During the ILS RWY 13 procedure at DSM, what is the minimum altitude if the glide slope becomes inoperative?

In an Instrument Landing System (ILS) approach, the glide slope provides vertical guidance to assist pilots in maintaining the correct descent profile. However, if the glide slope becomes inoperative, pilots must adhere to specific procedures and altitude minima to ensure a safe approach to the runway.

For the ILS RWY 13 at DSM (Des Moines International Airport), the minimum altitude to maintain when the glide slope is inoperative is determined based on the published approach charts and guidance from the relevant aviation authorities. The minimum altitude that allows for a safe descent while visual references can be established at or near the threshold of the runway is crucial.

Choosing 1,380 feet indicates the altitude required to safely continue the approach without glide slope guidance. This altitude is established to ensure that the aircraft is at a safe height above the ground as it approaches the runway, accounting for the standard obstacle clearance and ensuring a safe transition to visual flight conditions as the aircraft interfaces with the runway environment.

This detail is essential for pilots to know in order to comply with safety regulations and ensure a successful landing in the absence of glide slope guidance.