While holding for an ILS approach due to a radio communication failure, which procedure should be followed?

The recommended procedure when holding for an ILS approach due to a radio communication failure is to squawk 7600, which indicates a communication failure. This allows air traffic control (ATC) and other aircraft to be aware of your situation. Planning to begin the approach at the advised time is crucial because it helps maintain the sequence and flow of traffic in the airspace, ensuring that you are following the necessary protocols despite the communication failure.

In the context of ILS approaches, it is essential to adhere to timing and procedures, especially when ATC has given a specific clearance or holding pattern prior to the communication failure. This approach ensures that safety and orderliness are maintained in the airspace, and it aligns with standard aviation procedures for communication failures.

Squawking 7700 indicates an emergency, which is not the appropriate response if the situation is strictly a radio communication failure. Similarly, squawking 7500 signifies a hijacking, which is not relevant in this context. Waiting for clearance in this case could lead to unnecessary delays and potential conflicts with traffic, which is why squawking 7600 and following the advised time for the approach is the suitable course of action.