Incident Involving an Embraer ERJ-175 at EPWA

Incident Overview and Aircraft Details On July 7, 2016, an incident was recorded involving an Embraer ERJ-175 aircraft operated by PLL LOT SA. The event took place at the EPWA airport, specifically within the LOTAMS technical base. The incident was classified as an aviation incident, and no injuries were reported among the personnel or passengers. The investigation was supervised by Tomasz Makowski and concluded on August 22, 2016. ## Operational Context and Discovery The damage was identified during a periodic inspection of flap track wear. The inspection was conducted in accordance with a specific maintenance directive regarding wear found on the right wing inboard main flap track. During the procedure, which involved extending the flaps, LOTAMS maintenance personnel discovered damage to two pushrods associated with the fairing at the right inboard flap track 2A. ## Nature of the Damage The investigation documented two specific mechanical failures: * The upper pushrod, part number 171-03779-901, was found to be bent. * The lower pushrod, part number 171-03778-901, was broken, with its end joint (clevis) completely detached. The report noted that photographs of the flap mechanism cover and the damaged pushrods were not taken immediately after the fault was detected and before the parts were removed. This procedural gap prevented investigators from verifying the correctness of the components' installation. ## Maintenance Actions and Testing Following the discovery, the damaged pushrods were replaced in accordance with the Aircraft Maintenance Manual (AMM) 57-54-30-400-801-A, revision 41. Subsequently, functional tests were performed according to AMM 27-50-00-801-A, revision 41, and the tests were completed with a successful result. ## Contributing Factors and Historical Data The investigation team reviewed several operational circumstances that occurred prior to the incident: * A hard landing was detected on April 1, 2016, with a vertical acceleration of 2.23g at an aircraft weight of 30,822 kg and a landing speed of 123.25 knots. * An overspeed condition on the flaps was recorded on May 16, 2016, with an airspeed of 231.25 knots, detected by the Aerobytes system. * On July 6, 2016, the Aerobytes system detected significant longitudinal deceleration (-0.33G, compared to a normal -0.20G) during braking, which occurred simultaneously with a sharp left turn while the flaps were being retracted. A detailed analysis concluded that none of these individual events could be considered a sufficient cause for the incident. The report also referenced a similar incident involving an aircraft with registration SP-LIE on July 18, 2015, where the probable cause was attributed to the malfunction of the landing gear lateral vibration damper. ## Investigation Findings and Safety Actions The investigation was unable to establish a single, definitive cause for the incident. In response, the operator implemented several preventive measures: * The aircraft manufacturer was informed and reported that no similar cases had been recorded, noting that known analogous cases were associated with hard landings. * The incident was shared with the LOTAMS Technical Personnel Training section for use in periodic training on human factors and aircraft type. * The event was registered in the Safety Management System (SMS) database and classified according to PLL LOT SA criteria. It will be included in the Aviation Safety Indicators (SPI) monitored under the Aviation Safety Management Manual. No safety recommendations were issued by the commission.