AWB 00-16 Issue 1 - Acceptance of Foreign Supplemental Type Certificates (STCs)
Acceptance of Foreign Supplemental Type Certificates (STCs)
AWB 00-16 Issue 1, 17 January 2005
To all owners, operators and maintainers intending to incorporate an STC issued by a foreign country.
CASR 21.114 Foreign STCs states: A certificate (however described) for an aircraft, aircraft engine or propeller that is issued by or for the NAA of a recognised country and is equivalent to a STC that could have been issued by CASA (a foreign STC) is taken to have been issued by CASA for these regulations. CASR 21.114 provides the Australian aviation industry with ready access to certain modifications that have been approved by recognised overseas authorities. This Bulletin clarifies some issues relating to this regulation, to assist the consistent use of foreign STCs.
What foreign Modifications are covered
Foreign Approval Status
The regulation applies to all documents classified as STCs approved by recognised countries and the European Aviation Safety Agency (EASA). It does not cover modifications covered by field approvals, such as the FAA Form 337 or data approved by industry authorised persons in recognised countries or EASA.
Specific cases of modification data, which are not clearly covered by the above, may be referred to CASA for consideration.
The STC must cover the Australian equipment, either by serial number or by other reference, such as all models of a nominated aircraft.
Review of Design Standards for the STC
Aircraft after modification must continue to comply with the certification basis of the aircraft. CASR 21.101, which defines the design standard to be used for an Australian STC is based on similar overseas requirements. Overseas STCs will therefore normally allow the aircraft to continue to satisfy its certification basis. However, a few aircraft have Type Acceptance Certificates (TAC) based on multiple countries, which may have different design standards for the same aircraft. The STC must therefore relate to the design standard issued by the Country against which the TAC was issued.
A modification that changes an Aircraft Flight Manual (AFM) or incorporates a supplement to the AFM is only effective when the STC is approved by the regulatory authority that approved the AFM or other approval methods accepted by CASA.
Responsibilities of persons installing foreign STCs
Approval of Holder of STC
The permission of the holder of the STC is required to install the STC in a specific product, to ensure that continuing airworthiness information is received.
Conflict with other Modifications
The STC is normally approved based on a specific aircraft configuration. As additional modifications are installed, the interface and interaction with those unexpected modifications can be significant. The person installing the modification is required to review the STC and the aircraft being modified and ensure there are no unexpected modifications in the aircraft being modified that will conflict with the STC. The interaction with any such modifications must be evaluated. For complex interactions, specialist technical advice should be sought to ensure there are no adverse consequences. Installation of significant avionic equipment into an aircraft with a FADEC, is one example. Any change to the STC to ensure necessary compatibility must be separately approved.
Advise the Aircraft Register
The CASA aircraft register should be notified when an STC is installed in an aircraft. Notification is mandatory, if:
- the STC changes the aircraft model.
- a new engine or propeller is installed. Unless this occurs, CASA may not be aware of a new type of engine or propeller installed in the Australian fleet, and fail to issue continuing airworthiness information relating to that engine or propeller.
- the aircraft MTOW is changed.
Enquiries with regard to the content of Airworthiness Bulletins should be made via the direct link e-mail address AirworthinessBulletin@casa.gov.au or in writing to: Airworthiness Standards Branch, GPO Box 2005, Canberra, ACT, 2601.