Final answer:
The flashing "ILS" indication during an ILS approach indicates a problem with the Instrument Landing System.
Step-by-step explanation:
The flashing "ILS" indication during an ILS approach indicates a problem with the Instrument Landing System. This system provides lateral and vertical guidance to help pilots accurately align with the runway and descend to a safe landing. The flashing amber indication suggests that there is a fault or some deviation from normal operation in the ILS system, and pilots should exercise caution and consult with air traffic control for further guidance.