Boeing has called for the grounding of all 128 planes of its Boeing 777-200’s that use Pratt & Whitney PW4000 engines as US regulators investigate a United Airlines plane whose engine exploded and rained down debris over Denver.
United and Japan’s two main airlines – Japan Airlines and All Nippon Airways – confirmed they have already suspended operations of 56 planes fitted with the same engine which disintegrated mid-flight over Colorado on Saturday.
United, the only US carrier with the PW400 in its fleet, accounts for 24 of those aircraft, while the Japanese operators have 32.
South Korea is the only other country using the same combination of a Boeing 777-200’s with a Pratt & Whitney PW4000 engines – although operations have not been suspended there, with officials there awaiting instructions from Korean regulators. A further 59 of the total 128 planes are not in service.
An investigation into what caused United Flight 328’s engine to fail in Denver on Saturday is currently being conducted by the National Transportation Safety Board (NTSB).
Officials with NTSB have revealed that two of the planes engine fan blades were ‘fractured’ and the remaining blades all exhibited signs of damage, but said it’s too early to draw conclusions into how the incident happened. NTSB investigations can take up to a year or longer, although in major cases the agency generally releases some investigative material midway through the process.
Boeing has said the aircraft should be taken out of service until the Federal Aviation Authority had determined an inspection procedure.
‘While the NTSB investigation is ongoing, we recommended suspending operations of the 69 in-service and 59 in-storage 777 aircraft powered by Pratt & Whitney 4000-112 engines,’ the company said.
In the United Kingdom, the country’s transport secretary announced Monday morning that all Boeing 777s with PW4000 engines will be banned from flying over British airspace until further notice.
Pratt & Whitney, meanwhile, said it was ‘actively co-ordinating’ with planemakers and federal regulators after the FAA called for emergency inspections, adding that it had dispatched a team to work with investigators looking at what went wrong on Saturday’s flight.
In a separate blow to Pratt & Whitney, which is one of the three major players in the aircraft engine market along with General Electric and Britain’s Rolls-Royce, another of its engines was involved in a similar incident in the Netherlands on Sunday which saw a Boeing 747 freighter drop debris onto a Dutch town, injuring two people.
The share prices of Pratt’s parent company, Raytheon, plunged 2.77 percent as of 7am EST Monday in pre-market trading, a major boost to its competitors.
On Sunday, the Federal Aviation Administration (FAA) said it would require stepped-up inspections of 777 aircraft with Pratt & Whitney PW4000 series engines after the right engine failure on United Flight 328.
In a statement released yesterday evening, FAA Administrator Steve Dickson said: ‘After consulting with my team of aviation safety experts about yesterday’s engine failure aboard a Boeing 777 airplane in Denver, I have directed them to issue an Emergency Airworthiness Directive that would require immediate or stepped-up inspections of Boeing 777 airplanes equipped with certain Pratt & Whitney PW4000 engines.
‘This will likely mean that some airplanes will be removed from service,’ he added.
Dickson said that his team has ‘reviewed all available safety data following yesterday’s incident,’ and ‘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’.
According to Dickson, the FAA ‘is working closely with other civil aviation authorities to make this information available to affected operators in their jurisdictions’.
He said his team will be meeting with Pratt & Whitney and Boeing ‘to finalize the details of the Airworthiness Directive and any accompanying service bulletins to ensure that the appropriate airplanes are included in the order’.
Meanwhile, Japan has requested airlines avoid using Boeing 777 planes with Pratt & Whitney 4000 engines for take-offs, landings and overflights in its territory until further notice, the Japan Aeronautical Service Information Center said.
Japan said on Sunday that 32 passenger jets that use the same family of engine as the Boeing 777 involved in the Denver incident have been grounded.
The planes affected by the order from the Ministry of Land, Infrastructure, Transport and Tourism, are 13 aircraft operated by Japan Airlines.
The other 19 planes are operated by All Nippon Airways. None of the planes are scheduled to fly on Monday.
Japan Airlines had a similar incident occur in December 2020 after the crew requested to make an emergency landing nine minutes after taking off. The plane returned safely to Naha with none of the 178 passengers and 11 crew injured.
Officials said at the time that the left engine experienced a malfunction at approximately 16,000-17,000 feet.
In the UK, Transport Secretary Grant Shapps said all PW4000-equipped Boeing 777s would be banned from flying in British air space.
In a tweet, Shapps wrote: ‘After issues this weekend, Boeing B777s with Pratt & Whitney 4000-112 series engines will be temporarily banned from entering the UK airspace. I will continue to work closely with the UK CAA to monitor the situation’.
