DME Arc with GTN 650 Xi and GFC500 ?

[hubcap]

I haven’t been able to try out the new avionics on a DME Arc approach. Was wondering if any of the gurus have any guidance? If I am not mistaken, it would have to use GPS for the DME Arc, and then switch over to ILS when goin inbound. 
 

Any special button pushing required for this approach?

[kortopates]

yes, and you can intercept anywhere by activating the leg of the arc - you don’t even have to start at an iaf.


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[PeteMc]

48 minutes ago, hubcap said:

it would have to use GPS for the DME Arc, and then switch over to ILS when goin inbound. 

Your GTN should actually automatically switch to the ILS/VLOC.  I haven't done a DME Arc since pre GPS and I remember that the manual says there are some approaches where the GTN won't auto switch, but I don't see why it wouldn't on an Arc.  So when you do fly one, let it go the first time and see if it switches over on its own. 

 

[TCC]

Your GTN should actually automatically switch to the ILS/VLOC.  I haven't done a DME Arc since pre GPS and I remember that the manual says there are some approaches where the GTN won't auto switch, but I don't see why it wouldn't on an Arc.  So when you do fly one, let it go the first time and see if it switches over on its own. 
 

Just flew one today, the Kelly Field ILS 16 behind a GTN750. At the lead radial, the GTN sequences to intercept the FAC beyond the IF. Once established on the FAC, the auto switch to VLOC occurred with about 4NM to go to FAF/GS intercept.

[Marc_B]

If you have your GTN set to auto switch CDI then you’ll fly the DME arc inbound using GPS. The auto switch will occur within 1.2 nm (see pic)from localizer course. But you have to make sure you have the ILS freq tuned/active or it won’t switch. When you load the procedure in the GTN it loads ILS freq in standby. 
Also, if you don’t have APR armed before the CDI auto switches, you’ll revert to roll and pitch mode and could blow through the final approach course if you don’t catch it. 
it’s pretty seemless with a few gotchas so I’d definitely try to fly one in good conditions first. 

[midlifeflyer]

8 hours ago, Marc_B said:

If you have your GTN set to auto switch CDI then you’ll fly the DME arc inbound using GPS. The auto switch will occur within 1.2 nm (see pic)from localizer course. But you have to make sure you have the ILS freq tuned/active or it won’t switch. When you load the procedure in the GTN it loads ILS freq in standby. 
Also, if you don’t have APR armed before the CDI auto switches, you’ll revert to roll and pitch mode and could blow through the final approach course if you don’t catch it. 
it’s pretty seemless with a few gotchas so I’d definitely try to fly one in good conditions first. 

Perfect. 
 

Basically works like all the other VLOC approaches. GPS until the FAF becomes the active waypoint, then switches. 

And yes, absolutely ensure that you move the ground based navaid frequency to active and that it has been identified. That's a common error in these auto-switching days. You see the gotcha especially with the 650 where you have to manually switch to NAV to even see the loaded frequencies. 

It was fun the other day when the localizer was OTS but not NOTAM'd. Pilot didn't confirm ID.
 

[RoundTwo]

12 hours ago, hubcap said:

I haven’t been able to try out the new avionics on a DME Arc approach. Was wondering if any of the gurus have any guidance? If I am not mistaken, it would have to use GPS for the DME Arc, and then switch over to ILS when goin inbound. 
 

Any special button pushing required for this approach?

I had no idea that my whizbang stuff in the airplane would do that. This is great information. 

[midlifeflyer]

4 hours ago, RoundTwo said:

I had no idea that my whizbang stuff in the airplane would do that. This is great information. 

Depends how much whizbang you have. Even an older GNS will prompt you around the arc.  Whether the autopilot will follow it depends on whether you have GPSS. The GFC500 will definitely do it. 

OTOH, it's practicality might be minimal unless for some reason you prefer the extra steps of monitoring the switching involved in a DME arc to the relative simplicity of RNAV.