Night vision devices (NVDs) mitigate risks in low visibility operations. However, NVDs also create new hazards. They contribute to different forms of spatial disorientation. Prolonged operation can also be associated with increasing levels of fatigue. The following pages describe how these problems can combine to exacerbate the demands of ‘brown-out’ landings when visibility is reduced by airborne particles, typically from helicopter downwash. We present a detailed case study of the loss of a Royal Air Force Puma on operational duty in Iraq during November 2007. Environmental conditions limited the effectiveness of NVDs. Contributory factors included organizational issues, such as a failure to follow Standard Operating Procedures, and a host of human factors concerns, including the loss of situation awareness across multiple teams. A companion paper in this conference shows that this was not a ‘one off’ accident. Both papers argue that there is an urgent need to go beyond existing military Boards of Inquiry if we are to protect the safety of military personnel. We must extend the scope of operational studies across the US and UK armed forced to ensure that we learn the lessons provided by the growing number of similar accidents, which stem from complex interactions between new technology and a range of environmental hazards, including ‘brown out’ conditions.