What happened
On May 22, 2018, a Cessna 208B Grand Caravan, registration PT-FLW, operated by Amazonaves Táxi Aéreo Ltd., was performing a shuttle flight from Eduardo Gomes International Aerodrome to Flores Aerodrome in Manaus, Brazil. While executing visual traffic for landing at Flores Aerodrome, the aircraft experienced a sudden loss of engine power and abnormal engine behavior.
In response to the power loss, the pilot attempted an emergency landing in an unprepared area located approximately 300 meters from the threshold of runway 11. Following the impact, the aircraft caught fire and was completely destroyed. The pilot sustained minor injuries.
The investigation
CENIPA's investigation focused on the engine's performance and the pilot's emergency response. The aircraft was equipped with a Pratt & Whitney Canada PT6A-114A engine, which was operating under an authorized extension of the Time Between Overhaul (TBO) interval. Investigators found that the engine's hot section had sustained damage, specifically melting in the compressor turbine blades, indicating that Interstage Turbine Temperature (ITT) limits had been exceeded.
Because the fire completely consumed the Fuel Control Unit (FCU), a detailed analysis of the unit's internal components was impossible. The investigation also examined the pilot's decision to retract the flaps following the engine failure. While the checklist prescribes flap retraction during engine failure, the investigation noted that the aircraft was at a low altitude during the approach, and the loss of lift from retraction may have prevented the aircraft from reaching the runway using the engine's residual power.
Findings
- Engine Over-temperature: Evidence of melted turbine blades suggests an extrapolation of ITT limits, potentially caused by the use of the Emergency Power Lever (EPL).
- Pilot Decision-making: The retraction of the flaps may have caused a loss of lift and a sinking rate that prevented the aircraft from reaching the intended runway.
- Training and Memory: The investigation identified potential deficiencies in the frequency or quality of emergency training, noting that the pilot may have struggled to recall critical memory items during the high-stress event.
- Engine Status: The engine was operating under a valid TBO extension, and no evidence was found to suggest the extension itself contributed to the failure.