United Airlines shows signs of metal fatigue

The United Airlines plane that caught fire and dropped debris on Broomfield showed signs of metal fatigue inside its engine, federal investigators said Monday after a preliminary, on-scene examination of the right engine’s fan blades.

Investigators want to determine at what point the metal fatigue star ted and whether it caused a fan blade inside the engine to break off at the root, hit another blade and tear the engine apart, forcing the Hawaii-bound United Flight 328 to turn around minutes after takeoff for an emergency landing in Denver.

The incident is similar to another engine failure that happened in the Netherlands on Saturday, both drawing international attention and prompting plans for new safety measures. Meanwhile, Broomfield police said they were overwhelmed by calls about plane debris this weekend, and residents whose property was damaged are hoping United Airlines will pay for repairs.

The engine failure that happened in flight over Denver put a gash in the fuselage of the plane, National Transportation Safety Board Chairman Robert Sumwalt said during a Monday evening news conference. He could not say how close the puncture under the right wing might have come to depressurizing the cabin, but said there was no structural threat to the plane.

“It’s basically fiberglass,” he said. “… it can be fairly easily punctured. You couldn’t go up and sock it with your fist, but a piece of metal flying at a high speed could puncture it. It is not structural in nature.”

Residents in not only Broomfield but also the Netherlands dodged falling engine par ts from Boeing planes Saturday. Two Dutch people were injured when a Boeing 747 cargo plane also experienced an engine failure after takeoff Saturday and dropped debris on a residential area and vehicles in Meerssen, according to the Dutch Safety Board.

The engines on that Boeing 747 are a smaller version of the Pratt & Whitney 4000-112 engine on the Boeing 777-200 that caught fire over Broomfield, according to Reuters.

United Airlines grounded its other Boeing 777 planes with the same engine, and the Federal Aviation Administration ordered increased safety inspections for that model of engine, which has a unique hollow fan blade and is used only on Boeing 777 planes. In Japan, the Civil Aviation Bureau suspended all operations of Boeing 777s with the same engines.