Security, Facilitation and Accident/Incident Investigation
This domain separates three different regimes: security (Annex 17), facilitation (Annex 9) and investigation (Annex 13).
Security
Annex 17 and, in Europe, Regulation 300/2008 require national security programmes, airport and operator security programmes, screening of passengers, cabin and hold baggage, cargo and mail (with known consignor arrangements), protection of the security restricted area, and control of access to the critical parts of that area. The cockpit door remains locked and access is controlled. Acts of unlawful interference trigger the operator's contingency procedures and the SSR 7500 code.
Facilitation
Annex 9 covers the formalities that ease movement: immigration, customs, health, and the documents required from passengers and crew. It is about smooth clearance, not security screening.
Investigation
Annex 13 defines an accident and requires the State of Occurrence to institute the investigation, not the State of Registry or Operator. States of Registry, Operator, Design and Manufacture are entitled to appoint accredited representatives; the sole objective is prevention, not apportioning blame. The report contains findings, causes and safety recommendations, issued to the authorities that can act on them.
In Europe, Reg. 996/2010 governs investigation and Reg. 376/2014 governs occurrence reporting with a "just culture" framework.
Worked example
An aircraft registered in State B, operated by State C's airline, crashes in State A. State A investigates. States B and C, and the States of design and manufacture, may each appoint an accredited representative and advisers.
Traps that cost marks
Naming the State of Registry as the investigator; treating an Annex 13 report as evidence of legal liability; confusing Annex 9 facilitation with Annex 17 screening; forgetting that occurrence reporting has its own timelines and safety-data protections.