U.S. airlines using General Electric Co. GEnx jet engines will be required to inspect their planes for signs of the type of flaws that led to a July explosion, the Federal Aviation Administration said.
Atlas Air Worldwide Holdings Inc., the only carrier flying the Boeing Co. jets with those engines, found nothing wrong on one of its 747-8 freighters yesterday and will inspect the other aircraft over the weekend, the FAA said in an e-mailed statement. A formal directive is being prepared, the FAA said.
The FAA plan heightened the scrutiny on the GEnx since a Boeing 787 Dreamliner spewed hot metal engine parts during a July 28 test in Charleston, South Carolina. There have now been three instances of damage to GEnx engines, which are used only on Boeing’s two newest planes, the 787 and the 747-8 jumbo jet.
“This now has entered the phase where it’s incumbent on GE and Boeing to come up very quickly with a very clear answer as to what the fix is, or they’re going to be hurting very badly,” Hans Weber, chief executive officer of aviation consultant Tecop International Inc., said in a telephone interview. “They’re now under real pressure.”
The FAA’s inspection directive followed a recommendation for the check from the U.S. National Transportation Safety Board, which investigates aviation accidents. Regulators worldwide typically follow the FAA’s lead in such cases.
“Because of the immediate threat of multiple engine failures on a single aircraft and the availability of an appropriate inspection procedure, there is an urgent need for the FAA to act immediately,” the NTSB wrote in a letter to the agency.
Hours later, the FAA said it “will continue to review the recommendations and coordinate closely with the NTSB and GE as part of the investigation.”
A similar GEnx engine crack was found last month on a twin-engine Dreamliner that hadn’t flown yet, according to the NTSB. A four-engine 747-8 flown by a Russian cargo carrier suffered an engine failure on Sept. 11 in China, and preliminary evidence shows it may have failed the same way as in Charleston, according to the NTSB.
Atlas is reviewing the notice from the NTSB, said Dan Loh, a spokesman for the Purchase, New York-based cargo carrier. Other airlines operating GEnx-equipped planes include Deutsche Lufthansa AG, the first airline to fly the 747-8 in passenger service. Most of the 747-8s in use are the freighter variant.
GE, the world’s largest maker of jet engines, said ultrasound inspections were almost complete on the engine part known as a fan mid-shaft that was blamed for the Charleston failure. The checks should be completed by early next week, said Rick Kennedy, a spokesman for Fairfield, Connecticut-based GE.
Boeing 787s and 747-8 passenger planes that use the engines have all been inspected, leaving only nine 747-8 freighters still to be reviewed, Jim Proulx, a spokesman for the Chicago-based planemaker, said in an e-mailed statement.
“There is some type of serious problem in either the design or the handling of this part,” Jim Wildey, the retired chief of the NTSB’s laboratory, said in an interview.
Unlike stress fractures, which grow gradually over time, the crack detected in the GEnx engine occurred much more quickly in the steel shaft’s microscopic crystals, Wildey said. It began where threads were cut into the shaft, making it weaker than the rest of the part, he said.
Investigators were lucky to have discovered a crack on an intact engine, which will let them examine it closely for potential problems, Wildey said. Evidence is frequently destroyed when an engine explodes, he said.
The GEnx-2B engine involved in the China incident, in Shanghai, will be sent to the U.S. to be taken apart “in a matter of days,” Kennedy said on Sept. 13. Visual checks after the incident found damage to the low-pressure turbine, with no breach of the casing, he said.
That episode involved a 747-8 freighter flown by AirBridgeCargo Airlines, a unit of Russia’s Volga-Dnepr Group and the country’s largest cargo carrier. The incident occurred before takeoff.
Boeing’s Dreamliner, the world’s first jetliner made chiefly of composite materials instead of traditional aluminum, uses either the GEnx-1B or engines from Rolls-Royce Holdings Plc. The GEnx is the only option on the 747-8, the latest variant of Boeing’s iconic hump-backed jumbo jet.
GE has delivered 10 GEnx-1B engines for the twin-engine Dreamliner and 108 GEnx-2B engines for the 747-8.
GE’s Kennedy said the NTSB inquiry in the initial Dreamliner incident has made significant progress. GE has introduced a new coating process to the affected part of new engines, he said.
“That would most likely indicate that there’s a corrosion problem, and the coating would mitigate against that,” said consultant Weber, a physicist and aviation-industry veteran who helped develop better part-testing techniques in the 1990s.