What happened
On February 7, 2012, a Sikorsky S-76C, registration PR-CHO, operated by BHS Brazilian Helicopter Services Taxi-Aéreo S.A., was performing a passenger transport flight from Macaé, Rio de Janeiro, to the helideck of the vessel Lochnagar. The flight involved two crew members and eight passengers.
During the approach to the helideck, located at the bow of the ship, the crew executed a parallel approach, keeping the vessel's superstructure to the right of the aircraft. As the pilot attempted to transition laterally to position the aircraft over the touchdown area, the tail rotor struck a white guardrail belonging to a ladder access point on the port side of the ship. The impact caused a noticeable vibration and a tendency for the nose to yaw to the right, prompting the crew to perform an immediate landing. The aircraft sustained light damage, and all 10 people on board escaped without injury.
The investigation
The CENIPA investigation examined the flight path, the crew's qualifications, and the regulatory environment governing maritime helidecks. Investigators found that while the pilots were fully qualified and experienced in the route, the aircraft's approach trajectory was flawed. The crew failed to complete the necessary longitudinal movement before initiating the lateral shift, which placed the tail rotor within the Limited Obstacle Sector (SOAL).
Furthermore, the investigation scrutinized the maritime regulations (NORMAM 27) in effect at the time. It was noted that the regulations lacked clear instructions regarding the precise positioning of the aircraft within the touchdown area. The investigation also identified that the white guardrail was difficult to perceive due to its color and lack of high-visibility markings. Additionally, the helideck lacked the "D-value" markings required by regulation, which are intended to help crews verify the safety margin for the aircraft's dimensions.
Findings
- The crew initiated lateral movement before sufficient longitudinal clearance from obstacles was achieved.
- Inadequate regulatory clarity in NORMAM 27 regarding the correct positioning of the aircraft within the touchdown area.
- The shipboard obstacle (guardrail) lacked high-visibility markings, making it difficult for the crew to identify the hazard.
- The helideck lacked required visual references, such as the "D-value" marking, to assist in determining safe clearance.
- Deficiencies in cockpit resource management contributed to the error in the approach profile.