Understanding ADS-B and Emergency Squawks

Modern aviation utilizes a surveillance technology called Automatic Dependent Surveillance-Broadcast (ADS-B). Unlike traditional primary radar, which relies on ground stations to actively detect aircraft, ADS-B allows an aircraft to determine its own position via satellite navigation (GNSS) and periodically broadcast it. This "Dependent" reporting provides Air Traffic Control (ATC) and other aircraft with high-precision data, including identity, position, altitude, and velocity.

The Role of Transponder Codes (Squawks)

Squawk code is a four-digit octal number entered into the aircraft's transponder assigned by ATC. This code correlates the radar return with specific flight data, allowing air traffic controllers to identify and track the aircraft. While most codes are dynamically assigned, specific international codes are reserved to communicate critical onboard situations.

• 7700: General Emergency
  This is the most common emergency code. It signifies that the aircraft is in a state of distress for any reason, such as engine failure, depressurization, or a medical emergency on board. Declaring 7700 alerts all nearby ATC facilities that the flight needs immediate attention and priority.
• 7600: Lost Communications
  This code indicates that the aircraft has lost two-way radio communication with ATC. Pilots will follow standard lost-communication procedures, and ATC will clear the airspace along the aircraft's expected flight path to ensure safety.
• 7500: Hijacking
  This is the code for an unlawful interference, such as a hijacking. The 7500 data shown in this website is intentionally delayed for 2 hours for security purposes.

This website utilizes ADS-B data to track and visualize flights broadcasting these critical status indicators in real-time.