Using GPS to ID FAF for LOC

[kontiki]

All,
I'm trying to figure out how to set the LOC timer as a backup on an ILS approach in a G1000 equipped aircraft.
I'm looking at the Millington, TN ILS or LOC RWY 22 at KNQA approach.
The FAF (PIRGE) is shown on the chart as I-NQA DME 6.5 and also identified as the fix PIRGE.
Can I legally just activate the ILS approach in the GPS, fly the ILS Glide Slope and set the LOC timer when I sequence to PIRGE?
Or, should I instead go without the ILS assistance on the MFD and set GPS direct to I-NQA to use it as a DME?
I know I'm splitting hairs here, but I had to fly something like this over on my check ride, because of this, and it frustrates me that I can't remember exactly how it goes.

 

[John Collins]

Why time it at all. The localizer MAP is at the threshold and it should be the waypoint RW22. On the other hand if I were to lose the GS on the approach, I would miss the approach and re-brief for the localizer option or another approach such as the RNAV (GPS) 22 with the LPV.

 

[poadeleted20]

Why time it at all.

Two reasons:

1. Keeps you in the habit of hacking the clock at the FAF on LOC approaches so next time you fly without a GPS, you'll remember to do it.
2. Provides a backup in case the RAIM warning activates halfway through the LOC approach.

So, as you approach the FAF, bring up the timer window, and as you cross it, do your 5 T's including starting the timer.

As for doing this on an ILS approach, the odds of losing both GS and GPS are small enough that it's not really necessary in a G1000 system. However, for non-GPS aircraft, I still recommend hitting the clock crossing the FAF so you have a backup to tell you when you've reached the MAP and should start any required turn for the missed approach if the GS fails during the final segment. You can certainly abandon the approach and start the climb before the MAP if the GS fails and you don't want to revert to LOC, but you still have to know when to start any required post-MAP turn, and with neither clock nor GPS, you won't know when to do that.

 

[midlifeflyer]

No reason you can't load the approach and identify the FAF using that.