What happened
On November 25, 2024, an Agusta A109E helicopter, registration LV-CLC, was performing a non-commercial flight from Club de Polo La Dolfina in Cañuelas to the Helicópteros Marinos helipad in Don Torcuato, Argentina. During the cruise phase of the flight, the pilot noticed an intermittent "WARNING" alarm accompanied by a "PRESS OIL" indication. This warning soon became a continuous indication.
In response to the engine system warning, the crew declared an emergency and executed an unplanned landing in an unprepared field. There were no injuries and no damage to the aircraft during the landing.
The investigation
Following the incident, the aircraft was inspected at the landing site. Investigators verified the installation of the main transmission oil pressure switch and transducer, finding that the connectors were correctly seated. No oil leaks were detected, and oil levels were found to be at the maximum established values. The aircraft was subsequently flown via ferry flight to an aeronautical repair workshop.
During maintenance at the workshop, technicians observed that the "XMSN OIL PRESS" indication on the instrument panel failed to appear when the aircraft was energized. Upon disconnecting the connector associated with the switch, investigators discovered dirt between the connector pins. The contacts were cleaned, and maintenance was performed in accordance with the manufacturer's maintenance manual regarding the oil pressure warning circuit.
Findings
- The primary cause of the oil pressure warning was the presence of contamination (dirt) between the pins of the electrical connector.
- The aircraft's oil levels and transmission components were found to be within operational limits, with no leaks present.