Investigation Summary
The accident occurred during a chartered flight transporting American tourists to San José for international connections. Punta Islita Airport is situated in a valley surrounded by rising terrain on three sides, with the only clear exit being to the south over the Pacific Ocean (Runway 21). Despite these geographical constraints, the crew opted for a northbound departure from Runway 3. Investigators noted that the crew likely chose Runway 3 to avoid exceeding the 10-knot tailwind limitation for Runway 21, as strong winds were reported in the area, though the airport lacked wind reporting equipment. A preceding Nature Air flight had successfully departed Runway 3 fifteen minutes earlier by making an immediate right turn through a mountain pass. In contrast, the accident crew continued on the runway heading into a blind valley. Surveillance footage showed the aircraft climbing toward mountains before entering a steep left turn. During this maneuver, the bank angle reached approximately 75 degrees, and the airspeed dropped below the published stall speed. The aircraft impacted a wooded slope in a near-vertical attitude and was destroyed by a post-crash fire. Investigators noted that while the captain was highly experienced, there was no documentation proving he had completed the operator's required initial operating environment training or airport-specific training for Punta Islita.
Final Conclusions
The NTSB concluded that the probable cause was the flight crew's failure to maintain airspeed while maneuvering to exit an area of rising terrain, resulting in an aerodynamic stall. Contributing factors included the decision to continue the takeoff toward terrain exceeding the airplane's climb capability, a lack of adequate weather reporting for wind determination at the airport, and the operator's lack of documented training for an airport requiring non-standard departures.
Photographic Evidence (1)
Video Analysis
Nature Air Flight 9916: The accident that shook Costa Rica — A detailed look at the 2017 Cessna 208B crash in Punta Islita, examining the challenging terrain and the crew's departure decisions.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Juan Manuel Retana, 52; cousin of former Costa Rican President Laura Chinchilla. Wikipedia reports 15,000 total hours.
First Officer
Emma Ramos, 26; had approximately 83 hours in multi-engine aircraft.
Systems & Failure Modes
Aerodynamic Stall
The aircraft exceeded its critical angle of attack during a steep turn, causing the wings to lose lift.
Pratt & Whitney PT6A-114A
Post-crash examination of the engine showed signatures consistent with the production of power at the time of impact.
Interesting Facts
- 01The aircraft was delayed 15 minutes at Punta Islita to inspect minor damage from a bird strike on the inbound leg.
- 02Punta Islita Airport lacked windsocks at the time of the accident, leaving the crew without visual wind data.
- 03The captain had over 11,000 hours of experience on the Cessna 208B, but his recent re-hire training records were incomplete.
- 04The aircraft impacted the terrain in a near-vertical attitude at an elevation of 238 feet MSL.
- 05Performance calculations indicated the aircraft could not have cleared the mountains to the north but could have cleared the pass to the east.
Safety Actions & Advisories
Operator Training Oversight
The investigation highlighted the need for documented airport-specific training for facilities with special characteristics or non-standard departure procedures.
Known Controversies & Unanswered Questions
Charter Flight Safety Regulation
Reference ↗Following the crash, U.S. media and the former head of the NTSB warned Americans against using privately chartered flights in Costa Rica, claiming they were not subject to proper safety oversight. These claims were strongly disputed by the Costa Rican National Chamber of Tourism and the Director of Civil Aviation, who called the reporting irresponsible.