My airline's vertical navigation data isn't certified for use and is considered 'advisory' only. But, 90% of the time it provides highly accurate data.

Some instructors at my company contend that 'localizer recommended altitudes' are required to be used as the primary / only reference for a CANPA style continuous descent to our DDA (derived decision altitude) on localizer approaches.

I contend that any method chosen for a descent to DDA is purely technique and as long as our advisory VNAV data is backed up with other data & looks accurate, there's nothing wrong with using it.

Are localizer recommended altitudes regulatory in any way? Is it legal to use an 'advisory' Vnav data to fine-tune your descent from the FAF to DDA? Any links, references, or regulations you can point me to on the subject would also be greatly appreciated.

  • 4
    $\begingroup$ If you want to be pointed to regulations, please include which jurisdiction you are operating in (e.g. the tag faa-regulations) $\endgroup$
    – DeltaLima
    May 24, 2016 at 14:53
  • 1
    $\begingroup$ You might get a better response to this question if you not only add the jurisdiction (FAA?) but also post a specific approach plate that shows exactly what your question is about. $\endgroup$
    – Pondlife
    Oct 12, 2016 at 21:25

1 Answer 1


If your company uses CANPA (continuous descent) approaches, the whole point is using artificial VNAV on non-precision approaches where no vertical navigation is part of the approach. This involves determining a DDA, or derived decision altitude, based on the published minimums and some other criteria. Arrival at the DDA requires a go-around just like if you were arriving at a DA on a precision approach.

In defense of your point, if you aren't using any form of vertical navigation, one might argue that it's no longer a CANPA approach at all. How can be maintain a constant angle without vertical nav?

Then again, if you are flying the CRJ a localizer approach would involve having the Proline 4 in "green needles." Advisory VNAV only works in "white needles," so if they're saying you shouldn't use advisory VNAV on a localizer only approach that might be the reason. You can't.

In reference to the main question in the title, you can't use advisory VNAV "in lieu" of the published minimums or minimums derived from your company regulations, but if you want to use advisory VNAV to plan your descent to the appropriate minimums, that's okay unless specific language in the company manuals forbids it.


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