by Brett_Henderson » Tue Jun 03, 2008 7:49 am
The approach function slaves the auto-pilot to the recieved ILS. It will cause the autopilot to attempt to follow a localizer and glideslope, down to the runway.
However.. if you haven't set the approach up properly, and know how to monitor the approach (as in already know how to fly it manually), it will cause more problems than it solves ..
A back-course function allows for tracking a localizer from the opposite direction.. i.e.. landing on runway 18, using the runway 36 localizer. This usually means no glideslope (else it would be an ILS of it's own, not requiring "reverse" tracking).
These are advanced piloting things.. and trying to understand them, before understanding the basics, will stall your learning... making the whole process longer than needed.