HISTORY OF FLIGHT
On April 17, 2012, about 1155 central daylight time, a Sikorsky S-76B helicopter, N56RD, was substantially damaged during a forced landing in the Gulf of Mexico near the Joe Douglas oil drilling rig (Vermilion VR376A). The pilot, the airplane pilot-rated passenger in the copilot seat, and the five passengers seated in the cabin were not injured. The helicopter was registered to and operated by RDC Marine, Inc., under the provisions of 14 Code of Federal Regulations Part 91, as a business flight. Day visual meteorological conditions prevailed and no flight plan was filed. The flight departed at 1110 from Acadiana Regional Airport (ARA), New Iberia, Louisiana, and was destined for the Joe Douglas.
Background Information
The pilot reported that on Friday, April 13, 2012, he was flying the accident helicopter from an oil platform to Port Fourchon, Louisiana, when the helicopter had an apparent loss of power from the No. 2 engine during cruise flight. The pilot described the event as an engine rollback, but he was unsure about how much reduction in power the engine actually experienced. The autopilot was on when the loss of power occurred. The pilot noticed that the No. 1 torque needle was going into the One Engine Inoperative (OEI) range, so he disengaged the autopilot and lowered the collective to keep the engine out of the OEI range and prevent a temperature exceedance. He reported that there was no torque indicated on the No. 2 engine. He reported that the No. 2 engine was still operating because the N1 speed indicator (gas producer turbine) indicated that the engine was operating, but the pilot was unsure what the N1 needle read. He thought it might have been in the idle range, but he was not certain. The pilot switched back and forth on the load sharing switch between torque and T5 (engine temperature), but it did not seem to have any effect. The red engine out light and the blue manual reversion light did not illuminate. He reported that the No. 2 engine came back on line by itself. When it did, the No. 1 engine had a decrease in power, and the torque and temperature gauges matched up. He reported that the entire event lasted 10 to 20 seconds. After that, the No. 2 engine worked normally during the flight back to Port Fourchon.
Once at Port Fourchon, the pilot shut down the helicopter and checked for any electronic engine control (EEC) system fault codes that might have been recorded when the loss of engine power occurred. The pilot reported that there were no EEC fault codes recorded. He restarted the helicopter and performed hover and power checks. The helicopter appeared to be operating normally, so the pilot decided to continue with scheduled missions, which involved two more flights out to the oil rigs. The pilot overnighted in Patterson, Louisiana. The pilot telephoned the mechanic and left a message about the loss of power to the No. 2 engine. The mechanic was gone for the weekend and did not check his phone messages until Sunday night. The pilot flew three flights out to the oil rigs on Saturday before returning to Hobby Airport (HOU), Houston, Texas, where the helicopter was based. The pilot reported no anomalies occurred on Saturday.
The helicopter did not fly on Sunday. On Monday, the mechanic checked the EEC fault codes but there were none recorded. He checked the torque sensor cannon plugs and sprayed them with corrosion preventative. No engine runs or test flights were performed. No entries were made in the engine or airframe logbooks concerning the intermittent loss of power on April 13, 2012.
Accident Flight
On Tuesday, April 17, 2012, the pilot reported that he arrived at HOU about 0600 to prepare for the flight. The flight departed about 0700 with six passengers and full fuel en route to ARA, which took about one hour and forty minutes. The helicopter was refueled at ARA before departing for the Joe Douglas oil platform, which was located about 117 nautical miles away on a 180 heading. The helicopter arrived at the Joe Douglas platform about 45 minutes later.
The pilot reported that he made a visual approach on a 190 degree heading to the landing platform. He reported that the wind was from 220 degrees at 5 to 6 knots, according to the Garmin 500 GPS that was installed in the helicopter. He was flying directly towards the platform while decelerating from 60 to 45 knots while maintaining a 12 degree approach angle. The helicopter was about 60 feet from the landing pad and about 15 to 20 feet higher than the landing pad with a nose high attitude in the flare when a loss of engine power occurred. The pilot was unsure which engine had the loss of power. With the loss of power, the pilot reported that the trajectory of the helicopter would place it short of the landing pad. The pilot reported that the helicopter was going to hit the platform, so he pulled collective pitch, banked aft and to the left to avoid contact with the platform. Once clear of the platform, he attempted to lower the collective and gain airspeed, but the helicopter was in a high rate of descent with low airspeed. He pulled collective pitch and flared the helicopter before water impact. The pilot reported about 3 to 4 seconds transpired from the time he tried to avoid hitting the platform to when the helicopter impacted the water. After impacting the water, the helicopter remained on top of the surface as the pilot kept engine power on the helicopter to keep it from sinking. He deployed the emergency floatation bags and attempted to water taxi toward the oil platform, but there was no directional control since the tailboom was partially separated from the fuselage.
The pilot continued to keep engine power on the helicopter as a rescue pod from the Joe Douglas was lowered to the water. The passengers in the cabin were preparing to deploy the life rafts as the rescue pod was being launched. When the rescue pod was near the helicopter, the pilot shut down the engines. The passengers deployed the life rafts as the helicopter began to list to the left. All six passengers and the pilot got into the rafts, and then transferred into the rescue pod, which was then winched back up to the deck of the platform. None of the occupants reported any injuries.
Sometime after the occupants egressed, the helicopter inverted in the water with the four floatation bags keeping it from sinking. However, the bags were compromised during the initial recovery effort and the helicopter later sank in about 310 feet of water. The helicopter was recovered on April 25, 2012, and taken to Port Fourchon where it was examined on April 27, 2012.
PERSONNEL INFORMATION
The pilot held an airline transport certificate with helicopter and single-engine land ratings. He held helicopter and airplane instrument ratings, and was a flight instructor with helicopter, airplane single-engine, airplane multi-engine, instrument helicopter, and instrument airplane ratings. He held a first class medical certificate that was issued on April 16, 2012, with a limitation for corrective lenses. The pilot reported that he had a total flight time of 16,000 hours with 677 hours in Sikorsky S-76B helicopters. He had 36 years of flying experience, with 23 years as a pilot for the operator.
The airplane pilot-rated passenger held an airline transport certificate and was an airplane pilot for the operator. He reported he had about 13,000 hours of total flight hours. He had no formal training in helicopters, but he had about 25 hours of "left seat" time in helicopters. He had flown once before with the accident pilot.