A Certificate of Release to Service (CRS) is a declaration made by appropriately authorised personnel once it has been verified that task being signed for has been properly carried out. Such a declaration is NOT a statement of airworthiness of the aircraft – the obligation for airworthiness sits with the owner/operator.
A CRS must be issued upon the completion of any maintenance carried out on an aircraft and its components once it has been verified that the ordered maintenance has been properly carried out in accordance with appropriate organisational procedures and Part 145 requirements.
It is important to note that a CRS is only related to the scope of work being signed for; it is not a declaration of airworthiness of an aircraft, and does not necessarily constitute authority to fit in relation to components.
In essence, properly performed maintenance restores the aircraft/component to the standards required by the design requirements that themselves have been derived to establish an inherent level of safety and reliability of the aircraft/component.
The CRS statement provides a key input to the ongoing validity of the Aircraft Certificate of Airworthiness [CofA] which is a requirement prior to flight.
. The Certificate should contain as a minimum:
- Basic details of the maintenance that was carried out;
- Date such maintenance was completed;
- Identity of organisation and/or person issuing the release to service
- Limitations to airworthiness or operations, if there are any.
EASA Part M, Subpart H, Certificate of Release to Service — CRS, M.A.801 Aircraft certificate of release to service and EASA Part 145.A.50 Certification of maintenance [EC, 2014]