Security

Understanding Aviation Security under ICAO Annex 17

Aviation security in Air Law is governed primarily by ICAO Annex 17 to the Chicago Convention, which sets out Standards and Recommended Practices to protect civil aviation against acts of unlawful interference. Each Contracting State must establish a National Civil Aviation Security Programme (NCASP) and ensure a tailored airport security programme exists for every international airport within its territory. For ATPL students, this forms a core part of aviation regulations and procedures, linking policy at State level to practical, on-the-ground measures that operators, airports, and crews must follow.

Annex 17 defines security measures across the entire passenger and cargo journey, including passenger screening, cabin baggage and checked baggage controls, cargo and other goods security, access control to restricted areas, and elements of airport design that support secure operations. A critical concept is maintaining the integrity of the security perimeter post-screening: if screened passengers come into contact with unscreened persons after the checkpoint, both the passengers and their cabin baggage must be re-screened before boarding. On the customs side, unaccompanied baggage should be cleared using the procedures for accompanied baggage or another simplified customs process distinct from normal cargo handling, preserving both facilitation and security.

States and operators must also manage potentially disruptive passengers, specifically deportees, inadmissible persons (INADs), and persons in lawful custody. Supplementary safeguards can include measures such as boarding before other passengers, appropriate seating, and coordination with escorts, in line with national policy. Where a person is found inadmissible and returned to the operator for removal, the carrier’s obligation to transport that person away from the territory continues until the individual is definitively admitted in another State; the operator is not precluded from recovering transportation costs arising from the inadmissibility, subject to applicable law and carrier conditions of carriage.

In the event of unlawful interference (e.g., hijacking), States must provide assistance, including navigation aids, air traffic services, and permission to land, and take adequate measures to ensure the safety of passengers and crew until the journey can continue. From a flight operations perspective, if a pilot is forced to deviate from the cleared route or level in non-RVSM airspace and cannot communicate with ATS, they should attempt to fly at a level that differs from the standard IFR cruising levels by 1,000 ft above FL290 or 500 ft below FL290. Pilots should employ transponder and communications procedures as feasible and safe, recognizing that actual actions may be constrained by the circumstances. These expectations connect regulatory requirements with practical cockpit decision-making, aircraft systems use (e.g., SSR transponder), and ATS interactions.

What this question bank covers

• State responsibilities: establishment of the NCASP and airport-level security programmes (ICAO Annex 17 compliance).
• Security measures: screening of passengers, cabin and checked baggage, cargo and other goods; access control; airport design features that support security.
• Secure flow management: procedures when screened and unscreened persons mix; re-screening requirements before boarding.
• Handling special categories of passengers: deportees, inadmissible persons, and persons in lawful custody; supplementary safeguards and boarding sequence.
• Carrier obligations for inadmissible persons, including termination of obligation upon admission elsewhere and potential cost recovery.
• Response to unlawful interference: State assistance (ATS, navigation aids, landing permission) and in-flight level selection guidance in non-RVSM when communications are not possible.
• Customs facilitation: treatment of unaccompanied baggage under simplified procedures aligned with accompanied baggage.