What happened
On July 10, 2015, a Britten Norman BN-2A-7, registration PT-DYL, was performing a cargo and passenger transport flight from Teresina (SBTE) to Fortaleza (SBFZ). While descending through 3,0-00 feet for landing, the aircraft's right engine lost power. The pilot attempted to follow emergency checklist procedures to restore power but was unsuccessful.
Recognizing the loss of performance in single-engine configuration, the pilot decided to perform an emergency landing in an open field at Fazenda Lagoa dos Porcos, approximately 11NM from the destination. The aircraft landed on irregular terrain covered in tall grass, resulting in substantial damage to the auxiliary landing gear and the right main gear strut. All four occupants—the pilot and three passengers—were uninjured.
The investigation
CENIPA investigators examined the fuel and propulsion systems to determine the cause of the power loss. The investigation revealed that the fuel filters inside the right-wing electric fuel pumps were darkened, dried, and adhered to the internal walls of the components, which restricted the flow of AvGas to the right engine. Additionally, corrosion was found within the pump housings, which prevented the bypass system from functioning correctly and providing an alternative fuel path.
The investigation also looked into maintenance practices. It was determined that maintenance interventions on these pumps did not comply with the aircraft's Maintenance Manual. Furthermore, the pilot's decision-making was analyzed, noting that while the aircraft's performance charts indicated that single-engine flight was possible at the aircraft's weight, the pilot opted for the emergency landing due to uncertainty regarding the engine failure.
Findings
- Improper maintenance of the electric fuel pumps, which failed to follow the manufacturer's manual regarding the cleaning or replacement of filter elements.
- Organizational failures in maintenance supervision, allowing corrosion and degraded filters to remain undetected.
- Inadequate emergency checklists, which did not include instructions for using cross-feed fuel supply in the event of an engine failure.
- Pilot experience levels, as the pilot's limited experience (approximately 20 hours) in the BN-2A-7 may have impacted his confidence to continue the flight in single-engine mode.