What happened
On December 15, 2015, a Cessna A-188, registration HK2277, was performing agricultural spraying operations over a rice crop in Pueblo Nuevo, Magdalena. The aircraft, operated by FASE S.A.S., had completed seven passes over the field when, during a climb, a violent explosion occurred in the engine area. The event was accompanied by heavy smoke and fire.
Following the explosion, the aircraft attempted to invert, but the pilot maintained control and executed a controlled emergency landing on unprepared terrain. During the landing roll, the aircraft crossed a depression and struck a 3-m tall tree with its left wing, causing a sudden change in direction. Although the pilot successfully evacuated the aircraft uninjured, a fire intensified, eventually consuming approximately 80% of the airframe. The aircraft was destroyed.
The investigation
The GRIAA investigation focused on the mechanical failure and the regulatory compliance of the operation. Investigators examined the engine, the propeller hub, and the maintenance records of the aircraft. The investigation revealed that the propeller had detached from the engine crankshaft during flight.
Physical evidence at the scene showed that the propeller hub had suffered significant damage. Specifically, two of the five bolts required to secure the propeller to the crankshaft had fractured due to material fatigue and excessive mechanical loads. Furthermore, investigators found evidence suggesting that the propeller had been improperly installed during a previous 200-hour service, as several mounting nuts were missing, leaving only two bolts to bear the centrifugal and mechanical forces.
Findings
- The primary cause of the accident was the separation of the propeller during a low-altitude climb, resulting from material fatigue and excessive stress on the mounting bolts.
- The propeller was improperly installed, with only two of the five required bolts securing the propeller to the crankshaft.
- The operator failed to supervise operations, allowing the flight to proceed despite the aircraft having a suspended airworthiness certificate and an expired registration.
- The pilot operated the aircraft with an expired medical certificate and an expired annual proficiency check.
- The flight was not officially scheduled or supervised by the company, having been organized based on instructions from the aircraft owner.
- The aircraft was operating from an unauthorized airstrip that lacked official operating authorization.