What happened
On December 30, 2019, a Piper PA32-301T, registration HK2629, operated by Aerogalán, departed Palonegro Airport (SKBG) for a scheduled cargo flight to Cimitarra. Approximately six minutes after takeoff, the pilot requested to return to Palonegro for company reasons. Shortly thereafter, the pilot notified Air Traffic Control of an engine failure and stated an intention to land near a service station in Lebrija.
During the final approach, the pilot reported that the aircraft might not reach the runway and would instead attempt an emergency landing near a fuel station. Following the last communication, the aircraft disappeared from visual contact. A search was initiated, and a passing aircraft later spotted the wreckage 0.3 NM north of the reported location. The impact destroyed the aircraft, and all three fatalities (the pilot and two passengers) were confirmed at the scene.
The investigation
The GRIAA investigation focused on the mechanical integrity of the Lycoming TIO-540-S1AD engine. Investigators performed a detailed analysis of the crankshaft failure and examined maintenance records from the engine's most recent overhaul. The investigation included chemical analysis of the crankshaft material and an evaluation of the maintenance oversight procedures used by the operator and the authorized repair station.
Findings
- The primary cause of the accident was a failure of the crankshaft.
- The crankshaft exhibited signs of material aging, including surface erosion, discoloration, and cracks adjacent to the primary fracture.
- The overhaul process failed to identify these surface defects because visual inspections (Level 1 and 2) were not performed effectively.
- There was a lack of non-destructive testing (NDT) methods used to detect cracks during the engine overhaul.
- Maintenance records showed discrepancies, and the operator's procedures for inspecting and accepting engines after major service were deficient.