AFS 4500 and TruTrak Vizion questions
When it states you must intercept the glide slope from below, it means the glide slope is above you (the glide slope is coming from the airport up at an angle, usually 3 deg).
Prior to reaching the approach fix (AF) you have already armed the AP and have loaded your approach either to an IAF or Vectors To and are using the heading bug to steer your plane as ATC is directing you for vectors. The AP will be in either NAV mode or heading/track mode with NAV highlighted on your efis AP screen which means when the you get close to the AF the AP will automatically transition from Heading/Track mode to NAV mode. So if for example the approach fix is 3500', you are at 3500' prior to reaching the AF, the glide slope is above you and you will intercept it when you reach the AF. The vertical altitude on the AP will arm automatically and bring you down the gs.
Let's say you are instead of 3500' but at 3600' and are 3 or 5 miles from the AF, the glide slope will still be above you and you will intercept the glide slope prior to reaching the AF, the AP's vertical altitude will still arm and bring you down the glide slope. I believe the AP requires you to be below the glide slope for 5-7 sec prior to intercepting the glide slope for the vertical altitude to arm.
Hope this helps. The best way to fully understand is go out a fly approaches under VFR. You don't need ATC to shoot approaches under VFR. Remember for your efis to transition from heading mode to NAV mode you must be 30 deg or less from intercepting course line. If not you will blow right through the course line. Also you should be 3 to 5 miles from the FAF upon intercepting the course line for the AP to properly arm assuming you are using vectors to the FAF.
RV-6A IO-320 FP sold
RV-7 IO-370 Titan nearing completion
Donated 2018 and continue annually
Last edited by FireMedic_2009 : 05-18-2020 at 11:58 AM.