Some reading for Average (and anyone else needing a refresher)
Click on training on the following site
http://www.vbfc.co.nr/
The CASA version
http://www.airservicesaustralia.com/wp-content/uploads/12-039FAC_NCIS-Circuit-training_WEB.pdf
How the virtual USN does it
http://www.users.on.net/~jase_ash/styled-9/styled-11/index.html