Event
On 25 August 2018, an Embraer EMB-195 operated by LOT Polish Airlines was conducting an international flight from Warsaw Chopin Airport (EPWA) to Lviv Danylo Halytskyi International Airport (UKLL). After takeoff, the flight crew requested clearance to climb to flight level (FL) 270. The air traffic controller initially cleared the aircraft to climb to FL 220 due to traffic and a turn for separation, then subsequently authorized further climb to FL 270.
During the climb, as the aircraft passed through FL 225, the crew reported that they needed to maintain FL 224, and the controller approved that level. Shortly thereafter, the crew requested a descent to FL 100. The descent was stopped at FL 170, and the crew declared that they would continue to the destination. However, after a few minutes, the crew changed their decision and declared a return to Warsaw. The aircraft landed at Warsaw at 11:48 UTC without further incident.
A post-flight inspection by maintenance personnel revealed that during the climb in icing conditions, the aircraft experienced a WING ANTI-ICE FAIL and a BLEED 2 FAIL (the latter had been dispatched under the Minimum Equipment List). These malfunctions led to an increase in cabin pressure. The crew decided to descend and return to Warsaw. After performing the appropriate checklists and exiting the icing conditions, the faults cleared. The crew submitted an Aviation Safety Report (ASR).
Probable Cause
The investigation determined that the cause of the incident was a malfunction of the bleed air system from engine No. 2 (BLEED 2 FAIL).
Operator Actions
The operator did not formulate any preventive actions following this incident. No safety recommendations were issued by the investigation authority.