In 1978, Macartney-Snape travelled to India as part of the ANUMC's expedition to Dunagiri (7,066 m). After prolonged bad weather he and Lincoln Hall radioed to the Expedition Leader, Peter Cocker, that they wanted to make another attempt on East Dunagiri. Cocker, who was alone at the time at Col Camp on Dunagiri, invited them instead to make a final attempt on Dunagiri. If they could force through a route to the Summit Ridge, they could then return to Col Camp and wait for support to make the summit attempt. Maccartney-Snape and Hall agreed, returned to Dunagiri, and then pushed through to the Summit Ridge. The weather cleared, and after they spent a clear but very cold night out without sleeping bags, Macartney-Snape and Hall made an audacious attempt for the summit of Dunagiri. They were successful and the pair then descended through an electrical storm. Maccartney-Snape reached Col Camp at 10.30 p.m.; however, Hall spent another night out on the mountain. During the night, Cocker ascended the fixed ropes to meet him and accompany him back to Col Camp. This was the first major Himalayan summit climbed by an Australian.