On 26 November 2008, a Boeing 777-200 powered by RR RB211 Trent 800 series engines and being operated by Delta AL on a scheduled passenger flight from Shanghai Pudong to Atlanta was in the cruise at FL390 in day VMC in the vicinity of Bozeman MT when there was an uncommanded thrust reduction or ‘rollback’ of the right engine. Prescribed drills were followed and a descent to FL310 was made after which normal thrust control was regained and the flight continued to the planned destination. None of the 263 occupants were injured.