Two waypoints after activating FPL on approach

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   I’ve noticed this behavior for some time, but was asked a question about it today and didn’t know the answer.

I’m flying a flight plan to a destination airport. Prior to arriving, I add via the PROC key an RNAV approach with an appropriate IAF. I continue to navigate normally, with my next waypoint active, and then a “fence” followed by the first segment of the approach. I have the soft key “activate approach” available.

If I activate the approach, the FPL removes the “fence”, and the resulting flight plan has the current waypoint, followed by the IAF. It then shows the approach, with the first waypoint repeated. The second copy of the waypoint has an altitude restriction, while the first does not.

If I select the second waypoint and activate it, the IFD changes into GPS->LNAV+V. If I do not, when I reach this waypoint, the IFD cycles to the next waypoint in the approach, and the GPS->LNAV+V appears.

Why, when I activate the approach, does it not just sequence to the IAF and arm the GPS->LNAV+V?

Thanks!

P.S. The IAF in this example has an altitude higher than I’m flying at. I don’t know if this is related somehow, just providing it for complete information. 

Edited by Melohn - 21 hours 35 minutes ago at 7:38pm

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Melohn Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 11 Dec 2013 Location: PHNL Status: Offline Points: 146	Post Options Post Reply Quote Melohn Report Post Thanks(0) Quote Reply Topic: Two waypoints after activating FPL on approach Posted: 21 hours 41 minutes ago at 7:32pm
	I’ve noticed this behavior for some time, but was asked a question about it today and didn’t know the answer. I’m flying a flight plan to a destination airport. Prior to arriving, I add via the PROC key an RNAV approach with an appropriate IAF. I continue to navigate normally, with my next waypoint active, and then a “fence” followed by the first segment of the approach. I have the soft key “activate approach” available. If I activate the approach, the FPL removes the “fence”, and the resulting flight plan has the current waypoint, followed by the IAF. It then shows the approach, with the first waypoint repeated. The second copy of the waypoint has an altitude restriction, while the first does not. If I select the second waypoint and activate it, the IFD changes into GPS->LNAV+V. If I do not, when I reach this waypoint, the IFD cycles to the next waypoint in the approach, and the GPS->LNAV+V appears. Why, when I activate the approach, does it not just sequence to the IAF and arm the GPS->LNAV+V? Thanks! P.S. The IAF in this example has an altitude higher than I’m flying at. I don’t know if this is related somehow, just providing it for complete information. Edited by Melohn - 21 hours 35 minutes ago at 7:38pm

midlifeflyer Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 21 Aug 2021 Location: NC Status: Online Points: 10	Post Options Post Reply Quote midlifeflyer Report Post Thanks(0) Quote Reply Posted: 9 hours 11 minutes ago at 8:02am
	I can’t answer the second part without knowing the approach and where you were coming from so it can be reproduced in the simulator. But as a general rule, “Activate (capital A) the Approach” will take you to whatever you chose as your initial transition when you first loaded the approach, which is why many don’t ever touch it. It's not quite the same as what Garmin does in it's units, but it's problematic enough that I choose to go Direct to the appropriate fix or activate the appropriate leg as the means of activating (lower case a) the approach. Edited by midlifeflyer - 7 hours 53 minutes ago at 9:20am

Melohn Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 11 Dec 2013 Location: PHNL Status: Offline Points: 146	Post Options Post Reply Quote Melohn Report Post Thanks(0) Quote Reply Posted: 1 hour 46 minutes ago at 3:27pm
	I’m pretty sure this occurs on all approaches when you follow the steps I mentioned above. If you want to reproduce it, start at origin PHNL, add a waypoint like CKH, then add PHNL as the destination. When you add the approach via PROC (say VOR-A as an example), and choose as IAF (HAUNA as an example), you’ll see a discontinuity as expected between CKH and HAUNA. You’ll also see the activate approach soft key come up. If you activate the approach at this point, there will be two HAUNA waypoints added, one that draws the track between CKH and HAUNA, and the other the first waypoint in the approach, which includes altitude restrictions, and arms the GPS->VLOC in the top right corner. I’m not suggesting this isn’t doing the right thing as far as navigating goes, I just don’t understand why two waypoints of the same name are added to the flight plan. Edited by Melohn - 1 hour 37 minutes ago at 3:36pm

dmtidler Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 12 Feb 2016 Location: USA Status: Offline Points: 622	Post Options Post Reply Quote dmtidler Report Post Thanks(0) Quote Reply Posted: 25 minutes ago at 4:48pm
	I don't recall the reasons for the change; however, double waypoints in this situation was an intentional change Avidyne made when AviOS 10.3 was released. Prior to AviOS 10.3, double waypoints like this did not exist.

midlifeflyer Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 21 Aug 2021 Location: NC Status: Online Points: 10	Post Options Post Reply Quote midlifeflyer Report Post Thanks(0) Quote Reply Posted: 11 minutes ago at 5:02pm
	I don’t understand the logic of the double waypoint. Maybe something as simple as an unacceptable angle. But I do see it as a reason not to “Activate Approach” unnecessarily. If instead, you go Direct HAUNA and ignore the discontinuity, it all works. If you’re looking for the “why” or a different solution, sorry, I can’t help.