Boeing has suggested that airlines ground all 777s with the sort of engine that blew apart this past weekend after taking off from Denver, and most carriers operating those aircraft said they would take them out of service temporarily.
After one of its flights made an emergency landing at Denver International Airport on Saturday as parts of the engine casing rained on suburban communities, the U.S. Federal Aviation Administration ordered United Airlines to step up inspections of the aircraft. The authorities said none of the 231 passengers or 10 crew were injured, and the flight landed safely. One of the carriers that grounded the planes is Unified.
The emphasis on the stepped-up inspections was described by FAA Administrator Steve Dickson as hollow fan blades unique to the Pratt & Whitney PW4000 engine model and used solely on Boeing 777s. The statement by Dickson said the conclusion was based on an initial safety data analysis and would possibly mean the grounding of certain aircraft.
During a virtual news conference on Monday night, Robert Sumwalt, chairman of the National Transportation Safety Board, said that a shattered fan blade found in the engine had obvious signs of “damage consistent with metal fatigue.” According to a preliminary report, the broken blade struck and fractured the blade next to it as the engine broke apart.
Sumwalt said the blade that first fractured was being flown on a private jet to the headquarters of Pratt & Whitney on Monday night to be examined under the supervision of investigators from the NTSB.
He said, “Our mission is not only to understand what happened, but why it happened, so we can keep it from happening again.”
Boeing said there were 69 777s in operation with the 4000-112 Pratt & Whitney engines and another 59 in storage and reiterated that they should be grounded before an inspection regime is established by the FAA.
United has 24 of the planes in service; according to the FAA, it is the only U.S. airline with an engine in its fleet.
There are another 32 on two Japanese airlines. According to the financial newspaper Nikkei, Japan ordered the planes out of operations, adding that an engine in the same family had trouble in December.
Asiana Airlines has grounded nine aircraft in South Korea, seven of which are in service, and Korean Air has said it has grounded 16 aircraft, six of which are in service.
“We work with these regulators as they take action while these aircraft are on the ground and Pratt & Whitney carries out further inspections,” Boeing said in a statement, referring to American and Japanese regulators.
It was sending a team to cooperate with investigators, the engine manufacturer said.
The emergency landing this past weekend is the latest challenge for Boeing, which has seen its 737 Max aircraft grounded for more than a year after two deadly crashes in 2019 and is struggling due to the coronavirus pandemic in the midst of the enormous reduction in air travel. Late last year, the Max planes started returning to the sky, a major boost for the aircraft manufacturer, which lost billions during grounding because it was unable to supply fresh aircraft to customers.
The Saturday emergency video posted on Twitter showed the engine completely engulfed in flames as the plane soared. Freeze frames taken by a passenger seated slightly in front of the engine from various videos and also shared on Twitter seemed to show a damaged fan blade in the engine.
The passengers on their way to Honolulu said they were terrified that the aircraft would crash after an explosion and a burst of light, whilst the people on the ground saw large pieces of the aircraft pouring down, missing only one house and crushing a truck. Visible from the ground, the explosion left a trail of black smoke in the sky.
United says it will work closely with the FAA and the NTSB “to determine any additional steps necessary to ensure that these aircraft comply with our strict safety standards and can return to service.”
The NTSB said the voice recorder and flight data recorder in the cockpit were transported to its Washington laboratory to examine the data. NTSB inquiries may take up to a year or longer, although some investigative information is usually published by the agency in major cases halfway through the process.
The Ministry of Property, Roads, Transport and Tourism of Japan said that an engine in the PW4000 family suffered trouble on a Japan Airlines 777 flying from Naha to Tokyo on Dec. 4. The airline said that after takeoff, the aircraft had engine trouble and returned to Naha. According to the airline, an investigation demonstrated damage to the engine case and missing fan blades. In reaction, tougher inspections were ordered.
As reported by Nikkei, Japan Airlines and All Nippon Airways will stop operating a combined 32 aircraft with that engine. To correct the name of one of the Japanese airlines listed, this storey has been modified.
These airlines are Japan Airlines, not Japan Airways.