[timthorn]

Landing is typically done on autopilot these days; it is done manually to maintain a pilot's rating or for exceptional reasons.

[notahacker]

Actually, the exact opposite is true - pilots must use autopilot on a certain number of occasions to retain their certification to use it on low visibility approaches, but otherwise generally do so only when visibility is severely restricted.

[yardie]

...and under fair weather conditions. Under more adverse conditions will be done manually.

It's fairly easy to tell a computer, "See that line (runway slope), follow it".

[willyt]

I think the autopilot follows a ILS beacon in. Isn't that why less flights are diverted in poor weather now? http://en.m.wikipedia.org/wiki/Instrument_landing_system http://en.m.wikipedia.org/wiki?search=Autopilot

[borism]

Landing is almost never done by autopilot. Approach is. When the runway is in sight Pilot Flying has to take over from the autopilot, and gently put the wheels on the ground. Computers are still not very good at it, especially not when there is slightest deviation from the norm (i.e. crosswind).

Autoland is very rare and is either used in ideal conditions or in terrible conditions (but then both aircraft and airport AND flight crew have to be rated to Cat IIIc standard - extremely rare occurrence).