A British Royal Air Force (RAF) ground crew performs an engine parameter check on a GR-4 Tornado fighter-bomber aircraft that is parked on the tarmac at Eielson FB, Alaska (AK), during Exercise COOPERATIVE COPE THUNDER, the largest multinational air combat training exercise in the Pacific. This 15-day exercise simulates wartime combat conditions so that military personnel from 12-nations can sharpen their air fighting skills, exchange air operational tactics, and build closer relations with each other