All of the announcements occurred within 48 hours of the United Airlines plane suffering catastrophic engine failure shortly after take-off.
The Boeing 777-200 aircraft, carrying 231 passengers and 10 crew on board, was heading to Honolulu on Saturday from Denver International Airport when debris struck the plane’s right engine, causing it to erupt into flames.
The captain had been giving an announcement over the intercom when a large explosion rocked the cabin, accompanied by a bright flash.
Passengers recalled their horror as they looked out the window to see engine casing and chunks of fiberglass falling from the plane, and thick black smoke emanating from the wing.
The incident forced the pilot to attempt an emergency landing back in Denver just 20 minutes after take-off, at around 1.30pm local time.
Video recorded aboard Flight UA328 captured the moment it touched back down on the runway safely, prompting the cabin to erupt in applause and cheers of relief.
Remarkably, there were no injuries reported either on board the flight or on the ground.
The National Transportation Safety Board said that two of the engine’s fan blades were fractured and the remainder of the fan blades ‘exhibited damage.’ The NTSB declined to draw conclusions about how the incident happened, insisting it’s too early to tell.
Aviation Safety expert John Cox, however, said the 26-year-old plane appeared to have suffered uncontained and catastrophic engine failure.
Such an event is extremely rare and happens when huge spinning discs inside the engine suffer some sort of failure and breach the armored casing around the engine that is designed to contain the damage.
Pilots practice how to deal with such an event frequently and would have immediately shut off anything flammable in the engine, including fuel and hydraulic fluid, using a single switch.
Speaking to the Today show on Monday morning, Greg Feith, a former NTSB air safety investigator, expressed his concern over not only how the engine came to be damaged in the first place, but that it caught fire and continued to burn until landing.
When asked what would’ve happened to those on board if the engine failure happened over the Pacific, Feith said: ‘Well there’s two parts to that answer, and that is one: the FAA requires that a manufacturer of a two engine aircraft like this certify it so that it can fly with one engine – which it did successfully.
‘However, had this aircraft been over the ocean for an hour, or two hours, the bigger concern, besides the parts coming off, is the fact is there is this post-event fire. And I’m not sure why that fire continued to burn, because there is a fire suppression system in that engine.’
Another cause for concern, Feith said, was how the frame of the engine continued to fall apart, sending debris raining down on the ground below.
‘These [engine] blades – blades – this is the fan section so these are the largest blades of the engine – and if they come out of the engine like they did, of course it took the engine’s casing.
‘With the plane travelling at 200 to 300 miles per hour, the aerodynamic forces helped take the rest of this engine covering off – that is a big concern because the engine does have something called a containment frame so that shrapnel does not damage the rest of the engine.’
United is the only US airline with the Pratt & Whitney PW4000 in its fleet, the FAA said. United says it currently has 24 of the 777s in service.
United says it will work closely with the FAA and the NTSB ‘to determine any additional steps that are needed to ensure these aircraft meet our rigorous safety standards and can return to service.’
The NTSB said the cockpit voice recorder and flight data recorder were transported to its lab in Washington for the data to be downloaded and analyzed. NTSB investigations can take up to a year or longer, although in major cases the agency generally releases some investigative material midway through the process.
Former National Transportation Safety Board Chairman Jim Hall called the incident another example of ‘cracks in our culture in aviation safety [that] need to be addressed’.
Hall, who was on the board from 1994 to 2001, has criticized the FAA over the past decade as ‘drifting toward letting the manufacturers provide the aviation oversight that the public was paying for’.
Prior to Flight UA328 landing safely on Saturday, large chunks of debris had fallen from the plane on the Denver suburbs below, narrowly missing homes and other buildings.
Passenger David Delucia recalled for the Denver Post how he grabbed his wife’s hand after hearing the explosion, telling her: ‘We’re done for.’
‘The plane started shaking violently, and we lost altitude and we started going down,’ Delucia, who sat directly across the aisle from the side with the failed engine, said.
‘When it initially happened, I thought we were done. I thought we were going down. I thought we were going to die at one point,’ he said, adding that he and his wife took their wallets containing their driver’s licences and put them in their pockets so that ‘in case we did go down, we could be ID’d’.
In an audio recording, a United pilot could be heard making a mayday call to air traffic control.
‘Mayday, aircraft just experienced engine failure, need to turn immediately,’ the pilot said, according to audio from the monitoring website liveatc.net that was reviewed by Reuters.
Denver resident Kirby Klements was inside his home with his wife when they heard a huge booming sound.
A few seconds later, the couple saw a massive piece of debris fly past their window and into the bed of Klements’ truck, crushing the cab and pushing the vehicle into the dirt.