A day after the dangerous explosion of an engine on United Airlines flight 328 shortly after takeoff from Denver, the older Boeing 777-200 models involved were effectively grounded worldwide.
The Federal Aviation Administration (FAA) ordered immediate stepped-up inspections of Boeing 777-200 airplanes equipped with certain Pratt & Whitney engines on Sunday, as airlines operating such jets in the U.S. and Japan suspended flights.
United Airlines grounded 24 similar 777s, while the Japanese aviation regulator ordered all planes equipped with this type of engine to cease flying in Japan until further notice.
Boeing followed late Sunday with a statement that "recommended suspending operations of the 69 in-service and 59 in-storage 777s powered by Pratt & Whitney 4000-112 engines until the FAA identifies the appropriate inspection protocol."
The speed and decisiveness of the grounding of the jets is spurred by the fact that there have been two previous engine blowouts on similar 777s with the same Pratt & Whitney engine.
Another United flight suffered a similar engine failure three years ago, and it happened again on a Japan Airlines 777-200 in December.
These are older 777 airplanes. All 777s built since 2004 are powered exclusively by GE-90 engines.
FAA Administrator Steve Dickson in a statement said that he directed his team "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 his agency's experts "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."