Boeing Co said it was recommended to suspend the use of 777 jets of the same type of junk-throwing engine over Denver over the weekend after U.S. regulators announced additional inspections and Japan suspended their use while considering further action.
The move with Pratt & Whitney 4000 engines came after a United Airlines 777 landed safely at Denver International Airport on Saturday local time after the correct engine failed.
United said the next day that they would voluntarily and temporarily remove their 24 active aircraft, hours before Boeing’s announcement.
Boeing said 69 of the aircraft were in operation and 59 were stored, at a time when airlines have grounded aircraft due to strong demand in connection with the COVID-19 pandemic.
The manufacturer advised airlines to suspend operations until US regulators identified the appropriate inspection protocol.
The 777-200 and 777-300s are older and less fuel efficient than newer models and most operators are phasing them out of their fleets.
Photos published by police in Broomfield, Colorado showed significant debris on the ground, including the engine hood scattered outside a home and what appeared to be other parts of a field.
The National Transportation Safety Board (NTSB) said that the first investigation of the plane showed that most of the damage was limited to the correct engine, with only minor damage to the aircraft.
It was stated that the inlet and the housing separated from the motor and that two fan blades were broken, while the rest of the fan blades showed damage.
The Japanese Ministry of Transport ordered Japan Airlines Co Ltd (JAL) and ANA Holdings Inc to suspend the use of 777s with P & W4000 engines while considering further action.
The ministry said that on December 4, 2020, a JAL flight from Naha Airport to Tokyo International Airport returned to the airport due to a fault in the left engine approximately 100 kilometers north of Naha Airport.
That plane was the same age as the 26-year-old United Airlines plane involved in the latest incident.
United is the sole US operator of the aircraft, according to the Federal Aviation Administration (FAA). The other airlines that use them are in Japan and South Korea, the US agency said.
“We reviewed all available safety data,” the FAA said in a statement. “Based on the original information, we concluded that the inspection range would be strengthened for the hollow fan blades that are unique to this engine model, which is only used on Boeing 777 aircraft.”
Japan said ANA operated 19 of the type and JAL operated 13 of them, although airlines said their use had declined during the pandemic. JAL said that its fleet would be retired in March 2022.
Pratt & Whitney, owned by Raytheon Technologies Corp., was not immediately available for comment.
A spokeswoman for the South Korean Ministry of Transportation, who spoke before Boeing recommended stopping operations, said it was monitoring the situation but had not yet taken any action.
Korean Air Lines Co Ltd said they had 12 of the aircraft, half of which were stored, and that they would consult the manufacturer and regulators and stop flying them to Japan at the moment.
In February 2018, a 777 of the same age operated by United and on its way to Honolulu was hit by an engine failure when a hood fell off approximately 30 minutes before the plane landed safely. The NTSB ruled that the incident was the result of a full-length fan failure.
Because of the 2018 incident, Pratt & Whitney reviewed inspection records for all previously inspected PW4000 fan blades, NTSB said. The FAA in March 2019 issued a directive requiring initial and recurring inspections of the fan blades on the PW4000 engines.