Which of the following is NOT a Masking/Unmasking technique?

Masking and unmasking techniques are critical in terrain flight operations to enhance aircraft survivability by using the natural terrain to shield from enemy observation and fire. Each technique is used to maintain a low profile while navigating the environment.

The correct answer identifies "Horizontal" as not being recognized as a standard masking/unmasking technique. While horizontal movement can imply staying level with terrain, it is generally encompassed within the other techniques rather than identified as a standalone practice.

Vertical masking refers to using the changes in elevation to conceal the aircraft from enemy eyes, while lateral and in-flight techniques relate to strategies for effectively moving through terrain without exposing the aircraft to threats. Each of these is specifically designed to enhance stealth and improve the effectiveness of terrain flight operations.

Understanding these definitions is essential for pilots and operators to effectively plan and execute missions while minimizing exposure to hostile engagements.