7500 and 7700: What Do Aircraft Emergency Codes Mean?

An aircraft does not always need a lengthy radio message to alert air traffic controllers to danger. By entering a short code into the cockpit’s transponder, pilots can flag an emergency on controllers’ screens and quickly signal the nature of the problem.

The code 7500 indicates unlawful interference with an aircraft, including a hijacking. It allows the crew to alert controllers to a security threat when speaking openly over the radio may not be possible or safe.

The code 7700 signals a general emergency. It can be used in situations such as a serious technical fault or a medical emergency, but does not identify the precise problem on its own. Controllers need further information from the crew, when available, to understand what assistance is required.

These codes help controllers recognise urgent situations and prioritise their response. They do not replace communication with pilots, but provide an immediate warning that an aircraft may need special handling or assistance.