On Friday 28th May 1982 the 2nd Battalion The Parachute Regiment was engaged in fierce fighting to take enemy positions in the area of Port Darwin. From dawn, Lieutenant Nunn, a Scout helicopter pilot, had supported the Battalion flying vital ammunition forward to the front line and had evacuated casualties heedless of enemy ground fire.

After flying continuously for three and a half hours, it was learnt that the Commanding Officer and others in Battalion Tactical Headquarters forward had been severely wounded. Lieutenant Nunn was tasked to evacuate these casualties collecting the Battalion Second in Command en route. However, five minutes after take off, suddenly and without prior warning, two Pucara aircraft appeared from the South and attacked the Scout with rockets and cannon fire. By great flying skill Lieutenant Nunn evaded the first attack but on the second his aircraft was hit and destroyed. Lieutenant Nunn was killed instantly and his aircrewman Sergeant Belcher was grievously wounded.

Lieutenant Nunn displayed exceptional courage, flying skill and complete devotion to duty in the face of the enemy. His achievements that day, supporting the Battalion, were exceptional and were instrumental in the eventual victory.