Question

What is the frequency used by the glide slope transmitter?

(a) VHF

(b) UHF

(c) MF

(d) LF

This question was posed to me in an international level competition.

My question is from ILS/MLS Coupled Landing System and Automatic Landing topic in division Autopilots and Flight Management Systems of Avionics

Answer 1

Correct option is (b) UHF

Explanation: The glide slope or glide path transmission is at UHF frequencies from 329.3 to 335 MHz frequency and provides information to the aircraft as to whether it is flying above or below the defined descent path of nominally 2.5◦, for the airport concerned. The glide slope receiver output is proportional to the angular deviation γV, of the aircraft from the center of the glide slope beam which in turn corresponds with the preferred descent path.