New York | “Metal fatigue” is now the preferred avenue for the American authorities to explain the spectacular incident that occurred last week on a United Airlines flight in the United States, which led to the immobilization of part of the world fleet of Boeing 777.
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The US aviation regulator, the FAA, was already planning to impose more stringent inspections of the Pratt & Withney engines equipping the plane before the engine failure which abruptly ended a flight of the American company United Airlines on Saturday. between Denver (Colorado) and Honolulu (Hawaii), following a similar damage in December 2020 on a Japan Airlines aircraft.
After the analysis of elements related to this event in Japan, the FAA “was in the process of evaluating the need to adjust the inspections” of the fan blades of the engines, according to a message sent to AFP.
The regulator also reviewed approximately 9,000 blade inspection reports after another incident involving the same type of aircraft on February 13, 2018 on a United Airlines flight between San Francisco and Honolulu.
The information comes after initial findings from the US office in charge of transportation safety, NTSB, on last week’s incident over Colorado (west).
“A preliminary on-site examination indicates damage consistent with metal fatigue,” NTSB chairman Robert Sumwalt said Monday evening.
The right engine caught fire shortly after takeoff and lost its fairing. As the plane headed back to the airport, a shower of debris, some large, had fallen on a residential area in suburban Denver.
No one was injured on the ground and the aircraft was able to land safely.
Preliminary examination
We speak of fatigue of a material when it has been modified over time, which can lead to cracks and possibly rupture of the structure.
Mr. Sumwalt confirmed that two of the blower blades were damaged. One of them was found on a soccer field, the other remained lodged in the engine.
The FAA, which had ordered additional inspections on the Boeing 777s powered by Pratt & Whitney as early as Sunday evening, will issue a new airworthiness directive for these devices once its safety experts have finished examining the data available on the flight.
The American regulator, whose inaction had been criticized in the crisis of the 737 MAX, another Boeing plane grounded in March 2019 after two close accidents that killed 346 people, is somewhat in the hot seat. The American press, for example, asks why he did not act as he envisioned after the Japan Airlines incident in December.
Saturday’s incident led to the grounding of all Pratt & Whitney-powered Boeing 777s around the world, the 69 currently in service and the 59 in reserve.
Pratt & Withney said he is cooperating with the NTSB and “will continue to work to ensure the safe operation of the fleet”.
Maintenance problem?
The United Kingdom decided on Monday to ban its airspace to the Boeing 777s concerned. And Japan’s Transport Ministry said it had ordered more stringent inspections of the Pratt & Whitney engine after the incident at Japan Airlines, whose flight was to connect Tokyo to Naha, on the island of Okinawa.
The Dutch authorities also announced Monday the opening of two investigations after the fall two days earlier of debris from a Boeing 747-400 cargo plane, which injured two people in the south of the Netherlands.
The incident is a blow to Boeing, which is just recovering from the setbacks of the 737 MAX, which was recently cleared to fly again after a nearly two-year ban.
Boeing is also, like its rival Airbus, affected by the COVID-19 pandemic and its catastrophic consequences on international air transport. This health crisis led to the cancellation of orders for hundreds of devices.
The current problem “has nothing to compare” with the Boeing 737 MAX crisis, however, said Richard Aboulafia, an aeronautics specialist for Teal Group. “After all these years of service, it’s unlikely that this was an engine design issue,” he said, leaning more towards a possible maintenance issue.