What happened
On June 28, 2015, a Sikorsky S-76C, registration PR-SEC, operated by Omni Taxi Aéreo S.A., was performing an offshore passenger transport flight to the maritime unit Kommander 3000 near Macaé, Brazil. After landing on the vessel's helideck, the crew began the process of disembarking and embarking passengers.
During this interval, the vessel's radio operator requested a change in the ship's heading from 351° to 096°. The pilot agreed to the maneuver. As the vessel executed the turn, it was struck by a wave that caused a significant pitch-up motion. This movement pushed the helicopter upward and to the right, causing the aircraft to slide across the helideck and damage the anti-slip netting. Fearing a rollover into the ship's main structure, the pilot initiated an emergency takeoff. During this maneuver, the aircraft tilted dangerously and passed very close to the vessel's superstructure, narrowly avoiding a collision. There were no injuries to the two crew members or four passengers, and the aircraft sustained no damage.
The investigation
CENIPA's investigation focused on the environmental conditions and the decision-making process during the vessel's maneuver. Investigators found that while the pilots were fully qualified and the aircraft was airworthy, the wind conditions had changed significantly due to the ship's turn. The wind, which was previously a side wind, became a crosswind of 29 knots, creating conditions prone to dynamic rolling.
Crucially, the investigation revealed that the vessel's Helideck Monitoring System (HMS) had indicated a "red light" status—signaling that motion parameters (such as pitch, roll, or heave) had exceeded safe limits—at 11:00 and 11:30 UTC, ten minutes before the helicopter landed. This critical safety information was not communicated to the flight crew. Additionally, investigators noted that the pilot did not adequately evaluate the risks associated with the vessel's heading change, specifically regarding the resulting wind shift and the ship's motion.
Findings
- The pilot's decision-making process regarding the vessel's maneuver contributed to the incident.
- The change in the vessel's heading altered the wind relative to the aircraft, creating a 29-knot crosswind that exacerbated the aircraft's lateral movement.
- The vessel's HMS had recorded unsafe motion parameters prior to landing, but this information was not provided to the crew.
- Environmental factors, specifically the impact of a wave during the maneuver, caused the initial displacement of the aircraft on the deck.