“The Twelve-Five Standard Security Program (TFSSP) outlines requirements for FAA Part 135 certificated carriers offering commercial air transport using aircraft with a maximum certificated takeoff weight between 12,500 pounds (5,670 kg) and 100,309.3 pounds (45,500 kg).” - TSA
On February 22, 2002, the Transportation Security Administration (TSA) published in the Federal Register a Final Rule that required, "certain aircraft operators using aircraft with a maximum certificated takeoff weight of 12,500 pounds or more to carry out security measures." The rule also requires, "certain aircraft operators conduct criminal history records checks (CHRC) on their flight crew members, and restrict access to the flight deck."
TSA defines "Certain aircraft operators" as those conducting operations "in scheduled or charter service, carrying passengers or cargo, or both…" The program that outlines the security measures and requirements for these operators is known as the Twelve-Five Standard Security Program (TFSSP).
NATA Compliance Services (NATACS) can help you comply with the Twelve-Five Program. The following link is a TSA guide on how to complete the fingerprinting process for the CHRC with NATACS.