Flight makes emergency landing

• A problem with an air duct caused some cabin panels to come loose


• All 184 passengers and six crew members are safe


• The flight was forced to make a U-turn back to San Francisco

(CNN) -- An American Airlines flight made an emergency landing Monday at San Francisco International Airport after a problem with an air duct caused some cabin panels to buckle, a spokesman said.

All 184 passengers and six crew members are safe, according to American Airlines spokesman Matt Miller.

"The air duct became inoperable and a few of the panels inside the plane came loose. There were no other issues. It was considered an emergency landing because it was an unscheduled landing," Miller said.

American Airlines Flight 2293 was en route from San Francisco to Dallas/Fort Worth International Airport when it was forced to make a U-turn.

The plane, a Boeing 757, will remain out of service until workers can determine what needs to be done to fix it, Miller said.