ILS Actions RNAV

The ILSILS —Instrument Landing System creates two "lobes" of radiation for both localiser and glideslope, modulated at 90 and 150Hz.

  • For the localiser, the 90Hz lobe is to your left as you approach, so if you have more of that lobe you have to fly to the right (as you are too far left). The opposite is true for the 150Hz lobe.
  • For the glideslope, the 90Hz lobe is above the glideslope, so if you have more 90Hz in glideslope you have to fly down, and vice versa for the 150Hz.

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You are flying an ILSILS —Instrument Landing System approach and you receive more of the 90 Hz wave in the localiser and more of the 150 Hz wave in the glideslope. What are your actions?