Thursday, September 20, 2012

New GE Engines to Get Regular Checks

By ANDY PASZTOR, KATE LINEBAUGH and JON OSTROWER
The Wall Street Journal

U.S. aviation-safety regulators on Thursday announced relatively stringent requirements for inspections every 90 days of General Electric Co. engines installed so far on all Boeing Co.'s 787 and newest 747 models.

It is unusual for regulators to require such frequent ultrasound inspections of engines only recently approved for airline use.

The Federal Aviation Administration's decision, expected to become effective on Friday, follows urgent recommendations issued last week by the National Transportation Safety Board calling for enhanced inspections of GE's newest engine type, called GEnx. Citing cracked or fractured internal parts on three different engines since July, the board warned about the "threat of multiple engine failures on a single aircraft."

In its safety directive, the FAA similarly warned about preventing potential additional ruptures of the suspect shafts, which it said could result "in one or more" engine failures leading to "possible loss of the airplane."

The FAA previously telegraphed it planned to mandate enhanced inspections of GEnx engines. But in explaining its response to alleviate the hazard, the agency's latest statement said the "root cause is still somewhat unknown." The FAA also stressed that the shaft failures are "likely due to environmentally assisted cracking," which it described as a "type of corrosive cracking that is time-dependent."

Initial inspections have been completed on all 128 GEnx engines that have been delivered to customers and no further problems were found, GE said. "No GEnx-powered aircraft will be grounded for inspection," GE said.

Boeing said it has worked with GE to design inspections that can be completed during regularly scheduled maintenance and "not affect airline operations." The inspections will take up to three hours to complete and can be performed while the engine remains on wing.

To remedy the corrosion problem, GE is reverting to the coating on some internal parts that is used on its family of GE90 engines, from which the GEnx engine is derived. All future GEnx engines will use the coating and lubricant process used for the GE90, which has already been certified on other GE engines.

Calling the mandatory inspections "an interim action," the FAA document suggests replacement of some or all of the suspect parts with the old coating may be the ultimate solution.


Source:   http://online.wsj.com

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