Transportation Secretary Ray LaHood announced Thursday the release of the much-anticipated rule, stating the agency has reached a "major NextGen milestone." FAA Administrator Randy Babbitt, who joined LaHood in the announcement, says the release marks "A step across the threshold. This rule gives the green light for manufacturers to begin building the onboard equipment that will allow our air traffic controllers to know where aircraft are with greater precision and reliability."

As proposed, the rule requires all aircraft that fly in Class A, B and C airspace and above 10,000 feet to be equipped with ADS-B by 2020. FAA expects to have the ground infrastructure in place by 2013. Some industry people and lawmakers pushed for earlier deadlines, but FAA says the 2020 compliance date remains appropriate because airspace users "need to equip. FAA also expects this timeframe will provide sufficient operational experience to make ADS-B the primary source for surveillance."

FAA reauthorization legislation has called for implementation by 2015. But LaHood notes that FAA has been working with Capitol Hill on its plans. As for reauthorization, "what's going to happen is unclear. When the bill is signed, we'll see what it says and we'll follow the law," he says.

The mandate specifically calls for installation of equipment for ADS-B "Out," including either 1090 megahertz extended squitter broadcast link or a Universal Access Transceiver broadcast link. This equipment broadcasts information about an aircraft through an onboard transmitter to a ground receiver. That information then is transmitted continuously to air traffic control. Currently, the refresh rate for air traffic control is 12 seconds, Babbitt notes, adding, "12 seconds is a long time to not see anybody." In addition to continuous transmissions, Babbitt says ADS-B enables controllers to track aircraft in locations where tracking previously wasn't possible, such as the Gulf of Mexico.

FAA considered requiring ADS-B "In" equipment, which would provide more direct benefits ? such as the ability to see surrounding traffic ? but decided against such a mandate. "The agency is mindful, and operators are advised, that ?compliance with this rule alone may not enable operators to take full advantage of certain ADS-B In applications," the agency says. "Operators may voluntarily choose equipment that meets the higher performance standards to enable use of these applications."

Babbitt estimates the cost of the rule (including agency costs) to be between $2.1 billion and $4.1 billion. The actual costs, he adds, will depend on the equipment operators choose. Asked if the Administration has considered providing assistance to offset the costs, LaHood responded that, "We've had several meetings with folks at the White House about this." LaHood acknowledged the costs could be higher for some of the smaller operators, and said, "I think we have the White House's attention on this."

The Aircraft Owners and Pilots Association, however, last week noted that the equipment will cost general aviation aircraft owners thousands but only duplicate what currently exists. "The industry has always maintained that the migration to the new system must be benefits-driven," says Melissa Rudinger, AOPA senior vice president of government affairs. "But the only real beneficiary of this new ADS-B Out mandate is the FAA."

ADS-B Out should be a replacement for transponders, AOPA contends, but FAA is requiring ADS-B Out and transponders. AOPA, however, praised FAA for maintaining a 10-year implementation. "That gives the FAA and industry a decade to work together to find low-cost solutions, such as permitting portable options to display available traffic."

General Aviation Manufacturers Association President and CEO Pete Bunce was pleased with the release of the rule, saying, "The ADS-B program demonstrates successful collaboration between the FAA and industry. This cooperation is essential as we look to deploy other components of the NextGen program." Bunce says the rule puts the standards in place to accelerate modernization, "particularly if we can incentivize operators to expedite the equipage of their aircraft."

Aircraft Electronics Association President Paula Derks says she is "cautiously optimistic that FAA listened to the majority of comments raised by industry." The Air Transport Association, meanwhile, was withholding judgment until it could fully review the rule. "ATA has said repeatedly that any rule requiring this type of equipage and expense must be based on a solid business case," says ATA President and CEO James May.