I don't think autopilot landings are legal, even if they are possible. Autopilot is mainly to keep the plane flying straight and level, as far as I've ever heard.
I don't have a legitimate source, this is just something I read. Some planes, thought not all, are able to land themselves in the event of an emergency.
Jeanette Isabelle
All autopilot systems in commercial airplanes are certified for specific types of operations. All of these require the crew to actively monitor the operation of the autopilot. Certification for coupled approaches (auto landing) requires extensive proofs that the system is fault tolerant and capable of landing safely under a wide range of landing conditions. This is the most demanding certification for an autopilot system and all of the currently certified autopilots are designed to disconnect when faults are detected and return control to the crew (along with aural and visual announcements of the fault).
There are no civil autoflight systems that are designed or certified to safely land the airplane in the event of an emergency. Having said that, I'll note that if the pilots were incapacitated the autoflight systems may make it possible for a less trained individual to safely land the airplane. This is not part of the design or certification criteria for the system and goes along the lines of some chance is better than no chance at all.
To the best of my knowledge military systems have similar or even more restrictive limitations.
Most people would be surprised at how little the crew may be doing in a commercial jet - after rotation (takeoff) the various systems are theoretically capable of performing the rest of the flight, including the landing and approach with minimal pilot intervention.
This is my work field (avionics systems engineer) and I have a pretty extensive background on both general avionics and flight control systems for both large military jets and commercial jetliners. In general, the autoflight systems of smaller airplanes are less capable due to the costs of developing and maintaining the systems to the safety levels required. The benefits (in $) just don't justify the costs for smaller planes.
- Eric