers face, I refuse to believe that adjustable controls are the one hill they can't conquer.

How many accidents have there been before we figured out the edge cases with doing this? How many planes _still_ crash due to metal fatigue from pressurization cycles? How many souls are you willing to sacrifice for adjustable controls?

> This is how practically every part of the plane is. There are redundant parts, until maintenance forgets about it.

And just like when maintenance forgets it and there's an incident, it's a big deal. Why accept that risk when there's an easy way to avoid it, especially with potentially hundreds of souls onboard?

> Except here there's a redundancy of a redundancy; the copilot can take over if the other pilot forgot their backup glasses and their contacts broke or whatever.

A copilot is not a redundancy, they're a partial backup. Usually the pilot/copilot split responsibilities. If you push all that onto one person, there are some tasks that they will be less efficient at, if not incapable of performing at all. Yes, most modern airlines can probably be successfully flown by just one pilot, but that pilot is going to have an increased cognitive load to deal with which may reduce their efficiency. In an emergency situation, this can especially be dangerous.

The mantra is "aviate, navigate, communicate" -- when those are split up between two pilots, all three can be accomplished at the same time. When you only have one pilot, something ends up suffering. Hopefully it's just the 'communicate' aspect, but we know in reality it's most often all three that suffer.

Plus the copilot is a human too. Most humans will be a little distracted if the guy they were were working with for the last few hours suddenly died or had a debilitating injury next to them.

> Just put it on the pre-flight checklist. If it's good enough for the mechanical parts, it should be good enough for an already-redundant piece of human equipment.

You'd also need to ensure that the glasses are in good working order, are still the correct prescription..etc. It would not be as simple as 'make sure pilot has extra pair of glasses'.

> If my options are a pilot with glasses or a pilot with high blood pressure, I'm taking the glasses. An effectively blind pilot doesn't cause a distraction, and could be helpful to their copilot (doing radio comms, talking to passengers, maybe watching a gauge or two if they squint). A pilot in cardiac arrest is both incapable of helping and distracting.

Which is incidentally why a lot of pilots are checked for the latter as well. Airlines definitely do require physical checkups for pilots, and that includes cardiovascular health.

> I wouldn't worry that much about a pilot with glasses. The glasses are unlikely to spontaneously break, if they do they should have backups, if they don't have backups then the copilot takes over like anything else that incapacitates a pilot. Hell, if it really came down to the wire, there's probably a decent chance that one of the passengers on the plane has a prescription close enough to make a shoddy landing.

Many, many aviation safety regulations are for edge cases that were written and proved in blood. You do not want your aviation safety regulations to be the equivalent of an italian mechanic going "itsa good!"