What happened
On October 10, 2021, at 13:17 UTC, a McDonnell Douglas DC-9-82, registration YV3499, departed from Maiquetía International Airport in La Guaira, Venezuela, bound for Las Américas International Airport in the Dominican Republic. During the initial climb phase of the takeoff, the crew observed an "OIL STRAINER CLOGGING" warning light. Following the Quick Reference Handbook (QRH) procedures, the crew elected to return to the departure airport.
The aircraft was operating a commercial flight with 39 passengers and 9 crew members on board. There were no injuries reported, and the aircraft sustained no damage during the aborted departure. At the time of the event, the aircraft was carrying approximately 36,071 lbs of fuel.
The investigation
Investigators examined the aircraft's maintenance records and performed several technical inspections. The investigation included a photographic survey of the aircraft, interviews with the flight crew, and an inspection of engine #1 (LH) related to the oil pressure system.
Upon removing the oil filter from the LH engine, investigators found the presence of carbon deposits in all filter cells. Records indicated that this specific filter had been installed on October 7, 2021, during a gearbox replacement. Following the discovery, the oil and filter were replaced, and subsequent engine tests were completed successfully. A borescope inspection of the engine revealed only minimal, non-generalized erosion of the blades, which was within operational limits.
Findings
- The primary cause of the warning light was carbon deposits clogging the oil strainer in the number one (LH) engine.
- The filter involved had been recently installed as part of a gearbox replacement three days prior to the event.