An incident is any occurrence, other than an accident, associated with aircraft operation that affects or could affect safety, per ICAO Annex 13 definitions used globally in regulation and investigation practice. A serious incident is an incident with a high probability of an accident and is subject to investigation standards similar to accidents under Annex 13 Chapter 5 criteria and guidance. Annex 13 distinguishes accidents by fatal/serious injury, substantial aircraft damage, or missing aircraft status, setting the legal boundary between incident and accident frameworks
Accident vs incident
An accident requires fatal or serious injury, substantial structural damage affecting performance, or an aircraft being missing or inaccessible, as codified in Annex 13 and widely referenced by operational safety resources. An incident is any other safety-affecting occurrence linked to operations that does not meet the accident thresholds, forming the broader category for hazard capture and learning. Both accidents and serious incidents are investigated with the sole objective of prevention, not apportioning blame or liability, under Annex 13 principles.
Global investigation rule
Annex 13 requires States to investigate accidents occurring in their territory and to investigate serious incidents, with notification, preliminary reports within 30 days, and final reports as soon as possible or within 12 months when feasible. The Annex defines State roles, participation rights, and report structures to standardize cross-border aviation safety investigations and data sharing. ICAO clarifies that investigations aim to improve safety frameworks via findings and safety recommendations rather than establishing fault allocation in civil or criminal contexts.
U.S. reporting rules
49 CFR Part 830 mandates immediate notification to NTSB for accidents and specified serious incidents, with a 10-day written report for accidents and incident reports upon request, establishing clear timelines and triggers. Immediate notification incidents include flight control malfunctions, in-flight fire, midair collision, uncontained turbine failure, serious avionics failures, and significant runway events, among others, per §830.5. The NTSB provides a formal portal and instructions reiterating the immediate notification duty for accidents and certain incidents for all operators.
EU reporting rules
Regulation (EU) No 376/2014 requires both mandatory and voluntary occurrence reporting, with organizations and listed professionals submitting within 72 hours of awareness, standardizing timelines across Member States. The Regulation embeds just culture protections, mandatory data fields, taxonomy via ECCAIRS, and centralized exchange to the European Central Repository within 30 days for harmonization and analysis. EASA’s Easy Access Rules consolidate obligations and confidentiality safeguards to encourage high-quality safety reporting across the system.
Who is responsible
Pilots are responsible for compliance with operational procedures and timely occurrence reporting under national frameworks, and can be mandatory reporters in the EU lists when acting as PIC. Operators must ensure training, maintenance, compliance monitoring, and organization-level reporting systems that meet mandatory 72-hour timelines and quality requirements, including risk classification. Air traffic services personnel are mandatory reporters in the EU and provide data essential to Annex 13 investigations and occurrence analysis pipelines.
Legal consequences
Civil liability can arise from negligence proven against operators or individuals when incidents reveal deviations from required procedures or failure to report, independent of Annex 13’s non-blame investigation objective. Regulatory penalties can be imposed for non-compliance with notification, reporting, and safety management duties under national rules (e.g., NTSB Part 830 timelines) and EU occurrence reporting obligations. Criminal exposure is reserved for gross negligence or willful misconduct in some jurisdictions, but Annex 13 processes remain safety-focused and distinct from judicial proceedings.
Preventive controls
Implement systematic occurrence reporting aligned to Annex 13 and, where applicable, 49 CFR Part 830 or EU 376/2014, meeting immediate notification and 72-hour submission standards with complete mandatory fields. Maintain just culture policies and confidentiality processes to ensure reporting volume and quality, leveraging ECCAIRS taxonomy and quality checks required by EU rules. Integrate investigation lessons and safety recommendations from State reports into training, SOPs, and audits to reduce recurrence and demonstrate proactive compliance.
U.S. quick checklist
- Notify NTSB immediately for accidents and listed incidents under §830.5 triggers to preserve compliance and investigation integrity.
- File the 10-day accident report; submit incident reports when requested; preserve wreckage, records, and data per Part 830 Subparts C and D.
- Use NTSB reporting resources and maintain internal logs to evidence timelines and completeness in the event of oversight review.
EU quick checklist
- Implement mandatory and voluntary reporting systems with 72-hour submission, risk classification, and required fields per Annex I of 376/2014.
- Ensure designated reporters across roles (PIC, maintenance, ATC, ground handling) and data exchange to the European Central Repository within 30 days.
- Apply just culture protections and quality assurance processes to reduce underreporting and improve data consistency across organizational databases.