What happened
On September 16, 2019, an ATR-72 202, registration PR-MPY, was performing a regular public air transport flight from Itaituba to Manaus. The flight was diverted back to Itaituba after an incident involving another aircraft rendered the destination airport in Manaus inoperative.
While the aircraft was on approach to Itait anduba, the left-hand engine shut down at an altitude of approximately 1,446 ft AGL. Following the landing, the right-hand engine also ceased operation while the aircraft was taxiing. Upon reaching the parking area, the crew discovered that there was no usable fuel remaining in the wing tanks. There were no injuries to the four crew members or the 39 passengers, and the aircraft sustained no damage.
The investigation
CENIPA's investigation focused on the fuel indication system and the circumstances leading to the fuel exhaustion. The investigation revealed that the Fuel Quantity Indicator (FQI) system was providing inaccurate data. Specifically, several fuel probes in both wings were operating outside of prescribed parameters, and the low fuel-level indicator for the left-hand tank was inoperative.
Technical inspections following the incident led to the replacement of several fuel probes and a wiring harness. The investigation also examined the operational environment, noting that the lack of ground support staff at the Itaituba aerodrome increased the pilots' workload during post-flight and refueling tasks. Furthermore, the investigation looked into the maintenance oversight of the operator, as the aircraft's maintenance was performed by a third-party company.
Findings
- Inaccurate fuel indication: Multiple fuel probes and electrical harnesses were found to be non-compliant with prescribed parameters, directly interfering with the accuracy of the fuel quantity readings.
- Crew Resource Management: There was an inefficient management of tasks between the pilots, which contributed to the failure to observe the minimum fuel requirements for the operation.
- Maintenance oversight: There were failures in the monitoring and oversight of the maintenance services provided to the operator.
- Increased workload: The absence of support personnel at the aerodrome for refueling and pre-flight tasks likely contributed to pilot distraction.
- Maintenance non-conformity: The investigation identified non-conformities in previous maintenance services that allowed the fuel system errors to persist.