On his 30th birthday in 2008, Macartney competed in the Hahnenkammdownhill in Kitzbühel, Austria. The second racer on the course, he had an excellent run going until he suffered a spectacular fall just five seconds from the finish line. After descending the steep Zielschuss section and reaching a speed of 87.75 mph (141.22 km/h), Macartney was challenging for a top ten finish. At the final jump (Zielsprung), he was twisted left while airborne, could not recover, and crashed whilst finishing the race. He was airlifted by helicopter to a hospital in Innsbruck, said to have suffered bruising to the brain, and was put into an induced coma.[2] He regained consciousness the next day.[3] As Macartney did not miss a gate, he finished the race in 33rd place with a time of 1:55.91, 3.16 seconds behind the winner, Didier Cuche.[4] Macartney's speed at the end of the Zielschuss was the highest of the race; the next closest speed was 86.5 mph (139.2 km/h) by Bode Miller, who tied for second.
Macartney recovered from his injuries and was named to the top team ("A Team") of the U.S. Ski Team for the 2008-09World Cup season.[5]