An aircraft’s basic configuration has a type certificate (TC). All retrofit equipment installed must be approved with a Supplemental Type Certificate (STC). An STC means that the certifying civil aviation authority has approved both the system and its installation from an airworthiness viewpoint.
Within the EU STCs are mainly issued by EASA. An STC issued by FAA (Federal Aviation Authority in the USA) is in reality the same as global certification. CTT and Lufthansa Technik have a co-operation agreement regarding certification.
This agreement means that Lufthansa Technik acts as CTT:s formal design organization and maintains STCs for CTT products. Lufthansa Technik has an excellent reputation for certification, and affords the possibility of maintaining STCs from both EASA and FAA.