A Thai jumbo jet has been forced to make an unscheduled landing because a co-pilot caught his leg between a seat and the instrument panel, authorities said.

The captain of the Thai Airways Boeing 747 requested the non-emergency landing Thursday night at the Adelaide airport, Civil Aviation Authority spokesman John Morris said today.Flight 484 was flying from Melbourne to Bangkok with about 300 people on board.

Airport officials said it appeared the incident happened when the first and second officers were switching over in a cockpit seat. The plane's operation was unaffected by the problem because the captain was in another seat, they said.

A doctor and an engineer were able to extricate the first officer, and the flight resumed after a two-hour delay.