Incident Details
On 21 August 2016, a Bombardier DHC-8-400 operated by PLL "LOT" SA was conducting a flight into Warsaw Chopin Airport (EPWA). During the approach and while performing the APPROACH CHECKLIST, the crew noted a complete loss of hydraulic fluid from system No. 2. The PTU CONTROL FAIL amber lights illuminated, with no other warnings on the upper panel. The crew also observed the ENGINE 2 HYD VALVE CLOSED advisory light.
Sequence of Events
The flight crew followed the QRH procedures for No. 2 Hydraulic System Failure, Loss of All Fluid from No. 2 Hydraulic System (QRH 12.8) and Alternate Landing Gear Extension (QRH 14.3). A normal landing was executed, and the aircraft taxied to the parking stand. After the flight, an Air Safety Report (ASR) was filed, and the aircraft was handed over to maintenance.
Technical Findings
Maintenance personnel found contamination of engine No. 2 with hydraulic fluid. Inspection revealed a damaged hydraulic fitting on the pressure line of the No. 2 Engine-Driven Pump (EDP). This caused a loss of system pressure and fluid leakage. Since the No. 2 EDP had operated without fluid for some time, the decision was made to replace the pump. The hydraulic system was flushed and bled, and the EDP and PTU filters were replaced. A test of the primary landing gear extension and retraction system was completed successfully.
Probable Cause
The probable cause was identified as loss of hydraulic system seal due to damage to a fitting element.
Actions Taken
The operator recorded the event in the SMS database and classified it according to established criteria. It will be included in safety performance indicators monitored per the Safety Management Manual. The aircraft manufacturer was notified, and the EDP pump was sent for further investigation. No safety recommendations were issued.