Approach hold:  The autopilot will try to intercept the gildeslope and automaticly do the descent for you. Althogh you still need to control speed and flap settings etc. There are many topics concernign his matter, I warmly recommend you to search the forum for more info  

Back course: The correct term for this is Localizer Back course approach, since you make use of the localizer to track the centerline of the runway. It works in the similar way as would a normal LOC approach. As you know the localizer is a radio signal transmitted from an antenna situated at the end of the runway you're appoaching. But the localizer does not only transmit a front course signal, but also a back course signal. But here's the catch: your Course Deviation Indicator  will work in the reverse way. You must fly "away" from the needle in order to fly toward the centerlline. This is VERY tricky since it against your natural instincts. Normally you'd roll right when the CDI deviates to the right, but on a back course you'd roll LEFT. However it's very neat when you get the hang of it. Very useful on airports only equipped with only 1 localizer antenna per runway.


I made a picture to illustrate the concept.

P.S. When should I use the LVL button?

Most modern autopilots default to the level mode, when the autopilot master is engaged. When heading or NAV is selected, this will turn off the LVL mode. Some basic autopilots ONLY have a LVL mode, and no NAV or HDG mode.

ACTUALLY, on the small planes I used to use my knees when I wanted to eat my lunch. ...........to control the plane!!!!......not to eat the food!!   On BASIC two axis or single axis auto pilots, a wing leveler or leveler and HDG may be all you have. Even just a leveler makes life a lot easier!

Beats using your knees..................or a broomstick