What happened
On June 7, 1997, a Rockwell AC6T Turbo Commander, registered PT-OFG, departed from Bacacheri, PR, on an IFR flight plan destined for Joinville, SC. During the flight, the crew requested to cancel the IFR plan and proceed under visual flight rules. Shortly after, the aircraft crashed near Garuva, SC.
Witnesses observed the aircraft breaking into three parts while on fire, with the debris falling vertically over the mountains north of Joinville. The impact and subsequent fire resulted in 5 fatalities (two pilots and three passengers) and the total destruction of the aircraft.
The investigation
CENIPA investigators examined the wreckage, specifically the tail cone and wing roots, as the rest of the aircraft was heavily destroyed by fire. Laboratory analysis by the Institute of Aeronautics and Space (IAE/CTA) determined that the components did not show pre-existing cracks but had failed due to structural overload. Evidence from the right wing root suggested that the fire or an explosion originated in that area.
The investigation also reviewed the flight's operational parameters. The pilot had filed a flight plan with a cruise speed of 260 knots, which significantly exceeded the manufacturer's recommended maximum speed of 149 knots for turbulence penetration. At the time of the accident, the aircraft was maintaining an average speed of approximately 193 knots, and further acceleration was likely attempted to break a personal speed record for the route.
Meteorological data confirmed that while visibility was good, significant turbulence was present in the region, a common occurrence during the winter months. Additionally, the investigation noted that the company's meteorological monitoring equipment was malfunctioning, which may have prevented the issuance of turbulence alerts.
Findings
- Structural failure caused by aerodynamic loads exceeding the aircraft's design limits during flight in turbulence.
- High-speed operation exceeding the manufacturer's recommended turbulence penetration speed of 149 knots.
- Human factors, specifically the pilot's competitive drive to break a personal speed record.
- Lack of organizational oversight, as the aircraft operator lacked a structured system to supervise flight operations and pilot performance.
- Inadequate Crew Resource Management (CRM), potentially exacerbated by interpersonal tensions between the crew members.
- Adverse meteorological conditions, specifically the presence of turbulence in the area.