The National Transportation Safety Board says it will likely be months before a formal cause is established for Friday’s incident involving an engine explosion on an American Airlines 767 at O’Hare.
The aircraft suffered what is termed an “uncontained engine failure” as it had just begun its takeoff roll for a flight to Miami. A total of 161 passengers and 9 crew members were safely evacuated during the ensuing fire.
“Examination of the engine has revealed that the stage two disk of the high pressure turbine failed,” said NTSB investigator Lorenda Ward, noting that one piece of that disk crashed through the roof of a UPS facility more than half a mile from the aircraft.
The engine which exploded on that aircraft was a General Electric CF6, part of a workhorse family of engines which GE notes have logged more than 400 million hours in the air since their introduction in the early eighties. The specific engine, a CF6 80 series, has more than 200 million successful hours in the air.
But there have been other incidents.
In September of 1997, a Canadian Airlines jetliner suffered a similar engine failure in Beijing. Three years later, a Varig Airlines 767 with 178 passengers aboard experienced a fire in Sao Paulo Brazil.
A US Airways 767 experienced an uncontained engine failure with a similar engine during a ground test in September of 2000. Air New Zealand had a failure in December of 2002, and another American Airlines 767 had an engine explosion at Los Angeles International Airport in June of 2006.
All of those involved stage one disks, and after the Los Angeles incident, the FAA mandated the inspection, and if necessary, reworking of the high-pressure turbine components at 6900 cycles or more. The NTSB went a step further, urging inspection if the engines were in service for more than 3,000 cycles.
Aviation attorney Floyd Wisner, who represented clients involving the failure of a different model of GE engine on a flight in Las Vegas, suggested the Chicago incident points to the need for new inspections.
“They need to look into the possible fatigue stresses on the high compressor system of this engine and other engines like it,” he said. “What if something like this happened in flight?”