What happened
On August 11, 2011, a Cessna 206G, registration PT-XCG, was performing a routine cargo flight to transport food and medicine to the Onkiola indigenous village in Roraima, Brazil. The flight, operated by Roraima Táxi-Aéreo Ltda., departed from Auaris Aerodrome (SWBV) with only the pilot on board.
Upon arrival at the Onkiola landing site, the pilot performed a low pass to inspect the runway conditions. The landing strip, which was unrecorded and unregistered, measured approximately 400 meters by 16 meters. During the landing roll, the pilot was unable to maintain control of the aircraft and failed to stop before the end of the runway. The aircraft overran the threshold, traveling 15 meters beyond the runway before striking a depression in the terrain. The impact caused severe damage to the nose gear, propeller, and engine, though the pilot remained uninjured.
The investigation
CENIPA's investigation focused on the operational risks associated with using unregistered landing strips and the environmental conditions at the time of the accident. Investigators noted that while the pilot had sufficient experience and valid certifications, the landing strip was a dirt surface that had become wet. Although the pilot performed a reconnaissance pass, the investigation established that a single pass is often insufficient to detect surface moisture.
Technical analysis of the aircraft's performance manual indicated that while a standard ground roll for a short landing is approximately 253 meters, the manual requires a 40% increase for grass runways. However, the investigation found that these calculations did not account for the increased stopping distance required on a wet dirt surface. Furthermore, discrepancies were found in the operator's ANAC-approved manuals, which contained conceptual errors regarding takeoff and landing directions on sloped runways.
Findings
- The pilot's decision to land on a short, wet, and unregistered dirt strip contributed to the occurrence.
- The operator failed to provide adequate managerial supervision regarding the risks of flight assignments to unregistered aerodromes.
- The braking application may have been delayed, contributing to the overrun.
- The lack of specific performance data for wet dirt surfaces made it difficult to accurately estimate the required landing distance.
- The regulatory deviation granted by ANAC for operating at unregistered strips was insufficient to mitigate the inherent risks of the location.