I've practiced tracking an VOR radial in VFR conditions with a CFI. We tuned and identified the VOR, muted the Morse code, set the OBS, and then followed the CDI needle indications. I have not used a VOR that had HIWAS or flight service. For me, there is some confusion on my part of if the Morse code identification and audio are separate encoded channels in the VOR signal that the radio lets you select between, or if the "PULL IDENT"* button on the radio is unmuting all audio.

My understanding is that ILS approaches (laterally/horizontally) are like a VOR, but with a much narrower width of coverage (and much greater angular sensitivity) than a VOR.

Working from that, I assume that when you use an ILS, you tune it, make sure your audio panel is configured to let you hear audio from the Nav radio you are using, and then you pull the "PULL IDENT" knob, turn it up if needed, and listen for the Morse code. Assuming that you get the correct code, would you then push the "PULL IDENT" knob to silence the Morse code? Or continue to listen to it for the whole approach? If you do mute the identification audio, are you then also muting the marker beacon audio? Or is that a different system entirely? Do pilots listen for marker beacon Morse code and pick that out from the identification Morse code, while hand flying an ILS approach?

*See the diagram on https://www.hodgeflightservices.com/wp-content/uploads/2017/11/Bendix-King-KX-155A-NAV-COM-Radio-Manual.pdf page 3 ("S1-5" on the PDF half pages), knob I'm talking about is labeled as number 8.


1 Answer 1


This depends on your aircrafts equipment but the VOR/LOC/ILS receiver is independent of the marker beacon receiver and monitored differently. The morse code identifier of the VOR/LOC/ILS unit tells you it is operating correctly and can be used while the morse code identification of a Marker Beacon tells you "you are overflying it".

The marker beacon audio comes over a the marker beacon receiver not the VOR frequency. The aircraft I fly all have Garmin audio panels which have MKR button (and a marker beacon receiver) that is used to select the marker beacon audio mode. This is independent of the NAV1 and NAV2 radio monitoring capabilities which bus the output of the nav radios to the headsets. Muting NAV1 or NAV2 does not effect the MKR setting.

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Most of the audio panels I have encountered also have lighted displays for the marker beacons. The O M I will illuminate when the beacons are overflown. On the Garmin units this occurs regardless of the audio setting.

In all cases, the marker beacon lamps operate independently of any audio selection and cannot be turned off. The GMA 340 can drive external marker lamps if required.

FWIW the marker beacon system is being phased out in favor of GPS measured distance.

To answer the direct scenario

  • The radio is typically muted after the morse code identifier is received
    • Some of the newer glass systems will even display an ID on the panel when the morse code signal is received from the station so you dont need to identify it using the tones manually any more.
  • This does not impact the marker beacon audio or reception
  • You may choose to leave the nav audio on during the approach to confirm the system works for the whole approach but they are quite static-y and may get distracting if left on.
  • Some pilots will listen for Marker Beacon audio, I prefer the lights.

Note: The Pull Ident mode on most radios will only work if the appropriate NAV is selected on the audio panel as well but that will depend on your setup.

Saftey Note: With the way the modern IFR system works (at least here in the US) I would be very hesitant to fly an aircraft in actual IMC that did not have an IFR certified GPS unit which would make marker beacons more or less obsolete.


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