US and European airline regulators have ordered emergency inspections of nearly 700 aircraft engines similar to the one involved in a fatal Southwest Airlines engine blow out earlier this week, citing risks of a similar mishap.
The inspections are to be carried out within 20 days.
The directives by the US Federal Aviation Administration (FAA) and the European Aviation Safety Agency for inspections of CFM56-7B engines, made by CFM International, indicated rising concerns since a similar failure in 2016 of the same type of engine.
The engine explosion on Southwest Airlines flight 1380 on Tuesday was caused by a fan blade that broke off, the FAA said. The blast shattered a window, killing a passenger, in the first US passenger airline fatality since 2009.
"The unsafe condition," the FAA said in the order, "is likely to exist or develop in other products of the same design."
The inspections ordered are a sharp step-up from actions by both the European and US regulators after a Southwest flight in August 2016 made a safe emergency landing in Pensacola, Florida, after a fan blade separated from the same type of engine and debris ripped a hole above the left wing.
The European agency had given airlines nine months to check engines, while US regulators were still considering what to do.
Ultrasonic inspections on fan blades that have been used in more than 30,000 cycles, or in service for about 20 years, will be required in the next 20 days, the agencies said yesterday. A cycle includes one take-off and landing.
That order will affect about 680 engines globally, including about 350 in the US, the FAA said. The engine that blew apart on Tuesday's Southwest flight would have been affected, since the company said it had 40,000 cycles.
The coordinated 20-day measure partially resolves a gap in previous responses to the 2016 accident by the world's two largest and most influential aviation regulators, a person familiar with the discussions said and published documents show.
In August 2017 the FAA drafted an order giving airlines up to 18 months to carry out checks, but it had not finalised the measure by the time of Tuesday's fatal second accident.
The EASA had rejected a request by one airline to double the time allowed for checks to 18 months, matching the FAA's roll-out, saying data did not justify that.
The divergence marked a rare difference of approach between the two agencies, especially on one of the world's most-used aviation products. CFM, which is jointly owned by General Electric Co and France's Safran, produces the CFM56 engine in factories based both in the United States and in Europe.
"It happens that there are disagreements about the right way to go in some cases, and this was one of them," the person familiar with the discussions said.
On Tuesday, however, when news broke that a second failure had taken place involving the same model engine, aircraft and airline - this time killing a passenger who was partially pulled through a gaping hole next to her seat - the two agencies agreed to act quickly, the person said.
An FAA spokesman said the agency disputed that it had not agreed with European regulators on the response to the engine issue.
An EASA spokesman declined to comment.
