Fly-by waypoint tolerance

[sarangan]

Recently I had an issue with the Garmin 430W that did not autosequence during an approach upon passing the "T" towards the FAF. Admittedly, I did turn a bit earlier than I should have, but not by much based on my GPS track. I was wondering if anyone knows the specific algorithm it uses for autosequencing around a flyby waypoint.

 

[BillTIZ]

I forget the exact number but 0.3 nm rings a bell. And even less if farther down the approach. Hint, don’t turn until the unit tells you to, then it will sequence.

 

[aterpster]

It should sequence at the bisector of the course change. If the heading won't intercept the next leg it might not sequence.

 

[luvflyin]

Just a guess here. There's that annunciation that tells you to expect to begin a turn in so many seconds. My guess is once it does that, you can begin the turn then rather than wait a few more seconds and it will sequence.