An aircraft on approach above the Glideslope would be receiving what type of amplitude modulation?

An aircraft on approach above the Glideslope would be receiving what type of amplitude modulation?

• A. 45 Hz
• B. 60 Hz
• C. 90 Hz
• D. 120 Hz

Answer: (C)

When an aircraft is on approach and positioned above the Glideslope, it is receiving a specific type of amplitude modulation related to its navigation aids, specifically the Instrument Landing System (ILS). The ILS provides guidance in both the lateral (localizer) and vertical (glideslope) dimensions. The Glideslope signal is modulated at a frequency of 90 Hz. When an aircraft is above the Glideslope, it will receive more of the upper side of the modulation, which is typically interpreted by the avionics to indicate that the aircraft is in a high position relative to the desired descent path. This amplitude modulation frequency is critical for ensuring that pilots can adjust their descent to remain on the correct glideslope path, thereby achieving a safe and accurate landing. Understanding this aspect of avionics shows the importance of signal frequency in aircraft navigation systems. The other frequencies listed do not correlate with the Glideslope modulation, further solidifying that 90 Hz is the correct response for this specific scenario.

When an aircraft is on approach and positioned above the Glideslope, it is receiving a specific type of amplitude modulation related to its navigation aids, specifically the Instrument Landing System (ILS). The ILS provides guidance in both the lateral (localizer) and vertical (glideslope) dimensions.

The Glideslope signal is modulated at a frequency of 90 Hz. When an aircraft is above the Glideslope, it will receive more of the upper side of the modulation, which is typically interpreted by the avionics to indicate that the aircraft is in a high position relative to the desired descent path.

This amplitude modulation frequency is critical for ensuring that pilots can adjust their descent to remain on the correct glideslope path, thereby achieving a safe and accurate landing. Understanding this aspect of avionics shows the importance of signal frequency in aircraft navigation systems. The other frequencies listed do not correlate with the Glideslope modulation, further solidifying that 90 Hz is the correct response for this specific scenario.