The flight departed with approximately 20 gallons of fuel in each fuel tank and offloaded skydivers at 10,500 feet, then descended to return with the throttle at idle, the fuel/air ratio leaned; and carburetor heat applied. At 2,000 feet, the pilot began to level off and, “realized I was having engine trouble and began my emergency procedures for an engine failure at altitude….”

Read the NTSB report…