Airworthiness is a term used to describe whether an aircraft has been certified as suitable for safe flight. Certification is initially conferred by a Certificate of Airworthiness (CofA) from a National Airworthiness Authority, and is maintained by performing required maintenance actions by a licensed Aircraft Maintenance Engineer. Required scheduled maintenance actions are detailed in the Aircraft's System of Maintenance. Minor inspections are typically every 100 flight hours, with more intensive maintenance inspections at longer intervals.