Showers of jet engine parts over residential areas on both sides of the Atlantic have resulted in the suspension of some older Boeing planes from service.
Saturday’s incidents involving a United Airlines 777 in Denver and a Longtail Aviation 747 freighter in the Netherlands put engine maker Pratt & Whitney in the spotlight, though there is no evidence the incidents are related.
A woman sustained minor injuries in the Dutch incident, which scattered turbine blades on the town of Meerssen. One was found embedded in a car roof.
US jet engine-maker Pratt & Whitney said it was coordinating with regulators to review inspection protocols.
After the US engine failure, when a United flight dropped debris on a north Denver suburb before landing safely, Boeing recommended the suspension of 777s with the same turbine. Japan, meanwhile, imposed a mandatory suspension.
Following the US and Japan, South Korea and the UK announced they would also temporarily ban all Boeing 777 powered by the Pratt & Whitney engine from operating in their airspace, Aerotime reported.
The EU Aviation Safety Agency on Monday, requested more information on the Pr&W engines involved. They then said the incidents were unrelated. “Nothing in the failure and root analysis show any similarity at this stage,” the regulator said.
The US Federal Aviation Administration (FAA) said it would soon issue an emergency airworthiness directive based on the United event.
Both incidents involve the same type of PW4000 engine that equips a relatively small number of older planes, some grounded by the Covid-19 pandemic, limiting the likely repercussions.
The incidents nonetheless bring a new headache for Boeing as it recovers from the much more serious 737-MAX crisis, which resulted in the grounding of its flagship narrowbody jet after two deadly crashes.
“This is certainly an unwelcome situation for both Boeing and Pratt, but from time to time issues will pop up with aircraft and engines,” said Greg Waldron, a managing editor at industry publication Flight Global.
“The PW4000-powered 777-200 is slowly leaving service,” he said, adding that the pandemic slump means that airlines forced to suspend it “should be able to fill any network gaps” with 787s or other 777s equipped with General Electric Co engines.
In the Dutch case, the Longtail pilot was informed of an engine fire by air traffic control after taking off from Maastricht, bound for New York, and diverted to Liege, Belgium.
Examination of the 26-year-old United jet showed damage was mostly confined to the right engine, the National Transportation Safety Board (NTSB) said. Its inlet and casing came off and two fan blades were fractured, with others showing damage.
The FAA said early findings suggested that the “inspection interval should be stepped up for the hollow fan blades that are unique to this model of engine, used solely on Boeing 777 airplanes”.
The smaller PW4000 engines on some Boeing 747s and 767s, as well as some Airbus A330s, do not feature the hollow titanium fan blade suspected of being involved in the United 777 incident.