Federal investigators are focusing on fan blades as they probe the third Pratt & Whitney mid-air engine failure in as many years, this one raining down debris on houses and fields in a Denver suburb.
Boeing recommended suspending operations of the 69 in-service and 59 in-storage 777s powered by Pratt & Whitney 4000-112 engines until the Federal Aviation Administration identifies inspection protocols.
Even as investigators of the National Transportation Safety Board got to work, engine failure on another Boeing plane equipped with Pratt & Whitney engines caused debris to fall after take-off from Maastricht, The Netherlands. At least one person was injured and a car roof was punctured. The Dutch Safety Board is investigating.
The NTSB said an initial examination of the engine that caught fire Saturday over Broomfield, Colorado, showed parts separated from the engine, two fan blades were fractured and other fan blades were damaged on the tips and leading edges.
Richard Aboulafia, vice president of analysis at the Teal Group, said Monday the PW4000 engine has been in service for 34 years and more than 25 years on the Boeing 777 that was forced to return to Denver International Airport.
Although the investigation has just begun, the problem is “almost certainly a maintenance issue, not a design issue,” he said
“They all have issues. They just go through these things,” Aboulafia said.
Raytheon Technologies Corp., the Waltham, Massachusetts, parent company of Pratt & Whitney, is unlikely to falter over the long-run following the engine failure, he said.
“It will not affect the company’s competitiveness going forward,” he said.
Cowen analyst Cai von Rumohr said in a client note Monday the engine failure is “probably not a major negative” for Raytheon. Boeing 777s powered by PW4000 engines represent just 8% of the total 777 fleet, he said.
After showering the Denver suburb of Broomfield with debris, the United Airlines flight returned to the Denver airport with no reported injuries. The plane was equipped with two Pratt & Whitney PW4000 engines.
No one on the ground was hurt, authorities said.
In February 2018, a United Airlines 777-200 outfitted with Pratt and Whitney PW4077 engines, the same type involved in Saturday’s incident, suffered engine failure over the Pacific near Hawaii, after a fan blade fractured, according to an NTSB report released in June.
The flight made it safely to Honolulu with 364 passengers and 10 crewmembers.
Pratt & Whitney said it stepped up its fan-blade inspection procedures. The NTSB blamed a lack of training. A Pratt & Whitney inspector made an incorrect evaluation and an engine fan blade with a crack was returned to service, the agency said.
In another incident in December, an engine failed on a Japan Airlines flight on a 777-200 headed to Tokyo. Authorities in Japan and the Federal Aviation Administration issued directives requiring more regular inspections of planes and fan blades involving the PW4000 engine.
The affected 777-200s and 777-300s are older and less fuel efficient than newer models and most operators are phasing out their use.
Aboulafia said despite the incidents, “not a single death is attributable” to the aircraft over billions of revenue passenger miles, an industry measurement of the number of paying passengers multiplied by the distance traveled.
Shares of Raytheon Technologies closed at $73, down 1.7%. Boeing fell 2.1%, ending the day at $212.88.