New Zealand's Civil Aviation Authority (CAA) has temporarily banned Pratt & Whitney PW4000-powered Boeing 777 aircraft from operating in its airspace. “We are issuing a NOTAM today which effectively prevents this aircraft type from landing or taking off within New Zealand domestic airspace or transiting through it," CAA’s deputy chief executive aviation safety, Dean Winter says in a statement today. CAA says this follows the recent engine failure of a United Airlines aircraft with the same profile, on 20 January. The incident occurred during flight 328 from Denver to Honolulu. The aircraft made a successful emergency landing and there were no injuries. Data shows that the aircraft, bearing registration N772UA (MSN 26930), is a 1995-built, 777-200 fitted with PW4077 engines. CAA's Winter states: “We are taking this action out of an abundance of caution to prevent any potential threat to people or property should another engine experience a similar fan blade failure like the incident in Denver." He adds: “We have quickly joined the aviation regulators in the United Kingdom and Japan in taking this action. We also note Boeing has recommended the suspension of all 777 with the affected engines until the cause of this failure is known. We anticipate that an emergency airworthiness directive will be issued by the USA’s Federal Aviation Administration to further clarify and take action on this situation.” He further states: “We are quite satisfied that there is enough evidence to take this action in the interest of keeping New Zealand’s skies safe and secure.” CAA says there are no PW4000-powered 777 aircraft operated by New Zealand-based airlines. Data shows that United Airlines is the largest operator of PW4000-powered 777s, and its in-service and stored fleet of 52 777-200s average 22.5 years old. ANA is the next largest operator, with 15 777-200s and seven -300s in its existing fleet. Korean Air operates 16 777s and its low-cost affiliate Jin Air operates another four; Japan Airlines has 13 in its fleet. These operators also have a mix of -200s and -300s.

Dutch investigators have opened an initial probe into an incident in which a Boeing 747-400 freighter apparently shed engine parts after departure from Maastricht. The aircraft had “engine problems” and lost several metal parts after it took off from Maastricht-Aachen airport on 20 February, before diverting to Liege, says the South Limburg arm of safety co-ordination authority Veiligheidsregio. Metal parts fell in the Sint Josephstraat district of Meerssen, which lies between the city and the airport, about 2km along the extended centreline of runway 21. “Two people were slightly injured. One of them was taken to hospital,” the authority adds. ”Several cars and houses were damaged.” While the Dutch Safety Board has not formally identified the aircraft involved, it appears to be a Longtail Aviation 747-400 converted freighter. The aircraft – provisionally identified as VQ-BWT, originally delivered in 1991 to Singapore Airlines – took off from Maastricht for New York at about 16:10. According to fleets data it is fitted with Pratt & Whitney PW4056 engines, from the same powerplant range – although a different model – as the PW4077 engine involved in the United Airlines Boeing 777 uncontained failure event over Denver on the same day. Maastricht airport’s operator says an “engine fire started” after the 747 departed and it “lost debris” over Meerssen before landing in Liege. The Dutch Safety Board says it has commenced an “exploratory investigation” into the event – a month after it started looking into the shedding of an underside fuselage panel of another 747-400 freighter which had been climbing to cruise altitude over the Netherlands. South Limburg’s safety authority says the police have requested any debris found to be left alone, and that damage to vehicles or other property should be reported to insurance companies.

The US National Transportation Safety Board is co-ordinating with Pratt & Whitney to determine if metal fatigue caused two fan blades of a PW4000 engine to break off during United Airlines flight 328 on 20 February, causing the engine to catch fire. Fan blade fragments that broke off during the flight of the United Boeing 777-220 will be inspected for scratches on the blades that would indicate metal fatigue, NTSB chairman Robert Sumwalt said during a press conference on 22 February. The PW4000 engine will also be removed from the 777 and will be inspected by the NTSB in Washington, DC, where its maintenance history will also be reviewed. The 777 flight-data and cockpit-voice recorders will also be analysed in Washington, DC. "Our mission is to understand what happened and why it happened to keep it from happening again," Sumwalt said. The federal investigation has just begun, so Sumwalt shared with reporters what is known so far about the incident during which nobody was injured, even though engine debris both hit the aircraft and landed in a residential area. Two fan blades broke off from an engine during the United flight from Denver to Honolulu: one broke off at the root and the adjacent blade broke at mid-span. Fragments of one blade became lodged in an engine containment ring. Debris struck the aircraft leaving scratches and causing "minor damage" to the fairing that connects the wing to the fuselage but there was "no structural damage" that endangered the integrity of the aircraft, Sumwalt said. The engine failure caused the PW4000 to catch fire, so the flight crew engaged the emergency fire extinguisher and cut the fuel line to the engine, yet video taken by a passenger shows that it continued to burn. The NTSB is so far uncertain why these steps did not extinguish the fire. While the aircraft landed safely back in Denver after the engine failed, one of the large containment rings meant to catch debris during incidents landed in a soccer field in Broomfield, Colorado, Sumwalt said, adding that nobody was injured by the debris. The NTSB is also so far uncertain why the cowling broke off. Based on initial investigation, the NTSB does not consider this to be an uncontained engine failure according to the traditional definition, "since the ring contained the parts as they were flying out," Sumwalt said. The NTSB will look for similarities with past incidents of PW4000 engines. Two other PW4000 failures in recent years involved a Japan Airlines 777 in December 2020 and a United 777 over the Pacific Ocean in 2018. Investigators traced the 2018 incident to a blade failure. The PW4000 on a Korean Air 777 also caught fire in 2016.