American Airlines, already grappling with union issues and bankruptcy fallout, is now confronting a third problem: growing reports of loose seats.

On Tuesday, the company said another flight had experienced loose seats, bringing the total to three flights on two planes in a week.

A plane headed from Vail, Colorado, to Dallas on September 26 had seats come loose, the airline's vice president of safety confirmed Tuesday.

The same aircraft experienced a similar problem on a New York to Miami flight on Monday morning. That flight had to return to John F. Kennedy Airport.

Separately, a Boeing 757 from Boston to Miami carrying 175 passengers diverted to New York on Saturday when three seats in row 12 came loose shortly after takeoff.

The airline said it would inspect 47 Boeing 757 planes after the incidents.

"Originally, American planned to evaluate the seats on eight Boeing 757 airplanes, but out of an abundance of caution, the decision was made to proactively evaluate a total of 47 Boeing 757 airplanes that have the same model Main Cabin seats with a common locking mechanism," company spokeswoman Andrea Huguely said in a statement.

"American's internal investigation has focused on one of three types of Main Cabin seats on the 757s and how the rows of these three seats fit into the track that is used to secure the rows to the floor of the airplanes. Our maintenance and engineering teams have discovered that the root cause is a saddle clamp improperly installed on the foot of the row leg," she said.

The clamps were used on 47 of the company's 102 Boeing 757 airplanes.

So far, American Airlines has inspected at least 36 planes and found that six -- including the two involved in the recent diversions -- had seats that were not properly secured. Not all of the seats were loose, the company said, but they had the potential to become loose.

Eleven aircraft could be inspected Wednesday.

Huguely said the seats issue does not appear to be connected to any one work group or maintenance facility, and apologized for any inconvenience to customers.

"Safety is -- and always will be -- American's top concern," the spokeswoman said.

The Federal Aviation Administration is looking into the incidents of loose seats, which are the latest in a string of woes for American Airlines.

Earlier Tuesday, an American Airlines flight from Chicago to London made an unscheduled landing at Shannon Airport in Ireland after a passenger reported a smoky odor, an airline spokesman said.

American Airlines Flight 98, a Boeing 777-200 carrying 246 passengers and 14 crew members, was diverted as a precaution, airline spokesman Ian Bradley said.

An inspection revealed that the odor was coming from an overhead fan that had overheated, he said.

Niall Maloney, head of operations for Shannon Airport, said such technical diversions are not uncommon.

The airline has also been beset recently by labor troubles, delays and flight cancellations.

American, which filed for Chapter 11 bankruptcy protection late last year, persuaded a judge to throw out its contract with the pilots union last month.