What type of communication facility is used at airports with low general aviation traffic?

The correct answer is Aeronautical Advisory Stations, commonly referred to as UNICOM. These stations play a crucial role in managing communications at airports that experience low levels of general aviation traffic. UNICOM frequencies are used for non-control communications, primarily to provide advisory information such as weather conditions, runway status, and other relevant notices to pilots.

At airports with low traffic, the need for an active Air Traffic Control (ATC) presence is reduced, making UNICOM an efficient means of facilitating communications amongst pilots and ground personnel without requiring a full ATC system. Pilots can communicate with each other and receive important operational information through UNICOM, allowing for safe and effective airport operations in such environments.

The other options serve different purposes: ATC is typically established at larger airports with higher traffic volumes to manage aircraft movements directly, while Automated Surface Observing Systems (ASOS) are used for automated weather reporting. The Aeronautical Information Manual (AIM) serves as a reference source for general aviation regulations and information, but does not facilitate real-time communication within an airport environment like UNICOM does.