What happened
On July 5, 2003, at approximately 13:34, a Sikorsky SK-76A helicopter, registration PT-YVM, operated by BHS Helicópteros, was performing a passenger transfer flight near Macaé, Rio de Janeiro. The aircraft departed from the São Tomé helipad to approach the vessel *Toisa Mariner* to disembark three passengers.
During the final approach to the ship's helipad, the helicopter's tail rotor collided with the vessel's main mast. The impact caused an immediate loss of directional control, resulting in a rapid rightward rotation. The aircraft subsequently struck the sea and sank quickly to a depth of approximately 820 meters. There were five fatalities in total, including the two crew members and the three passengers on board. The aircraft was destroyed.
The investigation
CENIPA investigators examined the aircraft's maintenance records, flight crew qualifications, and the operational environment of the offshore landing. The investigation confirmed that the aircraft was well-maintained, with all inspections up to date, and the crew was fully qualified and experienced for the mission. Meteorological conditions were favorable, with CAVOK visibility and moderate winds.
The investigation focused on the approach path chosen by the crew. While the helipad on the *Toisa Mariner* was an approved landing site, it featured a significant obstacle: a mast located approximately 14.5 meters from the center of the helipad. Witnesses on the ship noted that the crew chose an approach sector that was not typically used by other pilots because it placed the aircraft directly over the obstacle zone. Analysis of the Cockpit Voice Recorder (CVR) showed that the flight proceeded normally until the moment of impact, with no recorded discussion regarding the specific risks of the chosen approach path.
Findings
- The primary cause of the accident was the decision to execute an approach through a sector containing obstacles, specifically the ship's main mast.
- The crew failed to utilize available and safer approach sectors that would have avoided the mast.
- A lack of effective cockpit coordination was noted, as the crew did not communicate or assign specific tasks to manage the risks associated with the difficult approach.
- The investigation identified a psychological factor involving "local adaptations," where routine successful operations in challenging environments may lead crews to deviate from standard procedures and underestimate latent risks.
- The ship's positioning relative to the wind made the approach difficult, though not impossible, to perform safely.