IFALPA and IFATCA
Background
The growing number of unruly passenger events worldwide poses a significant threat to flight safety and security which requires a coordinated and consistent response to protect crews and passengers alike.
ICAO Doc 8973 (the Security Manual) provides guidance for classifying and managing these incidents, based on a globally recognized framework known as the “4 Levels of Threat”. This framework is designed to ensure a common language for communication and response between flight crews, ANSPS, airlines, and law enforcement agencies such as police and security forces.
However, only a limited number of States have incorporated the “4 Levels of Threat” system into their national security plans. This lack of harmonization can create significant operational challenges, such as misunderstanding between flight crews and ATCOs as to the nature and severity of the unruly passenger event occurring onboard, with the threat being addressed differently depending on the State overflown.
ICAO’s FOUR LEVELS OF THREAT
The ICAO framework classifies unruly passenger behaviour into four levels of increasing severity.
- Level 1 – Disruptive behaviour, including suspicious or verbally threatening behaviour.
- Level 2 – Physically abusive behaviour.
- Level 3 – Life-threatening behaviour.
- Level 4 – Attempted or actual breach of the flight crew compartment.
POSITION
The ICAO classification provides a clear, standardized approach to assess and manage incidents, ensuring that all stakeholders have a shared understanding of the severity and required actions. IFALPA and IFATCA believe that the harmonized implementation of this system in National Security Programs will bring significant benefits, including:
Training consistency: the use of a common system will allow for more consistent training for all the stakeholders implied.
Improved operational safety: assurance that all stakeholders—crew, air traffic control services providers, airlines, and ground responders—are working within a common framework.
Better incident management: standardized threat levels will reduce communications workload and improve coordination, especially in cross-border operations.
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©2026 The International Federation of Air Line Pilots’ Associations, The International Federation of Air Traffic Controllers’ Associations. This publication is provided for information purposes only, in all cases pilots should follow their company’s guidance and procedures. In the interest of flight safety, reproduction of this publication in whole or in part is encouraged. It may not be offered for sale or used commercially. All reprints must credit IFALPA and IFATCA.
