The French first officer of an AirAsia passenger jet that crashed into the sea last month was at the controls just prior to the accident, Indonesia's lead investigator said on Thursday.

The tail of a crashed AirAsia jet has been found upturned on the sea bed about 30 km (20 miles) from the plane's last known location, Indonesia's search and rescue agency said on Wednesday, indicating the crucial black box recorders may be nearby.

Ships and aircraft criss-crossed the seas off Borneo on Friday hunting for the wreck of an Indonesia AirAsia passenger jet, but bad weather was again hindering the search for the plane and the black box flight recorders that should reveal why it crashed.

The search for a missing airliner with 162 people aboard will expand Tuesday, the Indonesian government announced.

Any foreign investor entering the Indian civil aviation market will know the unwritten rule before making any public announcement of his intent: Always seek the blessings of the ministry beforehand.