An EASA approved STC is applied to aircraft which are nowadays operated in the US under FAA regulations. Does the F&DT still need to be performed? Or could we wait until an actual operator contacts us?
The need to act depends on the date of issuance of the STC approval, see points 26.333 and 26.334. For STCs issued on or after September 1, 2003 the STC holder must perform and submit DTE unless it has already been completed and approved. For STCs issued prior to 1st Sept 2003, the STC holder can wait for an operator request. STC holders do not need to respond to operator requests under this regulation if the operator is not subject to point 26.370(a)(ii), however, the STC holder may be subject to foreign authority requirements as a holder of an STC approved by a non-EU state.