Installing the skyBeacon on an aircraft not listed on the AML is approved by the FAA.  A field approval is not required.  Under the FAA Memo titled “Installation Approval for ADS-B OUT Systems,” the FAA explains that after an STC is achieved for ADS-B OUT equipment, additional installations can be accomplished on aircraft not listed under the AML STC by an A&P with Inspection Authorization (IA) so long as the installation does not require airframe modification.