I think the best way to describe a safety management system is to say it's a way of forcing operators to develop a system to ensure they are meeting a regulatory requirement.
When I'm talking about this, I often use a very basic example of, perhaps, a taxi company. We might have a regulation that says the brakes on your taxi have to be a minimum of five millimetres thick. In the past we might have been able to ensure that by taking off the tire and looking at the brakes all the time. With a safety management system, what we would do now is to say to the operator that you have to have a system in place to ensure that your brakes never reach below that level of thickness. We would go into his organization and say, "Show us you have the system developed, that you inspect your brakes at a given interval, and that you have it inspected by a person who is duly qualified", and we would check all those records. We might even take off the wheel and look at the brakes while we're there, simply to make sure that everything falls into place. If we see anything that is out of place, that gives us an indication that maybe we have to dig down deeper into the system to see what the problems might be.
The other advantage of a safety management system is that it's incumbent upon the company, if there are deviations in their plans from what they're supposed to be doing, to come up with a plan to improve it and to convince us that the plan they're presenting will truly meet the requirements of the regulations.
I don't know if you want to add anything, Martin.