The reporting of acts of unlawful interference with civil aviation provides ICAO with data that is critical to evaluating and analysing security incidents and trends. Contracting States are obliged by legal instruments and Annex 17 to the Chicago Convention to report to ICAO as soon as possible after an incident has been resolved. In accordance with Annex 17, each Contracting State must provide pertinent information on every incident of unlawful or attempted seizure of aircraft or aviation facilities. Through analysis of such occurrences, experts are able to develop effective measures that form the keystone of an aviation security programme.
 
To facilitate this process, a reporting form is provided in the Security Manual for Safeguarding Civil Aviation Against Acts of Unlawful Interference (Doc 8973 – Restricted). The Official Report on Act of Unlawful Interference, is available as Appendix 10 of Volume V of the manual, Crisis Management and Response to Acts of Unlawful Interference, and requires information on any action taken to remedy identified weaknesses in order to prevent recurrence.