Most airports voluntarily implementing SMS are taking around 5 years to gather data for trending. A typical implementation is around 3 years. If you check out the rule (see link below), the FAA is offering different timelines based on the size of the airport so not all will have as much time. I’ve been working with airports since 2008 including a number of FAA pilot studies and we have seen a wide array of benefits including better collaboration with airlines and air traffic by formally assessing safety hazards related to airside construction. Airports in Canada and Europe have been operating an SMS for more than 10 years and have found positive results. Hopefully for most airports this won’t be a paper exercise and they will benefit from the system safety approach. https://www.faa.gov/airports/airport_safety/safety_management_systems/external/part_139_SMS_subpartE_draft