VOR Backcourse annunciator light

Discussion in 'Avionics and Upgrades' started by 2nd505th, Feb 22, 2020.

  1. 2nd505th

    2nd505th Pre-Flight

    Joined:
    Apr 11, 2018
    Messages:
    35
    Display Name:

    Display name:
    2nd505th
    Is anyone familiar with the backcourse light on a IN-385AC VOR? After studying the wiring I came to the following guess/assumption which may be wrong.

    You need to manually via a switch activate a relay which reverses wiring to the VOR's pointer in/out connections and causes the vertical pointer to act opposite of the way it normally operates.

    In short my guess is it requires the manual flip of a switch?

    Any expertise/familiarity is appreciated.
     
    Last edited: Feb 22, 2020
  2. Plano Pilot

    Plano Pilot Pre-takeoff checklist

    Joined:
    Oct 24, 2016
    Messages:
    333
    Location:
    KADS
    Display Name:

    Display name:
    Plano Pilot
    You got my curiosity peaked and below is what I found. I think I flew an airplane years ago with that indicator.

    "12. BC LAMP - Amber light illuminates when the autopilot or reverse sense option is installed and the reverse sense switch or autopilot's back-course function is engaged; indicates course deviation pointer is reversed on selected receiver when tuned to a localizer frequency."

    Found on page 205 of:
    http://www.sq87-cap.org/uploads/Mission Resources/7304N_POH/C206_POH_GenericSearchable.pdf
     
  3. PPC1052

    PPC1052 En-Route

    Joined:
    Feb 2, 2012
    Messages:
    4,636
    Display Name:

    Display name:
    PPC
    Yes. You push the back course button on the Nav-o-matic autopilot. I have such an animal in my 177B.