The FAA’s authority to compel owners of small drones to register them is about to be reinstated, thanks to a provision in the National Defense Authorization Act (NDAA), which passed Congress last week and is awaiting the President’s signature. Specifically, the provision enables the FAA to reinstate the registration requirement for unmanned aircraft weighing less than 55 pounds and more than 0.55 pounds. That requirement was struck down by a federal court of appeals ruling in July.

According to the court, the registration requirement is a violation of the 2012 FAA Modernization and Reform Act, which states the FAA “may not promulgate any rule or regulation regarding a model aircraft.” However, the court ruling left the door open for Congress to change the law.

The Academy of Model Aeronautics (AMA) praised the July court ruling as a reaffirmation of Section 336 of the FARs, which governs the operation of model aircraft. “Federal registration shouldn’t apply at such a low threshold that it includes toys. It also shouldn’t burden those who have operated harmoniously within our communities for decades, and who already comply with AMA’s registration system,” the AMA said in a statement issued at the time.

In December 2015, the FAA instituted mandatory online registration of light drones and a $5 registration fee. More than 500,000 unmanned aircraft were registered during the registry’s first year and the number stood at 770,000 this past March.

Earlier this year, the FAA said that it expected the number of recreational drones in the U.S. to expand from 1.1 million in 2016 to more than 3.5 million in 2021, and the number of commercial drones from 42,000 at year-end 2016 to climb anywhere from 442,000 to 1.6 million by 2021. Manned aviation trade groups praised renewal of the registration requirement as a means of promoting safety and accountability within the National Airspace System.