WEEK 24
H2F brings you the ‘helicopter mayday of the week’ with a short accident report summary. I tell you what happened. You think more about why it happened. We all learn from it. Because that’s what accident reporting is for.
TITLE
Rotor strike with offshore platform during night training approach.
WHAT?
An AW139 was conducting offshore landing training on a semi-submersible drilling rig when the helicopter’s main rotor struck structures adjacent to the helideck during the final stage of the first approach. The helicopter sustained substantial damage and came to rest on the helideck.
WHERE?
Ocean Courage semi-submersible drilling rig, offshore Brazil.
WHEN?
2 June 2021 during an offshore night training mission.
HOW?
The crew was conducting recurrent offshore night training involving multiple approaches and landings to the platform’s helideck. During the approach, the helicopter remained stable until the final stage. On reaching the confined helideck environment, the main rotor struck structures adjacent to the landing area. It remained on the deck but sustained extensive rotor system and airframe damage.
CONDITIONS?
The flight was conducted at night to an offshore helideck. The operation was for training rather than a revenue flight, increasing the importance of instructor supervision and clearly defined crew responsibilities. The proximity of platform structures to the helideck provided little margin for error. Although the investigation found weather conditions were suitable for flight and did not identify wind or aircraft performance as causal factors, the combination of darkness, artificial platform lighting and the complex obstacle environment significantly increased visual workload during the final approach.
OUTCOME?
The AW139 sustained substantial damage. The pilot in command received minor injuries, the second-in-command and a helideck technician were seriously injured, and the single passenger escaped injury. There was no post-impact fire.
WHY?
Investigators concluded that the helicopter collided with platform structures because the crew lost the required obstacle clearance during the final stages of the approach. The investigation identified several interacting operational and human factors:
Situational awareness progressively deteriorated as both crew’s attention became focused on the landing task, reducing effective monitoring of the rotor clearance from nearby platform structures.
CRM broke down during the critical phase of flight. Monitoring & communication became less effective, reducing the crew’s ability to detect the developing hazard before rotor impact.
The instructor-supervision dynamic was ineffective. Although this was a training flight, the supervising captain did not intervene early enough to prevent the approach from continuing into an unsafe condition, with a delayed transition from instruction to command authority.
Workload associated with a night offshore approach reduced the crew’s capacity to maintain an effective scan of aircraft attitude, obstacle clearance and landing references simultaneously in the confined helideck environment which required precise aircraft positioning while maintaining awareness of surrounding steel structures.
No mechanical malfunction contributed to the accident.
REFERENCE?
Centro de Investigação e Prevenção de Acidentes Aeronáuticos. (2025). Final Report A-078/CENIPA/2021: Leonardo Helicopters AW139, PR-OTF, 2 June 2021. Brazilian Aeronautical Accident Investigation and Prevention Center (CENIPA).
Note:
Accident reports selected from the following open source databases: US NTSB; UK AAIB; Flight Safety Foundation’s Aviation Safety Network; Australia’s ATSB. Ireland’s AAIU; Taiwan’s TTSB; France’s BEA; Spain’s CIAIAC. Germany’s BFU.
competentaviators.com 