FAA Instrument Rating Written Practice Test

When faced with a malfunctioning electronic glide slope during an Instrument Landing System (ILS) approach, the appropriate response is to request a localizer approach. This is because the localizer provides lateral guidance, while the glide slope provides vertical guidance. By switching to a localizer approach, the pilot is effectively acknowledging that the vertical component is not reliable due to the glide slope failure.

Additionally, since the VASI is visible, the pilot can then utilize it visually to maintain the correct descent path. However, it is crucial to adhere to the minimum descent altitude (MDA) set by the localizer approach procedure, while also being cautious about descending below the VASI reading if necessary. This ensures that the approach remains safe and compliant with established procedures.

Continuing the approach using the VASI glide slope, as mentioned in the other choices, is not advisable because the VASI is not an official navigational aid for ILS, and relying solely on it could lead to suboptimal decision-making. Aborting the approach or descending immediately to the localizer Decision Height (DH) without proper procedure can also pose safety risks and is not a correct course of action without verifying conditions.

In summary, the recommendation to request a localizer approach while being mindful of