On 2 January 2005, a Boeing 767-300 being operated by Air Canada on a scheduled passenger flight in day VMC from Toronto to Santiago, Chile was approximately 180 nm north of the intended destination and in the cruise at FL370 when it suffered a run down of the left engine which flight deck indications suggested was due to fuel starvation. A MAYDAY was declared to ATC and during the subsequent drift down descent, with the cross feed valve open, the failed engine was successfully restarted and the flight was completed with both engines operating without further incident.