What are the limitations on boarding while the engines are running?

The correct response highlights a crucial safety measure regarding boarding an aircraft while the engines are operational. When the engines are running, there are significant safety protocols in place, primarily to protect individuals from the dangerous jet blast generated by the aircraft.

Jet blast consists of high-velocity air being expelled from the engines, which can pose severe risks to anyone near the aircraft. Therefore, the requirement that all personnel must be clear of the jet blast area is essential to ensuring their safety. This protocol is designed to prevent accidents and injuries that could occur if someone were to inadvertently get too close to the powerful airflow.

Understanding this limitation ensures that safety is prioritized during the boarding process, maintaining a secure environment for both the crew and passengers. It reflects the airline industry's commitment to operational safety and awareness of the hazards associated with aircraft engines.