What happened
On September 11, 2013, a Cessna 152, registration PR-JBA, departed from the Maricá Aerodrome (SDMC) for a local flight instruction mission. The aircraft was occupied by an instructor and a student pilot. Shortly after takeoff, the engine experienced a significant loss of power, followed by a complete engine failure in flight.
In an attempt to perform an emergency landing, the instructor directed the aircraft toward a street in the center of Maricandum. During the descent, the aircraft's left landing gear struck electrical wires, causing the plane to yaw to the left and pitch toward a residential property. The aircraft subsequently struck a garage gate and a concrete wall. The impact was severe enough to break the fuselage in half. The instructor sustained fatal injuries at the scene, while the student pilot suffered serious injuries.
The investigation
CENIPA's investigation focused on the mechanical failure of the Lycoming O-235-L2C engine and the maintenance history of the aircraft. Investigators examined the engine components and discovered that the failure was caused by the fracture of the exhaust valve head in cylinder number 3. This fracture caused the valve head to penetrate the piston head, leading to the engine seizing.
Technical analysis of the engine revealed several maintenance irregularities. Investigators found that the engine contained non-original intake and exhaust guides, and two cylinders were incorrectly marked with the same number (number 3). Additionally, the engine's identification plate was improperly attached, and non-recommended adhesive had been used to seal the engine block. The investigation also noted that the flight school's operating authorization had been suspended by ANAC at the time of the accident.
Findings
- Inadequate maintenance of the engine, specifically the failure to comply with Mandatory Service Bulletin (SB) 368, which requires periodic inspection of exhaust valves and guides to prevent carbon buildup and subsequent valve failure.
- Deficient maintenance practices, including the use of non-original parts, improper cylinder numbering, and the use of unapproved sealants.
- Organizational culture failures within the flight school, characterized by a lack of adherence to established aeronautical procedures and a lack of management oversight.
- Lack of maintenance oversight, which prevented the timely identification of critical safety issues regarding the aircraft's airworthiness.