US aviation chiefs step up inspections after engine failure
:: Second instance of Boeing 777 shedding debris mid-air surfaces
THREE years before Saturday’s harrowing engine failure and aborted Denver-Hawaii flight, another Boeing 777 faced a similar emergency with the same model engine. Both had fractured fan blades and left a trail of debris below, including flying hunks of engine coverings.
Passengers on that February 2018 flight heard a loud bang before their United Airlines jet began to shake violently and pilots struggled to fly with one working engine. Investigators uncovered problems with the inspection process set up by the engine’s manufacturer, Pratt & Whitney, and the Federal Aviation Administration (FAA) in 2019 ordered airlines to regularly scour fan blades for tiny but potentially catastrophic cracks.
The timing for required inspections was based on how many times engines have been used. The FAA said “these thresholds provide an acceptable level of safety”, according to the 2019 order.
After independent investigators from the National Transportation Safety Board (NTSB) said two more fan blades broke on Saturday – large metal chunks from the plane were spread over a mile of the Denver suburb of Broomfield – the FAA said it was reconsidering.
“We concluded the inspection interval should be stepped up,” FAA Administrator Steve Dickson said, noting that a forthcoming emergency order would provide more details.
Aviation experts said investigators will try to determine, among other things, how the failures that preceded the 2018 incident line up with those that led to Saturday’s incident, and whether actions by the FAA, Pratt & Whitney and Boeing to address them were sufficient.
“They’re definitely going to look into this, but they’re not going to initially assume that’s what it is,” said Jeff Guzzetti, who was director of the FAA’s Accident Investigation Division until 2019. “They’re going to have an open mind about other potential failure modes.”
The FAA said on Monday that it already had been “evaluating whether to adjust blade inspections” because of a December 4, 2020, fan blade incident on a Japan Airlines jet. That also was a Boeing 777 with a Pratt & Whitney engine, and led the pilot to return to Okinawa.
A report last month on the Japan incident found that fan blades on the engine were damaged. The nation’s ministry of transport ordered domestic airlines to accelerate inspections on jets with similarly built engines by the end of March. These types of inspections are generally done every seven years in Japan.
Japanese regulators announced on Sunday that they were grounding the jets. United pulled 24 planes from its fleet that same day, and Boeing recommended that air carriers ground 128 of the company’s 777 jets with the same type of engine.
The Denver incident marks the latest safety challenge for Boeing, which recently saw its 737 Max jets return to the skies after two fatal crashes. Boeing said it is “actively monitoring recent events related to United Airlines Flight 328”.
Pratt & Whitney said it sent a team to assist the NTSB, which is investigating Saturday’s incident, and co-ordinating with airlines and regulators on developing new inspection protocols for the engines. (© The Washington Post)