I am thinking of getting an MGL N16 VHF Nav radio with the MGL Vega V16 Control head. It has an interesting mode of operation (referred to as SCAN Mode) where the single receiver in the N16 rapidly switches back and forth between the primary and standby VHF frequencies. In this mode the Vega screen displays navigation information from both frequencies on the screen at the same time - (2 VORs, or a VOR and an ILS, for e.g.). Of course in this mode it is not on either frequency long enough to hear, or to decode the audible Morse code identifier, so the system does not send the audio to the intercom or display decoded ICAO call letters on the screen. With SCAN Mode off the Morse code from the one (primary) frequency is audible, and the screen shows the decoded 4-character identifier next to the frequency.

I was told (although I have not been able to locate a reference for this), that FARs require that you identify the Morse code identifier to legally use a VHF NAVAID signal for navigation.

So, although it is simple to turn the SCAN function on and off, do you need to have the Morse code identifier continuously, throughout the entire approach, to legally use a NAVAID for navigation? Or is it sufficient to do this once, on the initial portion of the approach, and then turn SCAN Mode on to concurrently monitor another NAVAID (like an airfield VOR while on an ILS approach)?

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    $\begingroup$ I was taught to continuously identify an NDB, because there is no other indication if the station is lost. A VOR or ILS will flag if the signal is lost, so I wasn't taught to continuously identify those. $\endgroup$ Commented Dec 7, 2021 at 18:00
  • $\begingroup$ Although there is no specific FAR requiring a pilot to tune and identify a navaid (vor, ils, etc.) prior to relying on it for navigation it's crucial that you do so for obvious safety of flight implications. In fact, not doing so would be contrary to the required skills specifically identified to be demonstrated in the Airman Certification Standards (for the instrument rating, and various other checks). So, you could be subject to a failure of a check ride for not turning and identifying the navaid prior to use. $\endgroup$
    – user22445
    Commented Dec 7, 2021 at 23:52
  • $\begingroup$ I have never heard it required that you listen to the Morse code, must less continuously. (I can't shut it off fast enough!) I know it is at least a best practice to ID a navaid, but personally I think it's overrated in terms of risk reduction. Really, what is the probability that a signal is broadcasting on the same frequency, in the same approximate location, putting out the same course info, that you might accidently lock onto because you failed to ID the code? I guess maybe I just don't understand well enough what specific scenario the practice is trying to prevent. Maybe a question? $\endgroup$ Commented Dec 8, 2021 at 2:53
  • $\begingroup$ I have not been able to find any clear Directive in the FARs myself. I was told this by someone on another forum.. They mention that this is required because sometimes, when VOR signal is out of service, being tested, or in error, the ident is used to signal this, so absence of an ident, or an inaccurate or "TEST" ident can be the only indication that the signal is unreliable. $\endgroup$ Commented Dec 8, 2021 at 15:03


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