The Transportation Security Administration (TSA) has updated its security protocols for DOT Part 380 public charters, the National Air Transportation Association (NATA) alerted members.

While not detailing the changes—the association noted that they are classified as “sensitive security information”—NATA said it was reviewing the updates to ensure its members clearly understand them. “We encourage FBOs and airports that support or offer public charter services to discuss potential operational adjustments with the public charter operator,” the association said.

The updates have been in the works for some time. In June, the FAA said it was coordinating with the TSA to review security requirements for passenger screening involving public charter flights, as well as other program alterations under the Twelve-Five Standard Security Program. The comment period for those changes was to have ended that month.

Part 380 security has come under scrutiny as certain airlines and pilots’ unions have sought to close operational differences between public charters and Part 121 air carriers. (Public charters often involve Part 135 operators who fly with U.S. DOT Part 380 economic authority). Proponents of such changes have argued unfair economic advantages and cited both security and safety concerns.

As such, the FAA has stated that it is examining changes to the definitions of Part 135 to close some of those gaps, a move it said may push some public charters into the Part 121 scheduled airline realm. In concert, though, the agency also noted its collaboration on the security side for public charters.

Despite this activity, last year a group of lawmakers in the U.S. House of Representatives introduced a bill to close what they called “critical security loopholes,” seeking to require Part 135 operators that fly under DOT Part 380 economic authority with aircraft with nine or more seats to meet the Aircraft Operator Standard Security Program (AOSSP) requirements, which currently apply to scheduled carriers and public charters with a capacity of 61 seats or more. That bill died in the last Congress but highlighted the continuing interest in this area.