The U.S. Air Force has told bidders for the UH-1N Huey utility helicopter replacement program to include Automatic Dependent Surveillance–Broadcast Out (ADS-B Out) technology in their proposals to enhance safety and navigation efficiency, the service said June 15.

The Air Force said in a statement that it added ADS-B Out to the program’s requirements because the Federal Aviation Administration, as part of its NextGen air traffic modernization effort, requires that aircraft operating in the national airspace have ADS-B Out to help them see other aircraft and hazardous weather and terrain. The new helicopter’s missions will include protecting intercontinental ballistic missile fields in the United States.

The Air Force still plans to issue the program’s final request for proposals in July and award a contract in fiscal year 2018. Potential bidders include a Boeing [BA]-Leonardo team, Lockheed Martin’s [LMT] Sikorsky unit and Bell Helicopter Textron [TXT].