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Comment by post_break | Hacker News Reader

Question, why is 0 a valid entry for autopilot? Would that ever be used?

Typically/historically, autopilot systems have very few checks and controls, mainly because pilots insist that they know better.

Having worked with several autopilots in sims, they are extraordinarily user UNfriendly and unnecessarily complicated.

But, aviation is extremely conservative (and rightly so) and as such, changes and improvements are very small and incremental.

Knowing nothing of aviation myself, I imagine it's the same reason people prefer stick shift over automatic transmission in cars, and command line over GUIs in Unix OSes. It's a matter of favouring superusers/powerusers by leaving them with maximum control of what they want the machine to do. Often times, making a system user-friendly means loss of control and ability to make the machine work its best for you.

There are two situaions in which I love manual drive: long downhill drives (lower gear to use engine for braking) and slippery winter conditions (higher gear to limit engine torque). Automatic gearboxes don't provide enough control to do either of these useful things.

But then, I learned driving with stick, not automatic. I am a representative of your "give me more control" group. Even in other things, I find that there are a lot of automated systems around that do nothing for me because they don't quite behave as I would like and I have not enough control over them to adjust them. The more advanced mu knowledge in a certain area is, the more control I would like to have over related devices.

Do automatics wherever you are have the semi-auto mode where you can select the gear (but no clutch needed)? I find that's definitely sufficient for downhill engine braking. Can't speak to the winter bit though, my car doesn't exactly have a lot of torque to start with... and I generally avoid driving in really slippery conditions anyway.

Automatics with paddle shifters (which I believe first appeared in race cars) are becoming more common (though we may be seeing the end of gasoline-powered cars.) They can be useful on twisting roads, as you can shift down coming into a curve, getting the twin benefits of engine braking into the curve, and a lower gear / higher rpm for accelerating out of it. Traditional automatics would shift up as you slow down for a curve, putting you in the wrong gear on the way out.

Low-power automatics (like the one I rented a couple of weeks ago) can be constantly shifting up and down on long up-grades, unless you lock them in a lower gear.

https://www.theglobeandmail.com/globe-drive/culture/commutin...

There's already a separate interface for that: stick, rudder and throttles.

Altitude is above sea level, and there are airports and areas below sea level. This in and of itself causes all sorts of problems from time to time whenever a programmer forgets this and encodes altitude as an unsigned.

It's really embarrassing to intend to descend to the airport and instead climb to FL4294967295.

I always hate it when I hit the moon on short final...

See my comment above. The pilot didn't actually enter the value 0ft directly, but before take-off, used a mode where the autopilot uses the current altitude as the target altitude. And then got distracted before noticing the problem.

No. But the scale has to start somewhere, and 0 is a convenient number.

Landing?

Different autopilot for that: "autoland". Pretty neat stuff!

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

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