Subelement K: K – Aircraft— Topic 70: Instrument Landing System (ILS)
Question 3-70K1
Element 3 (GROL)What is the frequency range of the localizer beam system used by aircraft to find the centerline of a runway during an Instrument Landing System (ILS) approach to an airport?
Explanation
The localizer beam system, a crucial part of an Instrument Landing System (ILS), provides pilots with horizontal guidance to align with the runway centerline. This system operates in the Very High Frequency (VHF) band.
The correct frequency range for ILS localizer transmissions is **108.10 MHz to 111.95 MHz**. This spectrum is specifically allocated for aviation navigation aids, distinct from general communication or other services.
Options A and C are incorrect because they specify frequencies in kilohertz (kHz), which are far too low (LF/MF band) for this type of precision navigation system. Option B, 329.15 MHz to 335.00 MHz, represents the frequency range used for the *glideslope* component of the ILS, which provides vertical guidance, not the localizer's horizontal guidance.
Related Questions
3-6A5 By what factor must the voltage measured in an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the average voltage value?3-6A6 What is the peak voltage at a common household electrical outlet?3-70K2 What is the frequency range of the marker beacon system used to indicate an aircraft's position during an Instrument Landing System (ILS) approach to an airport's runway?3-70K3 Which of the following is a required component of an Instrument Landing System (ILS)?3-70K4 What type of antenna is used in an aircraft’s Instrument Landing System (ILS) glideslope installation?