PLT277: ILS Marker Beacons
What code PLT277 covers, why the FAA tests it, and how to study ILS Marker Beacons before your checkride.
Recall ILS - marker beacon / indicator lights / codes
What this means for your checkride
Marker beacons mark fixed points along an ILS: the outer marker (blue light, low tone, dashes) near the final approach fix, and the middle marker (amber light, higher tone, alternating dots and dashes) near decision height. They tell the pilot where they are on the approach by light and sound.
Marker beacons confirm position on the approach, so the FAA tests their light colors, tones, and where each one sits.
Pilots confuse the outer and middle markers. The outer marker is blue with a steady low tone near the FAF; the middle marker is amber with a higher, alternating tone near decision height.
Where to study it
A code on your test report is an area of deficiency. An authorized instructor must review it with you and endorse that review before you take the practical test, and the examiner may revisit it during the oral. Study it until you can explain it out loud, not just recognize the answer.