The FAA released a policy memo on March 2 that updates guidance on installation of ADS-B out systems, essentially allowing avionics shops to install ADS-B equipment on aircraft not covered by a supplemental type certificate (STC) without having to obtain a new STC. This new policy, said Bill Stone, Garmin senior business development manager, “significantly reduces cost, downtime and uncertainty about how long the aircraft is going to be down.” The installer does have to obtain permission from the original STC holder.
Earlier in the ADS-B upgrade process, the FAA was requiring that each aircraft model have its own STC. “The agency was pretty concerned as new equipment hit the market to ensure that it worked correctly,” Stone explained. “The original policy was that it could be installed only via STC. That would maintain a high level of involvement and ensure that aircraft entering airspace [where ADS-B is required] are operating as intended and not bringing the system to its knees.”
The FAA eased the requirements somewhat a few years ago, allowing approved ADS-B transmitter and GPS position source pairings–once STC’d–to be field approved in other aircraft models. “This is less of a cost and time burden than an STC,” he said, “but it does require FAA involvement, and that could inject FAA time and uncertainty and additional cost.”
Now the FAA has issued the new policy, and basically if the installation is a major alteration, it will still need field approval. This may be the case where a new antenna needs to be installed on a pressurized airplane, for example. A simple ADS-B out installation in a non-pressurized airplane will be a minor alteration, and it can be signed off by an A&P mechanic holding an Inspection Authorization or a Part 145 repair station. “It doesn’t call for FAA involvement at all,” Stone said. “Basically we’re talking a radio installation; it’s not major surgery.”
Stone sees this new policy as offering major benefits to helicopter operators. “There are so many makes and models, it’s not financially viable to try to STC every one.” In a recent situation, a Texas sheriff department operating MD500s and Sikorsky 300Cs already equipped with Garmin GNS 430Ws (which provide the required position source) and GTX 330ES transponders (which meet the ADS-B out requirement) couldn’t get approval to use the installed equipment for ADS-B out. There were no STCs available and little incentive for an avionics shop to go through the expense of engineering and seeking approval for an STC. The new policy allows this operator to modify the installed equipment as a minor alteration to achieve ADS-B capability, thanks to Garmin’s existing approved model list STC for ADS-B out using the same equipment.
There should be many more similar cases, affecting a variety of aircraft from helicopters to even some business jets. Stone did warn that there is a caveat: for aircraft that exported out of the U.S. at some point, the new regulatory authority might require a specific STC. “You’re better off going with an STC for turboprops and jets that are not destined to remain domestic,” he said.
“It’s nice to make a little progress,” Stone concluded. “We’re all after the same thing; we’ve got a big fleet to upgrade [by Jan. 1, 2020]. Lifting the system out of one airplane and putting it into another is low risk.”
