What happened
On September 15, 2014, at approximately 2:00 p.m., a RANS S12 ultralight aircraft, registration EC-YJD, was conducting a local recreational flight test near San Rafael del Yuma, La Altagracia. The pilot was performing a weight and balance test to determine the aircraft's capacity to carry a passenger by using two bags of cement as simulated weight in the right seat.
After taking off from a flat field adjacent to a hangar, the aircraft reached an altitude of approximately 200 feet. During the flight, the pilot executed an uncoordinated right turn. This maneuver, combined with the asymmetrical weight distribution, caused the aircraft to enter a stall. The aircraft subsequently plummeted into bushes located along the roadside between San Rafael del Yuma and Boca de Yuma. The pilot sustained serious injuries, including multiple fractures to the right humerus and a concussion, while the aircraft suffered major structural damage.
The investigation
The CIAA investigation examined the aircraft's mechanical condition, the pilot's experience, and the environmental factors. Investigators found that the aircraft's flight controls were fully operational and no prior structural fatigue or corrosion was detected. The weather conditions at the time of the accident were optimal, with good visibility and light winds.
However, the investigation noted a regulatory discrepancy regarding the aircraft's fuel capacity. The aircraft was equipped with a removable tank containing approximately 19 gallons, which, when combined with the main wing tanks, exceeded the fuel capacity limits established for ultralight operations under RAD 103. Additionally, investigators noted that the aircraft wreckage was removed from the hangar before CIAA personnel could authorize the removal.
Findings
- The primary cause of the accident was a lack of sufficient knowledge regarding weight and balance by the pilot.
- The use of cement bags in the right seat created an unbalanced load that contributed to the loss of lift during an uncoordinated turn.
- The aircraft's fuel capacity exceeded the legal limits for an ultralight classification under local regulations.