Incident Overview
On March 23, 2016, at 16:40 local time, a Learjet 31A, registration LV-BSO, was operating a flight from San Fernando Airport (SADF) to Laguna del Sauce International Airport (SULS), Uruguay. The aircraft carried two pilots and seven passengers. During the descent phase, the flight crew observed a slow and progressive decrease in the hydraulic fluid level.
Actions Taken
Upon noticing the hydraulic fluid loss, the crew immediately performed the appropriate checklists for such an irregularity. The aircraft continued its approach and landed normally on runway 26. After exiting the runway, the crew stopped the aircraft on taxiway B as a precautionary measure. All passengers were uninjured, and the aircraft sustained no damage.
Inspection Findings
A post-flight inspection revealed a hydraulic fluid leak in the nose gear housing area. A qualified mechanic verified that there was no leak in the landing gear down line. The aircraft was subsequently dispatched on a ferry flight back to SADF with the landing gear extended and locked, where corrective maintenance was performed at an authorized facility. Upon further inspection, the leak was determined to originate from the rigid pressure line for the "gear up" circuit in the nose gear actuator. The rigid line was removed and the nozzle was repaired in accordance with Advisory Circular AC 43-13B.
Probable Cause
The probable cause was identified as hydraulic fluid loss from the rigid pressure line for the "gear up" circuit in the nose gear actuator.