Considering that aircraft fly across national boundaries, international practices as mandated by the ICAO, demand that only airworthy aircraft are used in the conduct of commercial flight. Airworthy is a condition where the aircraft is safe for flight.

To protect against wear and deterioration that can lead to catastrophic failures in flight, aircraft are required to be maintained to approved methods and standards.  The maintenance of an aircraft includes preservation, inspections, repairs, overhauls and replacaments of parts.

Licensed Aircraft Engineers (LAEs) are the groups of skilled personnel, who are by law, determine whether an aircraft is safe to be released for flight.  LAEs will certify in writing that the required inspections and maintenance tasks have been carried out properly.

Once the 'Certificate of Release to Service' (CRS) is signed by the LAEs, it becomes a legally binding document and attests to the LAE personal accountability for the aircaft for the technical integrity and safety of the aircraft.