Final answer:
In case of radio failure in an aircraft, the pilot should follow the published procedures for landing without radio communication, including observing light signals and using transponder code 7600.
Step-by-step explanation:
If an aircraft's radio fails, the correct procedure when planning to land at a controlled airport is to follow the published procedures for landing without radio communication. Using a mobile phone could interfere with critical frequencies, as both airplanes in flight and medical equipment in hospitals may be affected by the 1.9 GHz frequency used by phones. The best approach is to follow visual flight rules (VFR) or instrument flight rules (IFR) non-verbal communication protocols, which might include observing light signals from the tower, squawking 7600 on the transponder to indicate a radio communication failure, or following standard patterns of traffic while watching for light gun signals from the control tower. While circling the airport might seem like an option, it's not recommended without proper coordination as it could interfere with other traffic. Attempting to fix the issue mid-air should not take precedence over maintaining safe flight operations.