Which type of radio serves as a secondary communication method for flight control?

The correct answer is that LOS Radio serves as a secondary communication method for flight control. LOS, or Line of Sight Radio, operates within a defined range typically up to several miles, relying on a direct line of sight between the transmitting and receiving antennas. This type of radio is particularly useful in contexts where primary communication channels might be compromised or where a backup system is essential.

LOS Radio is effective for flight control because it provides reliable communication without the need for satellite access or extensive infrastructure, which can be vital during specific operational scenarios such as close-range operations or when other communication systems are unavailable due to interference or malfunction.

In contrast, the other types of radios listed have different primary functions or operating conditions. VHF Radio is commonly used for voice communication over relatively long distances but is not specifically aligned with secondary communication for flight control in all scenarios. X-band Radio primarily focuses on radar and is not generally used for voice communication. SATCOM Radio allows for global communication but may not serve effectively as a secondary communication method due to reliance on satellite connectivity, which can experience latency and potential vulnerabilities.