AIM Text
- Pilot.
- Initiates appropriate action if a safety alert is received from ATC.
- Be aware that this service is not always available and that many factors affect the ability of the controller to be aware of a situation in which unsafe proximity to terrain, obstructions, or another aircraft may be developing.
- Controller.
- Issues a safety alert if aware an aircraft under their control is at an altitude which, in the controller's judgment, places the aircraft in unsafe proximity to terrain, obstructions or another aircraft. Types of safety alerts are:
- Terrain or Obstruction Alert.Immediately issued to an aircraft under their control if aware the aircraft is at an altitude believed to place the aircraft in unsafe proximity to terrain or obstructions.
- Aircraft Conflict Alert.Immediately issued to an aircraft under their control if aware of an aircraft not under their control at an altitude believed to place the aircraft in unsafe proximity to each other. With the alert, they offer the pilot an alternative, if feasible.
- Discontinue further alerts if informed by the pilot action is being taken to correct the situation or that the other aircraft is in sight.
- Issues a safety alert if aware an aircraft under their control is at an altitude which, in the controller's judgment, places the aircraft in unsafe proximity to terrain, obstructions or another aircraft. Types of safety alerts are:
Source: FAA Aeronautical Information Manual · current edition · paragraph 5-5-7.
The short answer
This advisory AIM section covers ATC safety alerts. A controller issues a Terrain/Obstruction Alert or Aircraft Conflict Alert when, in the controller's judgment, an aircraft is in unsafe proximity to terrain, obstructions, or other traffic. Pilots initiate appropriate action; the service supports see-and-avoid duties under 14 CFR 91.113.
Research Notes
Common Questions
What are the two types of ATC safety alerts?
The AIM lists a Terrain or Obstruction Alert, issued when an aircraft is at an altitude believed to place it in unsafe proximity to terrain or obstructions, and an Aircraft Conflict Alert, issued for unsafe proximity to another aircraft—with an alternative offered if feasible.
Will I always get a safety alert from ATC?
No. The AIM advises pilots that this service is not always available, and many factors affect the controller's ability to be aware of a developing unsafe-proximity situation. Pilots remain responsible to see and avoid traffic, terrain, or obstacles.
When does a controller stop issuing alerts?
The controller discontinues further alerts once the pilot informs them that action is being taken to correct the situation or that the other aircraft is in sight.