What happened
On November 1, 2014, at approximately 11:05 a.m., a Bell 206B helicopter, registration HI-419, crashed into a sugarcane plantation near Cayacoa, San Pedro de María, Dominican Republic. The aircraft, operated by Servicios Aéreos Profesionales, was conducting a private flight for aerial photography and observation of a local cement factory.
The flight crew was performing a descent from 800 feet to 500 feet when the pilot experienced intense vibrations and a sudden loss of engine power. The pilot notified the Las Américas International Airport tower of his intention to land due to these vibrations, but communication was lost shortly thereafter. The pilot attempted to execute an autorotation, but the vibrations became uncontrollable, leading to a high-energy impact with the terrain. The crash resulted in one fatality and two serious injuries.
The investigation
The CIAA investigation focused on the mechanical state of the aircraft and the sequence of events leading to the power loss. Investigators examined the engine, which remained running for an indeterminate period after the impact, and found no internal defects or malfunctions in the turbine or the starter generator. The engine was subsequently sent to the manufacturer in the United States for testing, which confirmed its ability to produce normal power.
However, the investigation identified significant structural issues within the airframe. While the engine and main transmission components were intact, the mechanical floor supporting the engine and the main transmission showed advanced stages of corrosion. The investigation also noted that the search and rescue response was delayed, as the crash site was difficult to locate, and the responding helicopter lacked medical personnel or first aid training.
Findings
- The primary contributing factor was the advanced corrosion on the mechanical floor of the engine and main transmission.
- During the descent from 800 to 500 feet, the structural stress caused the corroded floor to collapse.
- This collapse led to the disconnection of the short shaft, resulting in a sudden loss of power and severe vibrations.
- The loss of power forced the pilot into an autorotation maneuver that could not be stabilized, leading to the crash.
- The delay in medical assistance and the lack of specialized medical equipment in the initial search helicopter contributed to the death of the passenger.