Dozens of Boeing 777s grounded after United Airlines engine failure

Key Points
  • The FAA says it will order inspections of some Boeing 777 jetliners after an engine failure on a United flight.
  • United Flight 328 made an emergency landing back at Denver International Airport shortly after takeoff. Debris was discovered in several neighborhoods, including an engine covering. No injuries were reported on board the plane.
  • Japan's aviation regulator halted flights with this kind of engine until further notice.
Boeing 777 jetliners face FAA investigation after an engine failure on a United flight
Boeing 777s face FAA investigation after an engine failure on a United flight

United Airlines said Sunday that it will temporarily remove 24 of its Boeing 777s from service after one of the planes suffered an engine failure over the weekend.

The head of the Federal Aviation Administration said Sunday the agency will order the inspection of some Boeing 777 jetliners powered by the same Pratt and Whitney engine, the PW4077.

Japan's aviation regulator has ordered airlines to suspend flights of aircraft with this type of engine until further notice, the FAA said. United is the only U.S. airline with this type of engine in its fleet, added the agency.

United Flight 328, a Boeing 777-200 bound for Honolulu, made an emergency landing at Denver International Airport shortly after takeoff on Saturday afternoon after its right engine failed.

No one was injured in the flight that was carrying 229 passengers and 10 crew members, but debris, including what appeared to be a piece of the engine covering, fell in nearby Broomfield, Colorado.

United Airlines flight UA328, carrying 231 passengers and 10 crew on board, returns to Denver International Airport with its starboard engine on fire after it called a Mayday alert, over Denver, Colorado, U.S. February 20, 2021.
Hayden Smith/@speedbird5280 | via Reuters

Separately, Boeing said it recommended the halting of its 777 aircraft with the same kind of engine as the United flight that dropped debris near Denver.

"While the NTSB investigation is ongoing, we recommended suspending operations of the 69 in-service and 59 in-storage 777s powered by Pratt & Whitney 4000 engines until the FAA identifies the appropriate inspection protocol," Boeing said in a statement.

Shares of Raytheon Technologies, parent of engine maker Pratt and Whitney, were down 0.4%, while Boeing was up 0.5% in early afternoon trading.

Federal investigators said their initial investigation revealed two of the right engine's fan blades were fractured.

The National Transportation Safety Board said one of the engine's fan blades was fractured near its root while another was fractured half-way through. Other engine fan blades were also damaged, the NTSB said in an initial report late Sunday.

"We reviewed all available safety data following yesterday's incident. Based on the initial information, we concluded 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," FAA administrator Steve Dickson said in a statement.

United has another 28 of these aircraft in its fleet that are currently in storage. Airlines parked or retired dozens of planes after demand fell because of the Covid-19 pandemic. The planes are also operated in Japan and South Korea.

Engine maker Pratt and Whitney, said in a statement that it sent a team to work with the U.S. investigators. The company said it is "actively coordinating with operators and regulators to support the revised inspection interval of the Pratt & Whitney PW4000 engines that power Boeing 777 aircraft."

Residents take pictures of debris fallen from a United Airlines airplane's engine on the neighborhood of Broomfield, outside Denver, Colorado, on Feb. 20, 2021. A United Airlines flight suffered a fiery engine failure Feb. 20, shortly after taking off from Denver on its way to Hawaii, dropping massive debris on a residential area before a safe emergency landing, officials said.
Chet Strange | AFP | Getty Images

Pratt and Whitney said it will "work to continue to ensure the safe operation of the fleet."

United said it operates 44 other Boeing 777s that are powered by General Electric engines.

Such incidents are rare but have occurred recently and regulators will likely examine common threads.

Dutch regulators said are investigating an engine fire on a Boeing 747 cargo plane that was also powered by Pratt and Whitney PW4000 engines, after parts of one of the engines fell shortly after takeoff from Maastricht.

One of the Pratt and Whitney PW4000 engines on a Tokyo-bound Japan Airlines Boeing 777-200 failed during a Dec. 4 flight, forcing it to return to Naha, Japan. Fan blade damage was later detected. Japan Airlines said it strengthened its maintenance program as a result of the incident.

In February 2018, another United Airlines 777-200 outfitted with Pratt and Whitney PW4077 engines, the same type involved in Saturday's incident outside of Denver, suffered engine failure over the Pacific near Hawaii, after a fan blade fractured, according to an NTSB report released in June. The incident prompted Pratt & Whitney to step up its fan-blade inspection processes. The flight made it safely to Honolulu with 364 passengers and 10 crewmembers.

In April 2018, a passenger was killed when a fan blade broke off from a Southwest Airlines Boeing 737's engine, breaking a window and briefly sucking the passenger partially outside. Federal regulators ordered airlines to step up fan-blade inspections of those engines after that incident.

The PW4000 engines has been in service for 34 years, more than 25 on the 777, said Richard Aboulafia, vice president of analysis at Teal Group. About half of the 3,200 that have been built are in service, he said.

United temporarily grounds 24 Boeing 777s following incident of engine failure
United temporarily grounds 24 Boeing 777s following incident of engine failure