How many lights are required when using the NATO T marking?

The use of the NATO T marking for helicopter landing zones requires a specific number of lights to ensure visibility and effective communication to pilots and crews approaching landings zones. The correct answer indicates that five lights are required. This configuration helps in creating a clear visual representation of the intended landing zone for incoming helicopters.

The NATO T marking is essential in combat and emergency situations, providing an unambiguous signal to the pilots. The five lights—three in a horizontal line and two attached vertically—create the "T" shape that serves as guidance for landing. This standardized lighting system enhances safety and operational efficiency by making the landing zone easily recognizable from the air, even in low visibility conditions.

In contrast, other configurations involving different numbers of lights do not meet the established protocols for NATO T markings and wouldn't provide the necessary clarity for pilots during landings. This is why the specified number of five lights is critical when employing this method in an HLZ scenario.