Background
The flight departed Maringá Airport at 1837 LT, bound for São Paulo, with four passengers and one pilot on board. The aircraft was a twin-engine type. The pilot had recently earned technical qualification in the aircraft type.
Flight and Accident
Approximately 35 minutes into the flight, about five minutes after reaching its assigned altitude of 21,000 feet, the aircraft stalled and entered an uncontrolled descent. The pilot was unable to regain control, and the aircraft partially disintegrated in the air before crashing in a flat attitude in a field. The aircraft was destroyed, and all five occupants were killed.
Investigation Findings
The investigation identified the following factors:
- The captain did not promptly identify the stall, which may have deprived him of handling the controls according to emergency procedures, contributing to an abnormal attitude.
- The captain's attention was focused on passengers in the rear seats, reducing situational awareness and hindering stall identification.
- The copilot functions were assumed by a person lacking proper professional formation and qualification, and prescribed procedures, including checklist use, were not performed.
- Cockpit voice recorder (CVR) recordings confirmed icing conditions. The selected flight level (FL210) created conditions favorable to severe icing on the aircraft structure. The captain did not activate the Ice Protection System as required by the flight manual.
- The aircraft's rotation after stalling may have caused loss of balance references (vestibular system), preventing the captain from associating the turn direction with corrective actions.
- The captain did not adhere to aircraft checklists and deliberately used non-prescribed procedures (disarming the starter and "seven killers").
- The captain selected an inappropriate flight level for the route and rejected a higher flight level offered.
- The captain used a checklist not prescribed for the aircraft, which may have influenced his actions.
- The captain's recent technical qualification, inattention, distraction, and non-compliance with procedures contributed to poor situational awareness.
- The flight plan was submitted via telephone, so the captain's awareness of route conditions could not be determined. Selecting a freezing level along a moving front indicated inappropriate planning.
- The investigation could not determine the captain's overall experience or whether his IFR experience was sufficient, given his decisions contrary to best practices.
- Lack of monitoring or supervision of the captain's activities allowed unsafe behaviors and attitudes.
- There was an apparent lack of effective managerial supervision by the aircraft operator regarding the captain's actions and aircraft problems.
Probable Cause
The probable cause includes the following factors: lack of prompt stall identification by the captain; the captain's focus on passengers reducing situational awareness; complacency in allowing an unqualified person to assume copilot functions; flying under icing conditions without activating the Ice Protection System; inappropriate flight level selection; non-adherence to prescribed checklists; use of non-prescribed procedures; recent qualification and inattention; inadequate flight planning; lack of supervision by the operator.