NEW DELHI, July 14 (Reuters) - A preliminary investigation into the crash of an Air India passenger jet last month that killed 260 people raises additional questions about the incident and the investigation is far from over, Air India's CEO said in a memo on Monday.

The preliminary report into the probe of an Air India plane crash in Ahmedabad last month raises several questions but does not provide any answers, the International Federation of Air Line Pilots' Associations (IFALPA) has said.

Air India CEO confirms all Boeing 787 aircraft checked post-crash, no mechanical issues found, urges against premature conclusions.