CEN23FA071

The pilot’s failure to ensure the helicopter was clear of obstacles before takeoff from the helideck, which resulted in the helicopter’s right landing skid pivoting about a helideck perimeter light during takeoff and a dynamic rollover. Additionally, the pilot’s improper takeoff technique likely contributed to the development of dynamic rollover.

The on-demand passenger flight was departing from an offshore production platform when, upon liftoff, the helicopter entered an abrupt right roll and crashed into the helideck and then descended into the water. Recorded parametric data indicated that shortly after liftoff, about 2 ft above the helideck, the helicopter was in a 32° right roll with a right roll rate of about 68 degrees per second when the device stopped recording. A review of the helicopter’s in-cockpit video camera revealed that the pilot did not land the helicopter in the center of the helideck during the landing that preceded the accident takeoff. Additionally, the pilot did not reposition the helicopter before the accident takeoff. Based on video evidence, the position of the helicopter on the helideck resulted in the aft portion of the right skid to be adjacent to a helideck perimeter light. Examination of the helideck revealed impact gouges in the helideck surface that matched the bolt head pattern of the helicopter’s right skid tube. These gouges likely were created when the helicopter was in a steep right bank angle. The location of the impact gouges in the helideck surface further supports that the aft portion of the right skid tube was in contact with the helideck perimeter light at takeoff. The perimeter light housing, whose attachment hardware to the helideck was not frangible, was found significantly deformed. Based on the physical and video evidence, the helideck perimeter light became the pivot point for a dynamic rollover to occur during takeoff. The helideck perimeter lights were 2 inches higher than the construction standard of 6 inches. However, because the helicopter’s right skid was already in contact with the perimeter light before the takeoff, the out-of-compliance height of the perimeter light, by itself, did not contribute to dynamic rollover. Examination of the helicopter wreckage found no evidence of preimpact failure of the airframe, the main and tail rotor systems, or the engine. The main rotor blades and hub exhibited signatures of powered impact damage consistent with engine power delivery to the rotor system when the blades impacted the helideck. Additionally, the recovered engine control unit data confirmed that the engine was functioning normally up until the main rotor blades impacted the helideck. Examination of the flight control system found no evidence of preimpact fractures, disconnections, or restrictions. The lateral hydraulic servo actuator, which controls the helicopter in the roll axis, exhibited normal functionality during bench testing. A review of the pilot’s previous takeoffs revealed that he typically did not follow company policy to bring the helicopter into a 3-5 ft hover check before continuing with the takeoff. The pilot’s improper takeoff technique (without a brief 3-5 ft hover check) would have decreased his ability to identify and react to any anomalies during the takeoff, including the onset of a dynamic rollover. All three requirements for a dynamic rollover (thrust exceeding helicopter weight, a pivot point other than the helicopter’s center of gravity, and a rolling moment) were present during the accident takeoff. Based on the video evidence, the pilot was likely unaware the helicopter’s right skid was in contact with the helideck perimeter light before takeoff. Toxicological testing of pilot’s samples detected low levels of ethanol in blood and vitreous fluid, high ethanol levels in liver tissue, but no ethanol in urine. This ethanol pattern is not consistent with consumption and is likely from postmortem production, as the levels vary significantly amongst specimens and there was no ethanol detected in the urine. Therefore, the detected ethanol did not contribute to the accident.

