What happened
On October 16, 2016, a Piper PA-23-250D, registration OB-2039, operated by Global Mapping S.A.C., was performing a repositioning flight from Trujillo to Lima with a technical stop in Chimbote. The crew, consisting of a pilot in command, a co-pilot, and two mechanics, had departed Trujillo (SPRU) and climbed to 13,000 feet.
While cruising approximately 60 nautical miles from Chimbote, the crew observed a drop in left engine manifold pressure to 20 inches of mercury, accompanied by rising oil temperatures, white smoke from the engine, and an oil leak. The crew declared an emergency and requested an approach to Chimbote Airport (SPEO). To maintain control, the crew shut down the left engine and successfully landed the aircraft at 21:15 UTC.
The investigation
The CIAA investigation focused on the mechanical failure of the engine components and the maintenance records of the operator. Investigators examined the left engine's turbocharger and the surrounding induction system. The inspection revealed that a portion of the baffle assembly flange had broken off and been ingested by the compressor. This ingestion caused severe damage to the compressor wheel and the subsequent failure of the compressor-turbine shaft, which resulted in the loss of the turbine wheel.
Additionally, the investigation scrutinized the aircraft's maintenance logs. It was discovered that the aircraft was not in an airworthy condition for the scheduled flight, as a required 100-hour inspection had not been performed or documented. The investigation also found discrepancies in the maintenance records, including unrecorded 50-hour inspections and improperly recorded calendar-based inspections.
Findings
- The primary cause of the incident was the sudden failure of the left engine's turbocharger caused by the ingestion of a metallic section from the air induction baffle flange into the compressor.
- The aircraft was not in an airworthy state due to the failure to perform and document a mandatory 100-hour inspection.
- Maintenance records for the operator showed inconsistencies, including unrecorded 50-hour inspections and improper entries for 7-day and 30-day calendar inspections.
- The maintenance program (PIA) lacked specific, detailed instructions regarding the inspection depth and scope for the turbocharger induction and exhaust components.