"I do think autopilot technology has helped reduce the number of plane crashes."
Ryan - What I find very disturbing over many years of experience and observation, is the number of accidents that have been instigated or facilitated by the inappropriate use of autopilot functionality. For example, aircraft that plunged to the ground needlessly in Indiana and Buffalo thanks to pilots remaining on autopilot in icing conditions and chatting away as the airframe got loaded up to the point where the AP disengaged and handed the clueless pilots an un-flyable machine. Even if a pilot is unaware of icing he will soon become aware that something is wrong if hand flying because he will detect and/or note the changes in trim or need for additional power, etc. Flight 401 went down in the Everglades because the entire cockpit crew was obsessed with a gear indicator light and nobody was in charge of flying the plane, so nobody noticed when a bump on the yoke by the captain disengaged the AP and they gradually flew down into the swamp.
I could go on and on with endless examples and, just like the single vs twin debate, somebody could cite the accidents that never happened due to the extra engine or give anecdotal stories about the pilot who but for the autopilot would have crashed after falling asleep, however thanks to being on autopilot when the engine started sputtering it woke him up and he was able to skillfully and expertly perform a dead-stick, off-airport landing. Wow! What a pilot!
I have my own rule for autopilot use, and that is to disengage and fly manually whenever more than one flight path parameter needs to be changed. For example, a change in heading during cruise... no problem. Change in heading and altitude and/or airspeed? I'm doing that myself because, frankly, I can do it better or sequence things optimally in a way that is far more difficult to do by telling the autopilot what to do, waiting to see what it does and then providing any required feedback. I also find that when I am "flying" the plane I am more engaged with the world outside the cockpit and have better overall situational awareness... I feel like I am part of the machine and it actually reduces my workload because in a high-load environment like flying into New York in IMC I find the flying part of the job (including the scan) is like riding a bike. It's hard to explain, but for me it's just easier to be firing on all cylinders than to be figuring out which ones I might not need at the moment.