What happened
On September 29, 2019, an Embraer ERJ190-100IGW, registration LV-CIG, operated by Austral Líneas Aéreas, departed Aeroparque Jorge Newbery in Buenos Aires for Salta. During the initial climb phase of the flight, while passing through 3,800 feet, the aircraft experienced a failure of the left engine.
Upon detecting abnormal engine parameters, the crew declared a MAYDAY emergency and initiated a return to the departure airport. The aircraft completed the approach and landing using only one operational engine. There were no injuries among the 60 passengers and 5 crew members on board, though the left engine sustained significant damage due to the separation of turbine blades.
The investigation
The investigation focused on the mechanical failure of the General Electric CF34-10E5A1G08 engine. Technical analysis of the components revealed that the high-pressure turbine disk possessed a geometric profile that deviated from the intended design. This manufacturing irregularity reduced the clearance between the contact surfaces of the turbine blades and the disk, leading to an uneven distribution of mechanical loads.
Investigators examined the maintenance history and operational parameters of the aircraft. While the operator's engine performance parameters were noted to be higher than some other operators, the investigation confirmed that all values remained within approved operational limits and that the airline adhered to all airworthiness requirements. The engine components, including the blades and disk, had been installed in the engine since new.
Findings
- The primary cause of the engine failure was a manufacturing defect in the high-pressure turbine disk and blades produced by XAE.
- A geometric discrepancy in the disk profile caused a concentration of stress due to inadequate clearance between the blade and disk surfaces.
- This stress concentration led to the failure of the turbine blades under normal operating temperatures and pressures.
- The defect was a latent condition that could not be detected through standard maintenance or inspection protocols available at the time of the event.