Many obstacles must be overcome before unmanned aircraft systems can be safely integrated into the National Airspace System, the U.S. Government Accountability Office said in a report released last week. Additional work is needed, the report said, to find ways for UAS to sense and avoid other aircraft effectively, to address vulnerabilities in the command and control of UAS operations, and to develop safe and consistent performance standards and regulations. "Concerns about national security, privacy, and the interference in GPS signals have not been resolved and may influence acceptance of routine access for UAS in the national airspace system," the report said.

Legislation passed earlier this year mandated a deadline of 2015 for integrating UAS in the national airspace. The FAA is also facing a deadline of next February to complete a five-year road map for UAS integration, and a final rule governing small UAS is supposed to be completed by August 2014. The report found that although the FAA "has taken steps to meet the requirements set forth in the 2012 Act, it is uncertain when the national airspace system will be prepared to accommodate UAS."