Set altitudes for VNAV confusing

[RyderK]

Gday,

So I’ve noticed that some of the set altitudes for arrivals/approaches are a bit confusing and unnecessary. For instance I’ve seen an arrival into YSSY where it goes from 8000ft then to 9000ft then to 6000ft. What’s with the 9000ft? Also sometimes it will be set to 3000ft for a good 5-10NM which is a bit unrealistic for an aircraft to level out and fly 3000ft just before final. I’ve seen these on quite a few arrivals and approaches and so I’m wondering why they’re like this.

Thanks, Ryder.

[Thunderbolt]

This is all gathered data from a real-world source, NavBlue (Airbus), which Infinite Flight uses in-app. Whatever they have, IF has.

In this case, I’d edit the altitudes to your desired preference :)

[Kirby_D]

Yeah… The problem is that most STAR (and SID) altitudes as shown on the actual charts are stated as minimums or maximums but this is not implemented in IF (yet?) or is not provided by the service IF subscribes to.

So, the example you give matches the STAR chart BOREE 2A.
Waypoint BEKLO at or above 8000’
BEROW at or below 9000’
ZONKA/DIPPA at or above 6000’

So it is always important to check the arrival and approach altitudes for these occasional “awkard” inconsistencies. In this case, it would be simplest to delete the 9000’. For greatest realism you would look at the actual chart and decide for yourself how you want to comply with the mins and maxs. :-).

[RyderK]

Yeah that’s what I usually do. I’m not complaining, just curious as to why it was like that. Thanks for your replies.

[LordWizrak]

There are certain SIDs that lead you into the same approach, though different SIDs would have differing altitude restrictions. So it is entirely possible that one SID has an altitude restriction at 8000ft in the SID, while another one can have 14000ft as an example. That said, when paths converge to the approach path, they will all have to maintain the new altitude restriction, so say, for example its 9000ft. For those coming in at 8000ft, they can maintain altitude while those at 14000ft would have to descend to meet requirements for the approach.