What happened
On November 24, 2014, during routine monitoring at Warsaw Chopin Airport (EPWA), maintenance personnel identified abnormal engine performance trends on an Embraer 175, registration SP-LIF, operated by PLL LOT S.A. Analysis of engine data from the preceding days showed an increase in Exhaust Gas Temperature (EGT) and a slight rise in fuel flow on the right engine (ESN 193449).
Due to previous similar incidents involving other aircraft in the fleet, the airline's technical department ordered a borescope inspection (BSI). The inspection confirmed that the engine had sustained internal damage due to rotor-stator contact, specifically identifying damage to the STG5 high-pressure compressor (HPC) that rendered the engine unserviceable. The engine was subsequently replaced, and the manufacturer, GE, was notified.
The investigation
The investigation focused on the technical cause of the engine degradation and the effectiveness of the airline's monitoring systems. The inquiry examined engine data trends, borescope inspection results, and the history of similar occurrences within the Embraer fleet operated by the airline. The investigation also reviewed the procedures for data transmission from the aircraft's ACARS system to the engine manufacturer's servers.