The Hercules was involved in a combined exercise called 'Cold Stream' between British and Italian Army under call sign 'Chalk 4', and was carrying 46 Italian paratroopers and six British crew members to the Villacidro dropzone located in Sardinia. Shortly after takeoff from Pisa-San Giusto Airport, while climbing at night, the airplane went out of control and crashed into the sea about 7 km offshore. The aircraft was destroyed and none of 52 occupants survived.
Probable cause (official findings): The assumption that the loss of control was the consequence of an in-flight structural failure was not ruled out.