Airbridge Cargo B748 near Hong Kong on Jul 31st 2013, both left hand engines surged at same time, one right hand engine damaged

Incident

An Airbridge Cargo Boeing 747-800, registration VQ-BGZ performing freight flight RU-349 from Moscow Sheremetyevo (Russia) to Hong Kong (China), was enroute at FL410 about 80 minutes prior to estimated landing when both left hand engines (GEnx) surged simultaneously, engine #2 (inboard) temporarily shut down and auto-started again. The aircraft continued to Hong Kong for a safe landing on all 4 engines about 80 minutes later.

Rosaviatsia reported on Aug 6th 2013 that the aircraft entered a zone of dramatic temperature fluctuations, the temperature changing between -53 and -33 degrees C, when the engines surged, #2 spontaneously shut down and auto-started again without crew intervention. Both engines received damage to high pressure compressor blades.

In a safety message to operators released on Aug 20th 2013 Rosaviatsia rated the occurrence a "very serious incident" reporting that engines 1,2 and 4 were affected. Ice accumulated on unheated parts of the high pressure compressor in unpredictable and poorly understood meteorological conditions leading to the disruption of air flow inside the engine causing surges of the left hand engines. The flight was continued to destination, a post flight examination showed "unacceptable damage" to the high pressure compressor blades of engines 1,2 and 4 (both left and outboard right hand engine). Rosaviatsia is investigating the occurrence together with Boeing and General Electric, the FAA and EASA have been notified about this very serious incident.

On Nov 25th 2013 Boeing confirmed that a Multi-Operator-Message (MOM) has been sent to B747-8 and B787-800 customers, "who operate some GE-powered engines after instances of ice crystal icing that resulted in temporary diminished engine performance. To reduce chances of ice crystal conditions, Boeing also updated its Airplane Flight Manual (AFM) to prohibit flight within 50 nautical miles of large convective weather systems that may contain ice crystals. Boeing is working with its customers and GE to address the icing issue. Only a small number of GEnx engines have experienced the ice crystal icing issue in flight. GE will introduce the improvements necessary to return the engine to expected performance levels. Boeing is disappointed in any impact this situation may have on our customers, as is the GE team. We, like our customers, expect the delivered product to meet all expectations and will work closely with GE to address the subject condition. We regret the business disruption this will cause for our customer and remain ready to provide whatever assistance we can to Japan Airlines."

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Źródło: avherald
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