Which example is considered a typical non-combat PTSD stressor?

Witnessing a plane crash is considered a typical non-combat PTSD stressor because it involves exposure to a traumatic event that is not directly related to combat. Non-combat stressors can include a wide range of experiences that elicit strong emotional responses and may lead to the development of post-traumatic stress disorder (PTSD). Such events may include accidents, natural disasters, or sudden traumatic incidents where the individual is not actively engaged in combat or warfare.

In contrast, the other scenarios provided—engaging in combat with the enemy, serving in a war zone, and conducting surveillance missions—are all directly related to combat or military operations, making them combat-related stressors. These experiences often involve direct threats to life or exposure to the horrors of warfare, which can also lead to PTSD but fall into a different category than non-combat stressors. Therefore, witnessing a plane crash stands out as a distinct example of a traumatic event that can still profoundly impact an individual's mental health without the direct involvement in combat.