FAR 21.25(a)(2) states that to be eligible for a restricted category certificate, the helicopter must have been used by the U.S. military. Therefore, any foreign military used surplus helicopter or part is not eligible for FAA certification in a restricted category under FAR 21.25(a)(2). These helicopters were either delivered to foreign military organizations, or were involved in a lend/lease program in a foreign military organization. These helicopters and their components are ineligible for operation in the U.S. because they are known to have been used in foreign military operations.

Foreign Military Helicopter Serial Numbers (PDF)