Why are commercial service airports required to adhere to Part 139, but not general aviation airports? explain iToken=IQoJb3JpZ2luX2VjEAUaCXVzLWVhc3QtMSJGMEQCIEYrcztx8uD0qSuenQ8ymThiWc7wI2%2BHLt%2FJSHA256&X-Amz-Date=20201212T061850Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credent Why is SMS (safety management system) better than […]