Hydraulic Leak Incident Involving a Bombardier DHC-8-402 at LJLJ (SP-EQE)

Incident Overview and Initial Findings On 5 May 2017, at approximately 14:50 UTC, the crew of a Bombardier DHC-8-402 detected traces of hydraulic fluid leaking from the engine number 2 nacelle while conducting a pre-departure check at LJLJ. Following an engine run-up, the leak was observed to increase. The flight was subsequently cancelled, and technical services were notified. ## Investigation and Maintenance Actions Because contracted technical support was unavailable at LJU, a technical team was dispatched from EPWA. Upon arrival, the team inspected the engine nacelle and found overfilled bottles in the hydraulic fluid expansion tank, along with two loose hydraulic line connections. The lines were tightened in accordance with AMM 29-11-31 REV.57, and the expansion tank bottles were cleaned. A test conducted per AMM 29-10-00 REV. 57 was passed, and the aircraft was re-based to its home base. ## Final Determination and Outcome After arriving at EPWA, technical services again detected signs of a hydraulic leak. To identify the source, the engine exhaust pipe had to be removed. Inspections revealed a chafed hydraulic line between the hydraulic fluid reservoir and hydraulic manifold number 2. The damaged line was repaired in accordance with AMM RYNGLOK UNION 20-2041-350-801 REV. 57, and a leak test of the system was completed without findings. The aircraft was returned to service. The incident was recorded in the SMS database and classified according to the operator's criteria. The direct cause of the incident was the chafed hydraulic line. The investigation was supervised by Andrzej Bartosiewicz and concluded on 13 March 2018. No safety recommendations were issued.