While experiencing a radio failure, what altitude should a pilot maintain for three minutes?

When a pilot experiences a radio failure, they should maintain the last assigned altitude for three minutes as a best practice. This altitude is where air traffic control had previously instructed the pilot to operate, which ensures that the aircraft remains within the air traffic system and can be tracked during the failure. By staying at this altitude, the pilot effectively communicates through their actions, indicating they are following the last received instructions while allowing time for any potential re-establishment of communications.

Additionally, maintaining this altitude helps to avoid any confusion that might arise from making abrupt altitude changes, which could lead to potential conflicts with other aircraft or air traffic control. The three-minute period serves not only as an acknowledgment of the last commands given but also provides a buffer to determine if the radio failure can be resolved or if further actions are needed.

Other options, such as current altitude, emergency level altitude, or minimum safe altitude, do not align with standard procedures in this scenario, as they could complicate situational awareness and response from air traffic services.