On July 9, 2003, about 0900 Alaska daylight time, the captain of a Cessna 208B airplane, N410GV, was seriously injured when the airplane encountered turbulence during normal cruise flight, about 50 miles northwest of Kotzebue, Alaska. There was no damage to the airplane, which was being operated by Hageland Aviation Services Inc., Anchorage, Alaska, as a scheduled visual flight rules (VFR) passenger/cargo flight under Title 14, CFR Part 135 when the accident occurred. The first officer and the sole passenger were not injured. Visual meteorological conditions prevailed, and a company VFR flight plan was filed. The flight departed Kotzebue about 0830, and was bound for Point Hope, Alaska. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on July 9, the director of operations for the operator said that about 30 minutes after the airplane departed Kotzebue, the captain went to check the cargo, leaving the first officer to fly the airplane. He said while the pilot was out of his seat, the airplane encountered unforecast turbulence, and the captain fell, breaking his ankle. He said the first officer returned the flight to Kotzebue to seek medical attention for the captain.