The pilot was hired by RLC on September 12, 2022. When he submitted his resume for employment, the pilot reported a total flight experience of 1,512 hours in helicopters, of which 1,188 hours were flown as PIC. He previously worked for five helicopter operators, and had flight experience in Robinson, Guimbal, Bell, and Sikorsky helicopters. On September 28, 2022, the pilot completed his RLC initial ground training and initial flight training, and then was subsequently assigned as a VFR pilot-in-command (PIC) in the Bell 407 helicopter. The training included the pilot’s initial pilot testing (per Title 14 CFR Part 135.293) , PIC instrument proficiency check (Part 135.297), and PIC line check (Part 135.299). Flight grade slips dated September 13, 18, 19, 20, and 23, 2022, evaluated the pilot as satisfactory in the task “Dynamic Rollover (Oral).” Additional grade slips dated September 19, 20, 24, and 27, 2022, evaluated the pilot as satisfactory in “Pinnacles or Platform.” The pilot’s total flight experience in helicopters, including the 155.8 flight hours flown while employed by RLC, was 1,667.8 hours, of which 1,343.8 hours were flown as PIC. A review of RLC flight records revealed that the pilot had operated to and from WD-106 a total of 23 times. According to the RLC Director of Training, after considering the weights of the pilot and passengers, their seating arrangements in the helicopter, the weight of their personal baggage, and the estimated fuel quantity remaining at the time of the accident, the helicopter was loaded in accordance with the General Operations Manual (GOM). The autopsy of the pilot was performed by the Jefferson Parish Forensic Center, as authorized by the Lafourche Parish Coroner. According to the autopsy report, the cause of death was multiple blunt force injuries with subsequent drowning. The manner of death was accident. According to the autopsy report, extensive head and facial trauma was present. The autopsy did not identify significant natural disease. At the request of the Jefferson Parish Coroner’s Office, NMS Labs performed toxicology testing of the pilot’s postmortem liver tissue. Ethanol was detected at 0.11 g/dL. Caffeine was also presumptively positive in liver tissue. The FAA Forensic Sciences Laboratory completed postmortem toxicological testing of specimens obtained during the pilot autopsy. Ethanol was detected in cavity blood at 0.042 g/dL and vitreous fluid at 0.029 g/dL but was not detected in urine. Isopropanol was detected in cavity blood at 0.004 g/dL but not in vitreous fluid or urine. N-propanol was detected in cavity blood and vitreous fluid but not urine. N-butanol was detected in cavity blood but not vitreous fluid or urine. The cavity blood specimen was unsuitable for carboxyhemoglobin testing. Ethanol is a type of alcohol. It is the intoxicating alcohol in beer, wine, and liquor, and, if consumed, can impair judgment, psychomotor performance, cognition, and vigilance. FAA regulation imposes strict limits on flying after consuming ethanol, including prohibiting pilots from flying with a blood ethanol level of 0.04 g/dL or greater. Alcohol consumption is not the only possible source of ethanol in postmortem specimens. Ethanol can sometimes be produced by microbes in a person’s body after death. Postmortem ethanol production is made more likely by extensive traumatic injury and can cause an affected toxicological specimen to test positive for ethanol while another specimen from the same person tests negative. Isopropanol is an alcohol commonly found in in disinfectants, anti-freeze, and window cleaners. Isopropanol can also be found in postmortem specimens due antemortem or postmortem sources. Postmortem production of isopropanol is a byproduct of the decomposition process due to microbial activity. N-propanol and particularly n-butanol are other alcohols that can be produced by microbes in a person’s body after death. Their presence in a postmortem specimen is potentially indicative of postmortem microbial activity in the specimen but does not reliably indicate that postmortem ethanol production occurred. Caffeine is a central nervous system stimulant that is commonly ingested, including in coffee, tea, soft drinks, and chocolate, and is also an ingredient in certain anti drowsiness medications and headache medications. Caffeine is not generally considered impairing. Examination of the WD-106 production platform after the accident revealed composite debris scattered throughout the multiple levels of the platform. The scattered debris was consistent with the internal materials used in helicopter main rotor blades. A majority of one main rotor blade, identified as serial number A-1532, was located on the cellar deck, two levels below the helideck, resting against a metal handrail. The handrail exhibited a downward bend near the location the blade. Three pieces of lead weight, consistent with blade weights, were also found on the cellar deck near the blade. Multiple pieces of dark tinted acrylic, consistent with the cabin roof windows of the helicopter were found in the same location. The acrylic shards exhibited red color transfer consistent with the red paint of the stairwell. The helicopter’s upper hydraulic servo cover, normally located above the cockpit, also exhibited the same red color transfer. Sections of the tail rotor were found on the main deck below the helideck. No specific object on the platform could be conclusively identified as the contact point with the tail rotor. Further examination of the helideck revealed that the center blue light assembly on the northwest elevation of the helideck was damaged but still attached to its 6 inch by 6 inch light mount. Although the light remained installed on the mount, its blue glass globe was fragmented and the metal protective guard for the globe was significantly deformed and bent toward the stairwell, as shown in Figure 2. After the accident, a platform employee removed the damaged light assembly from the mount out of concern for safety during future use of the helideck. The amber light, located on the west corner of the helideck, near the stairwell, separated from its mount and was not recovered. The remaining perimeter lights appeared undamaged. The red paint around the stairwell exhibited scratches and gouges. The safety skirting that bordered the stairwell (northwest and southwest sides) was damaged. There were multiple impact marks on the metal frame of the helideck around and below the area of the damaged safety skirting and stairwell. Two areas of gouges in the paint on the helideck were present. The first area was a row of nine irregularly spaced but inline gouges, as depicted in Figure 3, located inside the aiming circle and adjacent to the “W” icon logo painted on the helideck. The second area was a group of five irregularly spaced gouges, found in the black paint of the aiming circle, near the northeast side and near the damaged center light. Figure 4 is an illustration showing the location of the two areas of paint gouges and the damaged light assembly. Figure 2. Photo (left) of the damaged center perimeter light shortly after the accident (Source: Walter Oil and Gas). Photo (right) of the same light assembly after it was removed from the helideck (Source: NTSB). Figure 3. Image identifying some of the damage to the helideck. Figure 4. Illustration depicting the location of the two groups of gouges in the helideck paint and the location of the damaged perimeter light assembly. During a subsequent examination, an exemplar Bell 407 helicopter was used to determine the before-takeoff position of the accident helicopter on the WD-106 helideck. The exemplar helicopter’s Appareo video recorder field of view (FOV) was calibrated to match the accident helicopter’s Appareo FOV. The exemplar helicopter was flown to WD-106 and parked in