January 1, 2020 not only marked the beginning of a new year, and a new decade, it also marks the first day when ADS-B OUT becomes mandatory in certain U.S. airspace. The graphic above illustrates what the FAA is referring to as ‘rule airspace’ *.
The FAA may grant exemptions to non-complying aircraft on a case-by-case basis via a process called ADAPT, an acronym for ‘ADS-B Deviation Authorization Preflight Tool’. The process involves making application via a dedicated website. The first step is to determine whether an exemption for your aircraft and proposed flight path is available (a transponder equipped with an altitude encoder is a requirement). If there is availability, the applicant is then invited to complete the rest of the questions (mainly personal questions).
Application must be made at least one hour in advance of the planned departure, but no more than 24 hours in advance. Also, it is not a substitute for a flight plan or other ATC requirements; it is in addition to them.
The FAA has provided a five-minute video tutorial that describes the process.
* The rule airspace depicted in the illustration above as Class E from 3,000 to 10,000 feet and located 12 nm out from the coastline is only applicable to the Gulf of Mexico. It is not applicable to other U.S. coastlines.
Image credit: FAA