On September 30th, 2017, Air France Flight 66 was heading from Paris Charles de Gaulle Airport to Los Angeles International Airport. However, the Airbus A380 suffered an uncontained engine failure. Therefore, it made an emergency landing at Goose Bay Airport, Canada. A report shared today by the Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) has now concluded that this failure was caused by a lack of scientific understanding about the alloy used for the plane’s engine parts.
Under scrutiny
Registration F-HPJE was carrying 497 passengers and 24 members of Air France’s crew around this time three years ago when the incident happened. The aircraft’s engine number four then failed with an explosion after five hours in the air. Subsequently, the plane landed 150 kilometres (90 miles) southeast of Paamiut, Greenland. There were no fatalities during the event.
AeroTime reports that examiners noticed that the first rotating fan assembly at the front of an engine and the air inlet, along with the fan case had separated mid-flight. This caused minor structural damage to the superjumbo. Altogether, it has taken 21 months for investigators to piece all the information together until now.
The specifics
The GP7200 engine was produced by Engine Alliance, which is a consortium of General Electric and Pratt & Whitney. The outfit used titanium alloy Ti-6-4. During their time, the scientific community was not familiar with the alloy’s susceptibility to cold dwell fatigue. Above all, the researchers affirm that Airbus is not at all at fault in regards to this incident.
AeroTime highlights that plane engine metal alloys are often expected to perform at over 300˚C (572˚F). Although if the motor works at a lower temperature than that, there can be ‘cold’ dwell fatigue. This factor considerably reduces the expected engine cycles to failure.
So, during this incident in 2017, the engine failed after 3,544 flight cycles. Yet the estimated minimum life of the titanium part was 15,000 cycles.
Going forward
Altogether, the Ti-6-4 alloy was not considered sensitive to cold dwell fatigue up until the failure of this A380’s engine number 4 fan hub. Regardless, both the European Union Aviation Safety Authority (EASA) and the Federal Aviation Administration (FAA) have now been told to ensure that the design, sizing, and manufacturing criteria for Ti-6-4 alloy engine parts are revised. Additionally, they should adopt a new in-service inspection program to detect possible indications of cold dwell fatigue in regards to these alloys.
What are your thoughts about what caused Air France’s Airbus A380 uncontained engine failure? Are you surprised about these findings by the Bureau of Enquiry and Analysis for Civil Aviation Safety? Let us know what you think of the situation in the comment section.
