# Preventive Security Measures: Screening, Weapon Control, and Rescreening Rules

> Study preventive aviation security measures under Annex 17, including dangerous-object prevention, passenger rescreening, and carriage-of-weapons procedures.

- **Subject:** 010 — Air Law
- **Section:** 010-12 — Security – Safeguarding International Civil Aviation against Acts of Unlawful Interference (ICAO Annex 17)
- **Topic code:** 010-12-04
- **Last reviewed:** 2026-03-27
- **Author:** Pablo Asensio Martínez
- **HTML version:** https://pilotsyllabus.com/en/air-law/security-safeguarding-international-civil-aviation-against-acts-of-unlawful-interference-icao-annex/preventive-security-measures/

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## Prevention of Dangerous Objects
States must prevent the introduction on board of:
1.  Unauthorized weapons.
2.  Explosives.
3.  Other dangerous devices, articles or substances which may be used to commit an act of unlawful interference.

> *Note:* Partially charged batteries or liquids are not intrinsically "prohibited" by Annex 17 as a general category at the same level as weapons and explosives, although they are subject to restrictions (LAGs) at screening points.

## Passengers and Cabin Baggage
*   If there is mixing between screened and unscreened passengers, the passengers concerned and their cabin baggage shall be **rescreened** before boarding.
*   **Special Passengers:** The operator and the pilot-in-command must be **informed** when passengers subject to judicial or administrative proceedings (prisoners, deportees) are being carried. Their "permission" is not required, only notification.

## Carriage of Weapons
*   **Law Enforcement Officers:** Require **special authorization**.
*   Other cases: Weapons must be unloaded and stowed in a place inaccessible to any person during flight time.
*   Pilot-in-command: Shall be notified of the number of armed persons and their location.

## Large Aircraft
For aircraft with a maximum certificated take-off mass of over **45,500 kg** or with a passenger seating capacity greater than 60, the interior design should consider features that make it difficult to conceal weapons/explosives and facilitate searching.

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