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Back course localizer approaches

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I have been practicing the back course localizer approach to runway 2L in Santa Ana (SNA) using my PC simulator. I switch the CDI from GPS to VLOC on the simulated Garmin 430 just before getting to MINOE (IAF/IF). I get reverse needle indications on the separate VOR/LOC gauge and normal heading indications on the Garmin 430 screen (Page 1 of NAV).  My understanding is that the heading indications on the Garmin 430 screen are GPS based (instead of ‘corrected’ BC localizer indications).  Consequently, in order to be legal I am supposed to disregard these indications and fly the approach using the separate VOR/LOC gauge.

Could somebody please answer the following questions:

  • Is my PC simulator representing correctly BC approaches using the Garmin 430 and the separate VOR/LOC gauge?
  • Are my above statements about the heading indications in the G 430 correct?
  • Could I use the GPS to fly to NEWPO (the final fix) and switch the CDI to VLOC there?
  • Should I have a DME in the plane to fly this approach, assuming that I don’t want to time the approach, since the Garmin distance information is based on GPS and GPS is not considered legal to fly a localizer approach?

Thanks

1 Answers



  1. Russ Roslewski on Oct 06, 2016

    You have most of it right, with a few minor corrections.

    > Is my PC simulator representing correctly BC approaches using the Garmin 430 and the separate VOR/LOC gauge?

    Yes.

    > Are my above statements about the heading indications in the G 430 correct?

    I think you mean “course deviation indications”, but yes.

    >Could I use the GPS to fly to NEWPO (the final fix) and switch the CDI to VLOC there?

    No, actually. If it was a VOR approach, the answer would be yes, but according to the AC on GPS substitutions, you must use actual LOC guidance for all guidance on a LOC, or LOC-BC course: http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_90-108_Chg_1.pdf

    Of course, you can always “monitor” the GPS data on your secondary display (the GPS itself) while officially navigating using the LOC-BC data on your primary display.

    >Should I have a DME in the plane to fly this approach, assuming that I don’t want to time the approach, since the Garmin distance information is based on GPS and GPS is not considered legal to fly a localizer approach?

    DME not needed, GPS is substitutable (new word?) for DME, see the above AC.

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