In an ILS approach, what should you do if the glide slope becomes inoperative but you can still see the runway?

In the situation described, if the glide slope becomes inoperative during an ILS approach and the runway is visible, using the Visual Approach Slope Indicator (VASI) for guidance is a practical and safe alternative. The VASI provides visual descent path information, allowing you to maintain an appropriate glide path to the runway even without the electronic guidance of the glide slope. This method helps ensure a safe landing while still complying with visual approach requirements.

Proceeding with a visual approach, while a viable option in some scenarios, generally requires the approach to be transitioned to a standard visual approach rather than continuing an ILS approach. Similarly, cancelling the approach and flying a holding pattern or requesting to circle to land might create unnecessary delays or could complicate the flight operation, especially if you have visual runway contact. Therefore, relying on the VASI allows you to utilize available resources effectively while maintaining compliance with safety protocols.