Navigation Systems Flashcards

Which frequency range is allocated to VOR ground stations?

Answer: 108.00–117.95 MHz

VOR stations operate in the VHF band from 108.00 to 117.95 MHz.

How does a VOR receiver determine the aircraft's bearing from the station?

Answer: By comparing the phase of the 30 Hz reference and 30 Hz variable signals

Bearing equals the phase difference between the 30 Hz reference (FM on 9960 Hz subcarrier) and the 30 Hz variable (AM) signals.

DME equipment operates in which frequency band?

Answer: 962–1213 MHz

DME interrogations and replies use the UHF band between 962 and 1213 MHz.

A localizer receiver detects a predominance of the 90 Hz modulation tone. Where is the aircraft relative to the course?

Answer: Left of course, fly right

On the approach, 90 Hz predominates left of centerline, so the CDI commands a fly-right.

Glideslope transmitters operate in which band?

Answer: UHF 329.15–335.00 MHz

Glideslope frequencies are UHF, 329.15–335.00 MHz, and are paired with localizer frequencies.

The outer marker beacon is identified by which combination?

Answer: 400 Hz tone, blue light

The outer marker modulates 400 Hz dashes and illuminates the blue marker lamp.

An aircraft at 12,000 ft AGL passes directly over a DME station. What will the DME indicate approximately?

Answer: 2 NM

DME measures slant range, and 12,000 ft is about 2 nautical miles straight up.