The instrument landing system
9 min read
The parts
Localizer (VHF, 108.10–111.95 MHz on odd tenths, plus the .x5 channels above them, e.g. 109.30 and 109.35): lateral guidance along the runway centreline. Full-scale deflection is a few degrees either side (typically about 2.5°).
Glide path (UHF, about 329–335 MHz, paired with the localizer frequency): vertical guidance, normally 3°. Full scale is about ±0.7°.
Markers (75 MHz) on older installations: outer (blue), middle (amber), inner (white); often replaced by DME.
IN THIS LESSON
- Coverage
- False glide paths
- Protect the signal
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