A nearly 200-pound piece of metal broke off an engine of a Northwest Airlines jet Saturday afternoon and landed in an Inver Grove Heights, Minn., field, about 100 yards from a home.
The part that fell off is a "thrust reverser nozzle," used to slow the plane on landing. It fell off a DC-10 flying from Minneapolis-St. Paul to Honolulu, landing near the intersection of South Robert Trail and 70th Street.
No one on the ground was injured, police said, and federal authorities say the plane landed without incident in Hawaii. An anonymous caller reported the incident about 3:45 p.m. Saturday, said Sgt. Greg Olson of the Inver Grove Heights Police Department.
A serial number on the part shows it belongs to Northwest. Pilots did not notice the part missing until they reached Hawaii, said Elizabeth Isham Cory, a Federal Aviation Administration spokeswoman.
She said the agency has launched an investigation. "It is a very unusual event," Cory said. "In all these situations, we look into what happened and why."
The part had been deactivated, the FAA said, and the plane had another thrust reverser in use. Hal Myers, a spokesman with the Air Line Pilots Association at Northwest, said it's not unusual to fly aircraft with deactivated equipment in place as long as there's no safety issue.
The plane involved has no history of accidents, Cory said. It was manufactured by McDonnell-Douglas in 1974, according to FAA records.
Since 1997, some 20 service difficulty reports about the plane -- registration number N233NW -- have been filed with the FAA. A dozen involved corrosion that was found in various parts of the plane and repaired during the course of regular maintenance checks.
The FAA investigation likely will take several weeks to complete. What could happen to Northwest? "It's too early to say," said Cory. If found to be at fault, the airline could be fined.
Eagan, Minn.-based Northwest didn't have much to say about the incident. "All I can tell you is that we are cooperating with the FAA investigation," said spokeswoman Mary Stanik.
In recent years, the plane involved has been maintained in Singapore, the union for Northwest's mechanics said.
"We have not overhauled our DC-10s in years," said local union President Ted Ludwig. "We don't do anything to them anymore. ... I can't say outsourcing caused this. But I can say that we don't maintain these aircraft."
Mechanics have criticized Northwest for using outside firms to perform certain maintenance on its planes while laying off its in-house mechanics. Outside maintenance work often is poorly done, leaders of the mechanics union have alleged. Northwest and the FAA dismiss the allegations, arguing outsourced maintenance work is up to snuff. Northwest on Monday said in a statement that "outsourced maintenance and in-house maintenance have the same quality standards."
In the past few years, Northwest has cut 3,700 mechanics and related workers while sending an increasing amount of maintenance work to outside companies.