Certified Flight Instructor Instrument Oral Test 2025 – Complete Practice Guide

In the scenario of a glideslope failure during an Instrument Landing System (ILS) approach, using the Vertical Glide Slope Indicator (VGSI) serves as an effective alternative for vertical guidance. The VGSI provides pilots with visual cues on the correct approach path, indicating whether they are above, below, or on the desired glide path. This visual guidance is crucial for maintaining a safe approach and landing, especially when the electronic glideslope signal is not operational.

While the ILS localizer provides lateral guidance, it does not offer vertical information, making it insufficient as a substitute for glideslope guidance. The Flight Director can assist pilots in maintaining correct attitude and altitude but relies on the existing vertical guidance to function properly. Similarly, an Autoland system requires both lateral and vertical guidance to execute a safe landing automatically; without the glideslope functioning, the system would not provide the necessary vertical inputs. In this case, relying on the VGSI ensures that pilots can successfully manage their descent and approach safely, even in the absence of the electronic vertical guidance usually provided by the glideslope.