Published: Oct 29, 2010 3:57 PM EDT
Updated: Oct 29, 2010 12:57 PM EDT

MIAMI (AP) - Authorities say a hole was found in the fuselage of a commercial airliner that suddenly lost cabin pressure shortly after taking off from Miami International Airport.

Federal Aviation Administration spokeswoman Kathleen Bergen says oxygen masks were deployed when American Airlines Flight 1640 lost cabin pressure about 30 minutes into its flight late Tuesday. The Boeing 757 had left Miami for Boston.

The plane returned safely to Miami.

Bergen says an inspection of the plane revealed a

1-foot-by-2-foot hole in the upper part of the fuselage just behind a cabin door toward the front of the plane.

The National Transportation Safety Board is investigating.

Messages left early Friday for an American Airlines spokeswoman and an NTSB spokesman were not immediately returned.