AIM Text
- When a distress or urgency condition is encountered, the pilot of an aircraft with a coded radar beacon transponder, who desires to alert a ground radar facility, should squawk Mode 3/A, Code 7700/Emergency and Mode C altitude reporting and then immediately establish communications with the ATC facility.
- Radar facilities are equipped so that Code 7700 normally triggers an alarm or special indicator at all control positions. Pilots should understand that they might not be within a radar coverage area. Therefore, they should continue squawking Code 7700 and establish radio communications as soon as possible.
Source: FAA Aeronautical Information Manual · current edition · paragraph 6-2-2.
The short answer
This AIM section is FAA advisory guidance on transponder emergency operation. It tells a pilot in a distress or urgency condition who wants to alert a ground radar facility to squawk Mode 3/A, Code 7700/Emergency with Mode C altitude reporting, then immediately establish communications with ATC. It supports transponder use rules in 14 CFR 91.215.
Research Notes
Common Questions
What code do I squawk to alert ground radar of an emergency?
What does squawking 7700 actually do at ATC?
The AIM explains that radar facilities are equipped so that Code 7700 normally triggers an alarm or special indicator at all control positions, drawing controllers' attention to the emergency.
Will squawking 7700 guarantee ATC sees me?
Not necessarily. The AIM cautions that pilots might not be within a radar coverage area, so they should continue squawking Code 7700 and establish radio communications as soon as possible.