Which IFF mode is NOT included in the identification friend or foe (IFF) modes?

The identification friend or foe (IFF) system is a vital component in air defense, allowing military and civilian aircraft to distinguish between friendly forces and adversaries. The various modes within IFF serve specific purposes and functionalities.

Mode 1 and Mode 3A are among the standard IFF modes used for identification. Mode 1 was traditionally used for military identification and offers a limited response capability. Mode 3A is often utilized in civilian air traffic control and is a common mode found in transponder systems, providing information that helps air traffic controllers identify aircraft in their airspace.

Mode 4 is designed for secure military use and employs encrypted responses to ensure that the identity of the responding asset can be verified as friendly, further enhancing operational security.

In contrast, Mode 6 is not a conventional IFF mode; rather, it refers to a more advanced data link for real-time identification and situational awareness. While it is a key aspect of military identification systems, it does not fall under the specific classifications typically used within traditional IFF operations.

Thus, the correct answer, Mode 6, indicates it is not included in the traditional IFF modes, which focus primarily on Modes 1, 3A, and 4 for their operations.