The flight departed uneventfully from New-York for Amsterdam Approximately two and half hours after take-off, the pain in the back of F/0 became unbearable again so much so that F/0 excused himself from the cockpit and decided to lie down in the bunk provided adjacent to the cockpit. After sometime the F/0 opened the cockpit door and called the Flight Engineer (F.E) for help. The F.E requested the Captain to announce for a doctor. The doctor was made available as he was sitting in upper deck, who administered him pain killing injection but the pain did not subside. Another announcement was made & two more doctors offered their services but by that time the F/0 had expired and was declared dead on board the aircraft.