The FAA acted “arbitrarily and capriciously” when it reversed longstanding agency practice and precedent by recalibrating its Block Aircraft Registration Request (Barr) program, lawyers for NBAA and AOPA said in their opening legal brief filed yesterday with the U.S. Court of Appeals for the District of Columbia Circuit. The associations argue that the FAA’s revisions to the Barr program are unlawful and should be invalidated. The 13-year-old, congressionally enabled Barr program provides operators of private aircraft the means to opt out of having their aviation movements tracked and available on the Internet in near real-time. Earlier this year, Transportation Secretary Ray LaHood announced plans to severely limit the program only to aircraft owners and operators who can verify a “valid security concern.” The plan to curtail the Barr program, which the DOT claimed was in the interest of “government transparency,” went into effect on August 2. With the filing of the brief by NBAA and AOPA, the FAA now has until September 28 to file a brief of its own in response. The two associations will then have an opportunity to file a final brief on October 12. The court of appeals will hear arguments shortly thereafter.