-While trying to fly the ILS 05 at KFWA with the G-1000 (Cirrus), after I was turned onto final and the OBS/NAV switched to the CDI/ILS, the aircraft never started down/captured the glideslope. Do I need to select the APR mode manually prior to glideslope interception? 

 

Terry

Basic ILS rules still apply for the G1000.

• The runway's ILS system must have a glideslope
• "APR" autopilot mode must be used
• Glideslope interception has to be from below the beam

OK so no auto approach mode even though the G1000 switches from NAV/GPS to the ILS/CDI display.

 

Terry

correct.

The CDI automatically changes from GPS to NAV1 as the final approach course is intercepted. You can then fly the approach manually, or in NAV mode (a localizer approach) or in APPR mode (a glideslope approach). The AP wont assume what you want to do.

In the real G1000 you can turn this feature off in the AUX pages.

As a side note the CDI does not change for VOR approaches.