Question 994Navigation General

The correct answer is D) ducting. Ducting is a phenomenon where radar signals can be bent or trapped within atmospheric layers, allowing them to travel much farther than normal. In this scenario, the large mountain 50 miles away is likely causing a temperature inversion, which can create a duct that traps the radar signals and reflects them back, creating a false target indication on the radar display. The other options are incorrect because sub-refraction refers to radar signals being bent downward, ionospheric skip waves involve signals being reflected from the ionosphere, and a submerged submarine would likely be detected as an actual target, not a false one.