Incident Overview
On 8 July 2011, at approximately 09:30 local time, a Follow-Me vehicle crew at Warsaw Chopin Airport (EPWA) discovered aircraft parts on taxiway M2. Consultation with LOT Maintenance mechanics identified the parts as elements of the landing gear brake assembly from an Embraer ERJ-175. The information was immediately relayed to air traffic control.
Subsequent Findings
At 10:50 local time, the Follow-Me crew reported that after the arrival of LOT flight LO3851 from Wrocław (EPWR) on aircraft SP-LIL, mechanics found deficiencies in the brake assembly: out of 16 elements, only 11 were present. The airport operations officer (DOP) forwarded this information to their counterpart in Wrocław, requesting a check of the parking area. No additional parts were found.
Pilot Statement
The captain of the aircraft stated that he performed the flight LO3851 on 8 July 2011. Before departure from Warsaw, he conducted a pre-start inspection and noted no abnormalities. Brake assembly temperatures were within normal green ranges, with a temperature difference between left and right struts of about 100°C, which he considered normal (e.g., after crosswind landings). During taxi, takeoff, and landing in Wrocław, no anomalies were detected. After landing in Warsaw, he performed a post-flight inspection and found no issues. He was later informed by a mechanic that several brake assembly elements from the left main landing gear were missing.
Maintenance Findings
During maintenance, mechanics found damaged brake assemblies No. 1 and No. 2 along with their corresponding wheels. The damaged brake assemblies and wheels were replaced.
Brake Assembly Manufacturer and Actions
The brake assemblies used on ERJ 170/190 aircraft are manufactured by Meggitt (formerly ABSC). As of the report, the manufacturer had not developed any modification to address the issue, but had issued service bulletins recommending additional inspections. LOT Polish Airlines implemented the following measures:
- For the ERJ 190 fleet: Engineering Order EO SLOT/E90/0052/11, incorporating inspections per SB 90002340-32-04 and SB 90002340-32-05 every 600 flight hours.
- For the ERJ 170 fleet: Engineering Order EO SLOT/E70/0034/11, incorporating inspections per SB 90000583-32-03 and SB 90000583-32-04 every 600 flight hours.
- Line Maintenance Instruction 2110 was updated with inspection cards for movable disc locks, and a new card for parking preparation inspections.
- Two Engineering Letters/Service Information Bulletins (EL/SIB/001/11 and EL/SIB/001/12) were issued based on EASA SIBs.
Context of Incident
This incident occurred during the period when the Improved Go-Around Procedure (IGAP) was in effect (15 April 2011 to 6 March 2012), which resulted in higher approach and landing speeds. After the IGAP procedure was withdrawn via Operational Bulletin No. 02/2012, brake assembly life issues ceased, and post-March 2012 incidents of brake assembly damage were sporadic.
Investigation Outcome
The Polish State Commission for Aircraft Accident Investigation (PKBWL) did not receive additional data on the incident. Due to a lack of investigation results and notification from LOT that reports are retained for no more than five years, the PKBWL closed the investigation without determining the cause.