What happened
On December 31, 2017, a Cessna 208B Caravan, operating under Costa Rican registration TI-BEI, crashed into terrain near Corozalito, Costa Rica. The aircraft was performing a commercial charter flight for Nature Air, transporting 10 passengers and 2 crewmembers from Islita Airport (MRIA) to Juan Santamaría International Airport (MROC).
The accident occurred approximately 15 minutes after a preceding aircraft of the same type had departed from the same runway. While the first aircraft performed a right turn through a mountain pass to clear the terrain, the TI-BEI continued on the runway heading into a valley with rising terrain. Surveillance video captured the aircraft climbing on the runway heading before initiating a left turn. During this maneuver, the bank angle increased to approximately 75 degrees, and the aircraft descended into the terrain about 0'4 statute miles from the end of runway 3.
The impact was followed by an explosion and fire, which destroyed the aircraft. All 12 people on board were fatally injured.
The investigation
Investigators examined the wreckage, which was severely fragmented and burned. The engine showed evidence of producing power at the time of impact, with the compressor blades and vanes showing signs of rotation. Although the aircraft had sustained a bird strike to the left wing leading edge prior to the flight, investigators determined the damage was localized and would not have adversely affected flight controllability.
Performance calculations were conducted for three departure scenarios:
- A right turn following the path of the previous aircraft, which would have provided sufficient climb margin.
- A straight-out departure on the runway heading, which showed a negative climb margin of -14% at maximum allowable weight.
- A left turn following the valley floor, which also showed a negative climb margin of -8% at maximum allowable weight.
Regarding the crew, the captain was highly experienced with over 11,000 hours in the Cessna 208B, though documentation regarding the completion of required flight training and check flights under the operator's manual was limited. The first officer had approximately 453 hours of total flight experience.
Findings
- The flight crew failed to maintain adequate airspeed during a maneuver to exit rising terrain, leading to an aerodynamic stall.
- The crew chose a departure path toward rising terrain that likely exceeded the aircraft's climb capability.
- There was a lack of adequate weather reporting at the airport to assist in determining wind direction and intensity.
- There was a lack of documented training for an airport requiring a non-standard departure procedure.