ATC notes: Safety alerts and avoiding action advice


ATC use the terms ‘SAFETY ALERT’, ‘AVOIDING ACTION’ and ‘IMMEDIATE’ either on their own or in conjunction, to notify pilots of information that is of a time-sensitive and safety-critical nature.

It is important that pilots understand the critical nature of these instructions and respond in a timely manner to ensure the safe conduct of flight.

Safety alerts

ATC will issue a safety alert to aircraft, in all classes of airspace, when they become aware that an aircraft is in a situation that is considered to place it in unsafe proximity to:

  • terrain
  • obstruction
  • active restricted or prohibited areas
  • other aircraft.

The safety alert will be prefixed by ‘SAFETY ALERT’ and followed by information or advice on the particular type of threat. This is a trigger for the pilot to commence critical and timely action to ensure safety.

‘SAFETY ALERT’, followed by ‘TRAFFIC’ advice, is high-priority information meant to supplement pilot situational awareness and alert crews to a potential conflict situation.

Avoiding action advice

Avoiding action advice is given in critical situations if ATC become aware that an aircraft is at risk of colliding with another aircraft. Avoiding action advice is only given to aircraft receiving an air traffic surveillance service (this may include the terminal area if the tower has the aircraft identified). Avoiding action advice is prefixed with the term ‘AVOIDING ACTION’ and includes instructions to the pilot for avoiding the other aircraft.

For aircraft outside controlled airspace, but receiving a surveillance service (for example, Flight Following), ATC will prefix advice to turn or change level with ‘SUGGEST’.

Pilot actions and TCAS RA

ATC will not issue safety alert or avoiding action advice when the pilot has already advised action is being taken to resolve the situation or has reported the other aircraft in sight. Importantly, pilots are required to comply with any TCAS RA manoeuvre irrespective of ATC traffic advisories or instructions.

ATC phraseology

The phrases used by ATC when providing safety alerts and avoiding action advice are contained in AIP GEN 3.4.

In high-workload situations these phrases may be abbreviated, however ATC will continue to provide advice conveying the immediacy of the situation and instructions to enable pilots to avoid a collision.

It is important that pilots understand the critical nature of an ATC safety alert or avoiding action advice and react appropriately and in a timely manner.


  • AIP – GEN 3.3–21 Safety Alerts and Avoiding Action
  • AIP – GEN 3.4–25 Phraseologies

Airservices has developed a range of safety educational products to improve the safety and efficiency of aviation operations. These products are available on the Pilot and Airside Safety pages of the Airservices website: