In the first instance the Operator should establish whether the defective condition is covered by any of the existing approved data, eg. MMEL, CDL etc..
If none of these options are applicable the next step is to contact their Competent Authority to start the process for the issue of a Permit to Fly. At this stage the operator needs to agree with his Competent Authority whether the Flight Conditions are related to safety of the design. If they are not, then the complete process can be dealt with by the CA.
If the CA determines that safety of the design is affected, then the flight Conditions will need to be approved either by EASA, or by a suitably approved DOA. In many cases the TC holder will have privileges to do this, based on previously approved Flight Conditions agreed with EASA.
If the Flight Conditions cannot be approved either by the CA or by a DOA, then an application to EASA using Form 37 will be necessary. EASA will require technical data to support the application which identifies the defective condition (eg pictures of any visible damage), actions taken to minimise the effects (eg statement from the manufacturer supporting the flight), and proposals for the Flight Conditions (using Form 18b) that further mitigate the situation in order that it can be clearly determined that a safe flight can be performed.
Where it is known that Flight Conditions will need to be approved by EASA, application for these could be made in parallel with the application to the CA for a Permit to Fly.