Not only in Korea, but also in other countries, most helicopter accidents occur at low altitude. Analysis on accidents data collected both in Korea and other countries has brought two conclusions. Firstly, helicopter operations during the night hours carries a high risk. Secondly, the most common cause of night hour operations is loss of control due to the flight illusion. As an operation relying on a night vision in particular has a very high accident hazard, accompanying instruments such as NVG are ought to be provided. Hence, a thorough preparation and inspection on missions for night forest fire extinguishing should be required and perfect guidelines/road maps and enough training programs for the operation should be provided before the engagement in missions.