A search operation is underway to find three people still missing after a Tunisian passenger plane made an emergency sea-landing yesterday killing 13 people. Authorities have revised the number of passengers onboard. The aircraft,operated by a subsidiary of Tunisair, was carrying 39 and not 38 people – mostly young Italian tourists.The twin-engine plane was on its way from southern Italy to the Tunisian tourist resort of Djerba. The pilot asked to make an emergency landing in Sicily. Survivors of the crash say he lost power and came down in the sea. So far, the French-made plane’s black boxes have not been found. Floats have been placed under the aircraft’s fuselage and it was towed to the Sicilian port of Palermo. The survivors were rushed to a hospital there. Eleven are in a critical condition. A joint Tunisian, Italian and French investigation is underway to find out exactly what caused the plane to crash.