What is the normal range of a glideslope in an ILS approach?

The normal range for a glideslope in an Instrument Landing System (ILS) approach is approximately 10 nautical miles. The glideslope provides vertical guidance to pilots during the final approach phase, typically operating at an angle of about 3 degrees, which leads to the runway. This range is standardized to help ensure that aircraft have appropriate lateral and vertical guidance as they approach the runway from a sufficient distance, allowing for safe descent and accuracy during landing.

A range of 10 nautical miles aligns with the operational standards set by aviation authorities and facilitates a smooth transition for pilots entering the approach phase. Other ranges specified (like 5, 15, or 20 nautical miles) do not reflect the commonly accepted operational limits for glideslope guidance in standard ILS approaches.