Accident Overview
On December 15, 2022, about 0815 central standard time, a Bell 206-L4 helicopter, registration N414RL, was substantially damaged when it rolled off a helideck at the Ship Shoal 105C offshore oil platform in the Gulf of Mexico. The helicopter was operating under 14 Code of Federal Regulations Part 135 as an on-demand air taxi flight. The pilot and two passengers sustained minor injuries and were rescued after egressing into the water.
Flight History
According to the pilot, during the approach to the platform, he observed wind gusting from the north. He turned the helicopter's nose to the northeast to position the disembarking passengers near the stairway. During the subsequent takeoff, the front skids lifted off the helideck, and the north wind pushed against the helicopter. The skids became stuck, causing the aft right skid to contact a light. The helicopter then rolled over. The pilot was unable to regain control, and the helicopter rolled off the helideck. During the uncontrolled descent, the pilot activated the emergency floats before impacting the water.
Pilot and Operator Statements
The pilot stated that he had recently been trained on a non-standard takeoff technique in a Bell 407, which involved raising the front skids first by applying aft cyclic before lifting to a hover. He used this technique during the accident takeoff. He noted that the helicopter's stinger (tail skid) might have been lower than normal and may have contacted helideck lights or safety skirting, initiating the roll. The operator's chief pilot summarized that the pilot made an approach from the south, terminated to a hover, and rotated the nose right 45° to align the stairs. During lift-off, the wind came from the left side, and the helicopter contacted the helideck on the aft right side, possibly contacting lights, resulting in a dynamic rollover. Both the pilot and chief pilot reported no mechanical malfunctions with the helicopter.
Investigation Findings
Postaccident examination by an FAA inspector revealed witness marks and damage on the aft right skids of the helicopter. No preaccident mechanical malfunctions or failures were found that would have precluded normal operation. Photos of the helideck showed a blue light and metal safety skirting damaged and partially separated on the bottom right side near the stairway. The NTSB Vehicle Recorder Division attempted to extract data from an Appareo Vision 1000 recorder installed in the helicopter, but the device exhibited moisture and corrosion, preventing recovery of usable information.
Operational Procedures
The operator's General Operations Manual (GOM) for platform takeoffs includes standard procedures such as beginning from a stabilized hover, taking off into the wind, and using forward cyclic to transition to forward flight. Special considerations caution against non-normal takeoff techniques unless required for obstacle clearance. The pilot's use of a different technique deviated from the standard procedures.
Technical Information
The FAA Helicopter Flying Handbook describes dynamic rollover as a lateral rolling tendency when a helicopter is in contact with the surface. It can occur if a skid contacts a fixed object, or if improper technique is used. Once the critical rollover angle is exceeded, recovery is impossible with cyclic control alone, and collective pitch must be reduced. This concept was referenced in the investigation.