Years as since humans have flown planes stable enough not to need constant attention. On a calm day you don't need autopilot, just set your trims correctly and some airplanes will hold course well enough for a short nap - though of course this is more likely to result in a crash (which likely has happened, though it is hard to guess why a plane crashed beyond pilot error)

▲

stavros 3 days ago | parent [-]

Yeah, but a 1% angle over a long period of time intersects with the ground, and I wouldn't want to trust your alarm clock with 200 lives.

	▲	schoen 3 days ago \| parent \| next [-]
		The pilots would get an extra "Woop! Woop! Terrain! Terrain! Pull up! Pull up!" redundant alarm clock, although it's terrifying to rely on it.
	▲	bluGill 3 days ago \| parent \| prev [-]
		I wouldn't want to either, and even the pilots who have done it claim accident. It has worked out for a lot.