What happened
On August 14, 2017, an EC 145 helicopter was performing a commercial repositioning flight from Zakopane to its home base in Pobiednik Wielki. At approximately 15:05 LMT, during the final approach phase of the landing at EPKP Kraków Pobiednik, the pilot observed a drop in oil pressure in the right engine.
Following the landing, the pilot notified the aircraft owner and the technical personnel of the maintenance organization, Heli Invest Services. The aircraft was immediately removed from service for inspection.
The investigation
Maintenance technicians performed an initial inspection of the electrical connections and the oil pressure sensor lines. To rule out sensor failure, the oil pressure and low-pressure warning sensors were swapped between the left and right engines; however, technical tests yielded negative results, meaning the issue persisted.
Further investigation was conducted in coordination with the engine manufacturer, Turbomeca. Following specific instructions from the manufacturer, a series of technical procedures were carried out to allow the helicopter to be safely repositioned to the Heli Invest Services maintenance base in Warsaw. After performing additional verification steps as directed by the manufacturer, the source of the pressure drop was identified.
Findings
- The investigation determined that the damaged gasket on the oil filter drain valve in the right engine was the probable cause of the low oil pressure.
After the replacement of the gasket and successful follow-up testing, the oil pressure in the right engine returned to normal parameters, and the aircraft was returned to service.