What happened
On September 22, 2001, a Britten-Norman BN-2A-27, registration PT-KTQ, departed from Rio Branco, AC, bound for Santa Rosa do Purus, AC. The flight, operated by the Centro de Trabalho Indigenista, was carrying a pilot and four passengers on a mission to overfly isolated indigenous areas.
Approximately 30 minutes into the flight, a passenger noticed and alerted the pilot to an oil leak emanating from the left engine cowling. The pilot decided to return to the origin airport. During the return, the left engine parameters reached operational limits. In response, the pilot feathered the propeller and shut down the left engine.
While attempting to continue the flight as a single-engine aircraft, the pilot observed rising temperatures in the right engine and was unable to maintain level flight. Despite instructions to the passengers to jettison cargo, the pilot determined that the destination was unreachable and performed a forced landing at Fazenda Colorado. Upon impact, the aircraft struck a wire fence, causing the landing gear to collapse and resulting in severe damage to the airframe. The pilot and all four passengers sustained minor injuries.
The investigation
CENIPA's investigation focused on the mechanical failure and the maintenance history of the aircraft. Investigators found that the aircraft's logbooks were outdated, meaning recent maintenance and inspection intervals were not properly documented.
Technical analysis revealed that a propeller seal on the left engine had been replaced with a non-original part, and adhesive was used to ensure a seal, which deviated from the manufacturer's recommended procedures. Furthermore, the investigation examined the operational oversight of the operator, noting a lack of systematic flight personnel monitoring and maintenance management.