What happened
On February 1, 2017, a Cessna A188B agricultural aircraft, registration PR-NVC, was performing a takeoff from an unpaved landing strip at Fazenda Guarita, in Guaíba, Rio Grande do Sul. The mission involved the application of fungicide over a rice crop.
After accelerating along the length of the runway, the aircraft climbed only a few meters before losing lift and failing to maintain flight. The aircraft subsequently struck an irrigation canal located beyond the far end of the runway, causing the aircraft to overturn. The impact resulted in substantial damage to the engine, propeller, landing gear, and fuselage. The pilot sustained minor injuries.
The investigation
CENIPA's investigation focused on the aircraft's performance and the accuracy of the operator's weight and balance records. While the aircraft was within its maximum takeoff weight, investigators discovered that the center of gravity (CG) was significantly outside the manufacturer's established limits, exceeding the rear limit.
Discrepancies were found in the operator's weight and balance sheets; specifically, the arm values used for moment calculations differed drastically from those used by other operators of the same model. This error led to an incorrect calculation that suggested the CG was within limits when it was actually dangerously aft. Additionally, the pilot utilized a 30-degree flap setting for takeoff, which contradicted the aircraft manual's recommendation of a maximum 10-degree setting for restricted category operations, likely increasing drag and hindering performance.
Findings
- Improper Center of Gravity: The aircraft was operating with a center of gravity that exceeded the manufacturer's rear limit.
- Incorrect Weight and Balance Documentation: The operator's calculation methods used incorrect arm values, leading to inaccurate CG determination.
- Inappropriate Flap Configuration: The use of 30-degree flaps instead of the recommended 5 to 10 degrees increased aerodynamic drag.
- Pilot Judgment: Errors in flight preparation and takeoff configuration contributed to the loss of control.
- Management and Planning: Deficiencies in flight planning and managerial supervision were identified as contributing factors.