What is the risk associated with unintentional movement after engine start?

Unintentional movement after engine start poses a significant risk of uncontrolled aircraft movement. This often occurs if the aircraft is not properly secured or if the pilot inadvertently applies thrust without full awareness of the surrounding environment. Such movement can lead to dangerous situations, including collisions with other aircraft, ground equipment, or obstacles on the airport ramp. Understanding and addressing this risk is crucial for maintaining safety during ground operations post engine start.

While passenger injury, aircraft damage, and ground equipment damage may also occur as consequences of uncontrolled movement, the core issue here is the lack of control over the aircraft itself, which makes option C the most pertinent to the question. By emphasizing the risk of uncontrolled movement, steps can be taken to mitigate this risk, such as ensuring all personnel are aware before engine start and that the aircraft is adequately secured.