What happened
On August 21, 2015, a private Cessna T210, registration HK4788G, was performing a flight from Cartagena to Ibagué when the crew experienced a partial loss of engine power. Approximately 84 minutes into the flight, while cruising at 11,500 feet near Caucasia, Antioquia, the engine exhibited abnormal vibrations and a drop in RPM.
In response to the engine anomaly, the pilot initiated an emergency descent to perform a precautionary landing at the nearest available airfield, El Tomín (SKEB). During the landing on runway 01, the aircraft failed to stop within the runway limits, overshooting the end of the runway and crossing the threshold of runway 19. The aircraft eventually came to a stop in a public road adjacent to the aerodrome after striking a perimeter fence and bushes. All three (3) occupants were able to evacuate the aircraft uninjured, though the aircraft sustained significant damage to the nose gear, propeller, engine cowlings, and left wing.
The investigation
The GRIAA investigation focused on the mechanical failure of the Continental TSIO-520R engine and the flight parameters during the emergency landing. Investigators performed a teardown of the engine at a certified workshop to examine the internal components.
Technical analysis revealed that the cylinder located in position No. 6 had suffered a sudden fracture between the ninth and tenth cooling fin stages. The investigation also scrutinized the maintenance records of the engine, specifically looking for compliance with mandatory service bulletins and the traceability of installed components. Furthermore, the investigators evaluated the pilot's operational procedures and the stability of the approach during the emergency phase.
Findings
- The primary cause of the power loss was a thermal fatigue fracture in the No. 6 cylinder, resulting from a manufacturing defect that left the component unable to withstand standard temperature fluctuations.
- The failure was exacerbated by the cylinder's position (No. 6), which receives direct airflow from the aircraft nose, accelerating thermal stress.
- A mandatory service bulletin, MSB 06-2, had not been implemented during the engine's last overhaul, which prevented the timely detection of the defective cylinder.
- The runway excursion was caused by an unstable approach and a deep landing, as the pilot maintained excessive speed and altitude during the emergency descent.
- The pilot lacked the necessary ground training/course for this specific aircraft type, contributing to a lack of familiarity with certain operational procedures and parameters under emergency conditions.