On the night of 5 June, HMS Cardiff was stationed to the east of the islands to provide gunfire support to the land forces and intercept enemy aircraft. At around 02:00 a radar contact was detected; a British Army Air Corps Gazelle helicopter was making a routine delivery of personnel and equipment to a radio rebroadcast station on East Falkland. From the contact's speed and course, Cardiff's operations room crew assumed it to be hostile.