wayneda40
Line Up and Wait
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- Jul 31, 2017
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waynemcc
@asicer, indeed you're correct regarding the advisory, and my narrative at that point was I believe consistent... "As we approach the segment leading to the FAF, we transition to the green needles for the ILS". I believe that's also clear by the graphic that shows the segment leading to the FAF (GOYED-to-NAPPS) in dashed magenta ("reference only") and solid green. In fact, the navigators I noted in the video auto-switch from magenta to green needles on the segment leading to the FAF.At 3:33, you mention flying the GPS to the FAF (NAPPS in your example). However, AC 90-108 Section 8 says:
"An otherwise suitable RNAV system cannot be used for the following:... (c) Lateral Navigation on LOC-Based Courses. Lateral navigation on LOC-based courses
(including LOC back-course guidance) without reference to raw LOC data."
I take that to mean that the "green needle" data needs to be available prior to the FAF (HABUT-GOYED-NAPPS in your example) since those legs are based on the LOC.
Thoughts?
https://www.faa.gov/documentLibrary/media/Advisory_Circular/90-108.pdf
11.4.3 Unauthorized uses of RNAV Systems.
11.4.3.3 Localizer Course. To navigate a localizer final approach course.
Navigating the final approach segment (that segment from the final approach fix to the missed approach point) of an ILS, LOC, LOC-BC, LDA, SDF, MLS, TACAN approach, or any other type of approach not approved for GPS, is not authorized with GPS navigation guidance.
@John Collins, solid and up-to-date info… thanks!…
So if the AFMS doesn't require using the green needles until on the final approach segment of an ILS, then in spite of AC and AIM guidance to the contrary, that wording overrides the guidance.
You still have HABUT-GOYED in solid magenta and this course is defined by a LOC.@asicer, indeed you're correct regarding the reg, and my narrative at that point was I believe consistent with the reg... "As we approach the segment leading to the FAF, we transition to the green needles for the ILS". I believe that's also clear by the graphic that shows the segment leading to the FAF (GOYED-to-NAPPS) in dashed magenta ("reference only") and solid green. In fact, the navigators I noted in the video auto-switch from magenta to green needles on the segment leading to the FAF.
View attachment 103535
Thanks for watching and for checking in on this,
Wayne
I tend to choose the more conservative, which is to switch when the localizer comes alive according to AC 90-108. But I suppose at this point it's just splitting hairs. When AC 90-119 is finalized, I'll start switching at the FAF. And I look forward to doing so!What is in the AIM is not the most current thinking of the FAA but the guidance will take some time before it reflects what is part of the new draft AC. The wording in the AFMS was updated on the GNS series in 2013. Regardless, AFMS rules!
As John noted, with the G1000/GTN navigators the navigator does an auto-switch from magenta to green (and auto-sets and auto-swaps the ILS frequency!). One less chance for me to make an error (even though I must be the only person to have ever forgotten to switch to "VLOC" on a GNS430 ).You still have HABUT-GOYED in solid magenta and this course is defined by a LOC.
I tend to choose the more conservative, which is to switch when the localizer comes alive according to AC 90-108. But I suppose at this point it's just splitting hairs. When AC 90-119 is finalized, I'll start switching at the FAF. And I look forward to doing so!
You still have HABUT-GOYED in solid magenta and this course is defined by a LOC.
I tend to choose the more conservative, which is to switch when the localizer comes alive according to AC 90-108. But I suppose at this point it's just splitting hairs. When AC 90-119 is finalized, I'll start switching at the FAF. And I look forward to doing so!