Which term describes a situation where an aircraft can no longer receive ATC instructions?

The correct term to describe a situation where an aircraft can no longer receive ATC instructions is "Loss of Communication." This term specifically refers to the scenario where the pilot is unable to maintain radio contact with Air Traffic Control, resulting in an inability to receive vital instructions about navigation, altitude changes, or other operational commands.

In typical aviation operations, maintaining communication with ATC is crucial for ensuring safe and efficient traffic control. A loss of communication can occur due to equipment failure, frequency congestion, or environmental interference, leading pilots to follow predetermined procedures to ensure their safety.

Understanding this concept is important for pilots and air traffic controllers alike, as it forms the basis for emergency procedures and contingency planning during flights. While RADAR failure and other options relate to distinct operational challenges in air traffic control, they do not specifically address the inability to receive ATC instructions.