What happened
On February 25, 2011, an EMB-820C Navajo, registration PT-ELY, was conducting a local instructional flight at the Arapongas aerodrome in Paraná, Brazil. During the third takeoff of the session, the crew noticed fluctuations in the RPM of the right engine while at an altitude of approximately 400 feet.
In response to the engine instability, the instructor pilot took control of the aircraft and shut down the right engine. The pilot then initiated a right-hand turn in an attempt to return to the active runway. However, the aircraft was unable to reach the airfield, forcing the crew to perform an emergency landing in a nearby sugarcane plantation. The aircraft sustained grave damage to both engines, propellers, wings, and the fuselage, while both the instructor and the student sustained light injuries.
The investigation
CENIPA's investigation focused on the mechanical state of the engines and the decision-making process of the crew. Technical examination of the right engine's turbocharger revealed that the turbine blades had been damaged due to the ingestion of metallic material, which caused the observed RPM fluctuations. Additionally, investigators found abnormal wear on two tappets and the camshaft lobes of the left engine, which likely reduced the engine's performance and compromised the aircraft's ability to maintain level flight on a single engine.
Regarding the crew, the investigation examined the instructor's actions and the lack of cockpit coordination. The investigation also looked into the organizational structure of the operator, noting a lack of standardized instructor training and formal evaluation processes for pilots performing instructional duties.
Findings
- The instructor demonstrated overconfidence and a low perception of danger, relying on past experiences rather than following established emergency procedures.
- The crew failed to consult the abbreviated checklist for engine failure during the emergency.
- There was a lack of cockpit coordination, as the instructor acted unilaterally without involving the student pilot in the emergency management.
- The right engine experienced RPM fluctuations caused by metallic debris ingestion in the turbocharger.
- The left engine's performance was likely compromised by abnormal wear on the camshaft components.
- The operator lacked standardized training programs for instructors and formal oversight for flight instruction processes.