What does "squawk" refer to in aviation?

In aviation, "squawk" refers to the command given to a pilot to set a specific transponder code that will identify their aircraft to air traffic control (ATC). When a pilot is instructed to "squawk" a certain code, it means they should input that numerical code into their aircraft's transponder, which broadcasts that code along with the aircraft's altitude. This allows ATC to track the aircraft on radar and provides important information about its location and flight status.

This terminology is crucial for maintaining situational awareness and ensuring safe navigation in controlled airspace. By designating a unique transponder code, ATC can easily differentiate between multiple aircraft, enhancing communication and safety in busy air traffic situations. The functionality of the transponder and the use of specific codes are fundamental components of the air traffic management system.

The other options do not accurately capture the meaning of "squawk." Navigation techniques and emergency procedures do not involve the transponder's code-setting function, and while pilots may communicate via signals, that is a different aspect of aviation communication not specifically linked to the term "squawk."