What are Cirium's sources for aircraft accidents and what is the coverage?

We have a range of sources for our accident data:

• All media and social media channels.
• Google news alerts.
• Discussions with insurance industry participants including loss adjustors which can highlight claims previously unreported.
• The expert insight of the Fleets data team who are constantly monitoring the global fleet - they sometimes discover accident damage repaired aircraft in storage where an accident was previously unreported.
• Official (country-level) accident investigation web sites.

Accident coverage by class:-

• Western-built jet airliners and regional jets – complete since entry into service.
• Eastern-built jet airliners – complete since entry into service.
• Western-built turboprop airliners and commuters – complete since entry into service.
• Eastern- built turboprop airliners and commuters – complete since entry into service.
• Business jets – complete since entry into service
• Twin-engine business turboprops – complete since 1990
• Single-engine business/utility turboprops (excludes agricultural aircraft) - complete since 1990
• Western-built turbine helicopters (excluding Soloy Bell 47s etc) – complete since 1990 plus many earlier accidents
• Eastern-built turbine helicopters – complete since 1990. Some earlier accidents
• Western-built piston helicopters (production types excluding Bell 47, Brantly, Hiller UH-12) – complete since 1990. Some earlier accidents.
• Other Western-built piston helicopters i.e. Bell 47 and UH-12 – new accidents being added as they happen.
• Eastern-built piston helicopters – being researched.
• Newer twin-engine piston general aviation aircraft – being researched back to 2000.
• Piston ‘utility’ types e.g. DHC-2 Beaver, BN-2 etc – new accidents being added as they happen.
• Certain single-engine piston general aviation aircraft – new accidents being added as they happen.
• Older twin-engine piston general aviation aircraft – new accidents being added as they happen. 
• Older single-engine piston general aviation aircraft of more than about five seats - new accidents now being added as they happen.
• ‘Pure’ military aircraft types – we use best endeavours to add new accidents as they happen.