Some questions in reference to certifying ADS-B Out in an aircraft via field approval seem to arise every now and then. While most equipment OEMs attempt to obtain Approved Model Lists (AML) for their STCs, some aircraft operators and maintenance providers may attempt to seek ADS-B approval by installing GPS receivers with transponders that have not been previously approved by the FAA.
While this sort of alternate ADS-B approval method may be possible, it certainly would not be the ideal method. That is, the FAA is very clear in that for an ADS-B Out installation to be approved the pairing of the GPS and transponder must be “previously-approved” under type certificate (TC) or supplemental type certificate (STC). Click Here to reference subject matter “Installation Approval for ADS-B Out Systems” on FAA Memo dated Oct 10, 2012 . Despite this certification and approval detail, all GPS and transponder manufacturers are still not completely on the same page in relation to one OEMs equipment playing properly with another OEMs equipment. Some improvements in relation to OEM compatibility continue to be made as the deadline approaches, however it is still not a 100% known whether all GPS and transponder OEMs will work together in relation to ADS-B Out interfaces.
In addition, most GPS manufacturers frequently make software changes in their units which might affect the ADS-B functionality to the transponder. As of the date of this article, OEMs are not obligated to share proprietary information that would enable or otherwise affect the ADS-B Out interface between varieties of equipment. For reference, click Here for a document that provides a list of “FAA-Approved” ADS-B Out Avionics as of April 3, 2014. While this list will obviously continue to be updated and expanded, it is important to reference since it lists what transponders have been approved to be used with “approved position source(s)”.
As indicated above, the FAA will not approve any ADS-B Out field approval if the transponder and associated position source are not on this list. Likewise, installers and integrators should be cautious when attempting to interface GPS and transponders that are from separate manufacturers unless both manufacturers have approved the interface. Southeast Aerospace will continue to provide the most up-to-date, realistic information regarding the ADS-B Out mandate and how it affects all parts of the aviation industry. Please be on the look out for future SEA white papers, commentaries, and other reference material as the 2020 mandate approaches.