FAQ n.22061

What is the classification criteria for Basic STCs?


The classification criteria for Basic STCs are stipulated in the current TIP for Airworthiness and Environmental certification between the FAA and EASA at paragraph and are here listed for your convenience.

Major design changes to a TC, including STCs, are eligible for a basic classification if not impacting any of the following items:

  1. Any item in the VA Safety Emphasis Item (SEI) list as defined in paragraph;

    Please consult the EASA lists of SEI for General Aviation and Rotorcraft published at this link.

  2. The CA or VA certification basis includes or is anticipated to include a new or amended:
    (i) FAA exemption or EASA deviation;
    (ii) Special condition; or
    (iii) Equivalent level of Safety (ELOS/ESF);

    Please note that this information is typically quoted in the FAA STC.

  3. A classification of “significant” has been made by the CA in accordance with FAA 14 CFR section 21.101(b) or EASA 21A101(b);
  4. An AD is affected that was issued unilaterally by the VA; or an AD is affected that was issued by the VA, and where the VA is the Authority for the State of Design for the TC; 
  5. Changes involving the use of a new or different applicable method of compliance from that previously agreed by the CA and the VA;

    Note: A method of compliance (MOC) would not be considered “new” or “different” if it had been applied previously in a similar context by both the CA and the VA.

  6. New technology exists;

    Note: New technology is technology that is new to the VA as a whole, not just new to the VA team members. For example, if technology used by the applicant were new to the VA team but not the VA itself, it would not be considered new. It is the VA management’s responsibility to make sure the VA team members are properly informed of the earlier use of the technology, VA standards and MOC.

  7. Novel applications of existing technology exist;

    Note: Novel application of technology is where a particular technology is being used in a manner that causes the precepts of the technology to be questioned. However, it does not mean that existing technology being applied for the first time to a particular product line is automatically novel. Additionally, novel applies to the VA as a whole, not just to a project being assessed by the specific VA team members.

  8. The applicant has proposed to the CA non-simple substantiations of acoustic or emissions changes, whereas a simple substantiation is when the compliance demonstration with the CA has involved standard means of compliance and procedures which were already regularly agreed by the VA and CA in previous projects of the same applicant (using the same test organization).
  9. Changes that have an appreciable effect on any one of the Operational Suitability Data (OSD) constituents (refer to EASA Guidance Material GM 21.A.91 to determine an appreciable effect); and
  10. Any other design change designated as Non-Basic by the CA.

CA stands for Certificating Authority, i.e. the FAA in this case

VA stands for Validating Authority, i.e. EASA in this case

Please note that applicants may not have all the elements and information required for a correct classification. Therefore, the classification proposed by the applicant may be questioned by EASA and eventually not accepted.

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