In February 2018, an engine fan blade fractured during a United flight over the Pacific, resulting in engine failure and the loss of the cowl. Like last weekend’s flight, this aircraft was a Boeing 777 with a PW4077 engine. The pilots were able to land the plane safely in Hawaii without injuring the 374 passengers and crew on board.
After investigating this episode, the NTSB blamed Pratt & Whitney, saying one of its inspectors lacked the training to spot signs of a faulty blade, which resulted in the re-commissioning of a blade with a crack where it eventually fractured. In 2019, the FAA ordered further inspections of the fan blades of these engines. More recently, the agency had inspected the fan blade fragment from the Japanese flight and was considering adjusting the component’s inspections, he said Monday.
When airlines buy new planes, they can usually choose which engine to use. In some cases, they can even lease engines from a bank, according to Eric Jones, the chairman of the aviation maintenance science department at Embry-Riddle Aeronautical University.
“They are very interchangeable,” Mr. Jones said.
United became the first customer of the Boeing 777 in the 1990s and chose to equip the aircraft with the new PW4000 engine from Pratt & Whitney. All Nippon Airways, another first customer, also chose this engine.
Once a major airline takes possession of an aircraft, it usually takes responsibility for the routine maintenance and inspections of all parts of the aircraft. Pilots circle the planes before each flight, performing visual inspections, including fan blades. Technicians check various systems. When a part like an engine requires repair or more inspection, it is often sent to a third party or to the manufacturer itself for examination.
“Boeing does not routinely undertake engine maintenance,” the company said in a statement Monday. “All decisions beyond published approved manuals are the responsibility of the operator and the engine manufacturer.”
It is not yet known what caused the engine fire over the Netherlands, but Dutch authorities opened an investigation into the episode on Saturday.