The Federal Aviation Administration has taken steps to protect the air traffic control system from cyber-based threats, but "significant security control weaknesses remain, threatening the agency's ability to ensure the safe and uninterrupted operation," said the report by the Government Accountability Office. There also are inadequate protections to prevent entry into air traffic computer systems from other, less-secure computer systems not directly involved in traffic operations, the report said. Keith Washington, a Department of Transportation acting assistant security, said in a letter to the accountability office that the FAA is aware of the importance of the matter and has achieved several milestones in improving its cybersecurity. Following the report's release, the chairman and senior Democratic member of the Senate Commerce, Science and Transportation sent a letter to FAA Administer Michael Huerta asking for a "full accounting on the status" of the accountability office's recommendations.