What is the minimum distance to maintain in front of an engine inlet under normal conditions?

The correct choice indicates that the minimum distance to maintain in front of an engine inlet under normal conditions is 10 feet. This distance is crucial for ensuring safety around aircraft, particularly in relation to jet engines, which can create significant airflow and suction. Maintaining this distance helps to protect personnel from hazards such as being struck by debris or being caught in the engine blast, which can be powerful and dangerous.

The established distance provides a buffer zone where personnel and equipment can remain safe while allowing the engines to operate without interference. Understanding and adhering to this guideline is an essential part of ground operations and safety protocols in aviation.