Which of the following is a cause of FOD?

Facility deterioration is a significant cause of Foreign Object Damage (FOD) in aviation environments. Over time, facilities such as hangars, runways, and maintenance areas can suffer from wear and tear, which can lead to loose debris, broken equipment, or other foreign objects being present. These items can become dangerous if they find their way into engines or other sensitive areas of an aircraft, potentially causing significant damage.

While other factors like defective parts, inaccurate maintenance documentation, and improper fuel usage can certainly impact aircraft performance and safety, they do not directly relate to the concept of foreign objects that can lead to damage. Facility deterioration specifically addresses the physical environment where aircraft operations occur, making it a direct contributor to FOD incidents.