NHK has learned that the US military has recovered the black box of the Osprey transport aircraft that crashed off southwestern Japan last month.

The US military's tilt-rotor aircraft was carrying eight crewmembers when it crashed in waters off Kagoshima Prefecture's Yakushima Island on November 29. The bodies of seven crewmembers have been recovered. One remains unaccounted for.

The military raised the main part of the aircraft by Wednesday.

Sources say the black box, which contains flight data, has also been recovered.

The military is expected to analyze the data to determine the cause of the crash.

The Japan Coast Guard has asked the US military for cooperation in an investigation to identify the cause. But based on the Japan-US Status of Forces Agreement and other deals, it needs US consent to examine the aircraft.