There are currently 553 airports in the U.S. that hold Part 139 certificates. These certificate holders serve scheduled and unscheduled air carrier aircraft with more than 30 seats. These certificate holders also may serve scheduled air carrier operations with air carrier aircraft with more than nine but less than 31 seats.

SMS is a formal approach to managing an organization's safety through four key components — safety policy, safety risk management, safety assurance, and safety promotion.

According to the Federal Aviation Administration, this proposal will help airports enhance safety by developing an organization-wide safety policy; implementing methods to mitigate airport hazards; and analyzing and mitigating risks before they change airport procedures or infrastructure. The proposed rule requires that SMS be used for airport movement and non-movement areas which includes runways, taxiways, ramps, aircraft parking aprons, and fuel farms. The FAA believes that SMS will provide an additional layer of safety at airports and help reduce airport incidents and accidents. Airports will have the flexibility to implement a SMS plan that considers their unique operating environment.

While the proposed SMS requirement will not take the place of regular FAA Part 139 inspections, this proactive emphasis on hazard identification and mitigation will provide airports with robust tools to improve safety.

Airports are identified by four classes, depending on the type of air carrier service at the airport. The proposal states that Class I airports would be required to develop a SMS implementation plan within six months and implement within 18 months after the final rule is published. The remaining Class II, III, and IV airports would be required to develop a SMS implementation plan within nine months and implement within 24 months after the final rule is published. The FAA will review and approve the SMS implementation plans.