History of Flight
On October 9, 2013, about 0720 central daylight time, a Bell 206L-3 helicopter, registration N54LP, was substantially damaged when it impacted water shortly after takeoff from the Main Pass (MP) 107D oil platform in the Gulf of Mexico. The commercial pilot was fatally injured and the three passengers were seriously injured. The helicopter was registered to and operated by Panther Helicopters, Inc., Belle Chasse, Louisiana. Visual meteorological conditions prevailed and a company visual flight rules flight plan was filed for the business flight, which was destined for the Belle Chasse Heliport (06LA), Belle Chasse, Louisiana. The flight was conducted under 14 Code of Federal Regulations Part 135.
The flight was a routine crew change. The pilot and three passengers departed 06LA about 0633 and flew direct to MP107D. After landing, the pilot did not shut down the helicopter and remained at the controls with the main rotor turning until the crew change was complete. A witness on a nearby platform observed the helicopter lift into a hover, move forward, and then saw a flash and a cloud of white smoke under the main rotor blades, followed by a loud screeching noise. The helicopter nosed over toward the water, its emergency floats deployed, and it struck the water hard, becoming submerged and rolling inverted. The witness directed a boat to the scene, and three occupants were rescued.
Passengers reported hearing abnormal noises before impact. One passenger stated the pilot declared a mayday and deployed the floats. Another passenger noted the helicopter rolled onto its left side after water entry.
Personnel Information
The pilot held a commercial pilot certificate for rotorcraft-helicopter and a private pilot certificate with airplane single-engine land rating. His last FAA second-class medical was issued on January 10, 2013. According to the operator, the pilot had accrued 3,450 total hours, including 3,423 hours in helicopters and 177 hours in the same make/model as the accident helicopter. He was hired by Panther on June 17, 2013, and completed his Part 135 check-ride on July 25, 2013.
Aircraft Information
The accident helicopter was a 1991 Bell 206L-3, serial number 51466. It was powered by an Allison M250-C30P turbo-shaft engine, serial number CAE 895524, driving a two-bladed main rotor and a two-bladed tail rotor. The engine had 10,670.8 hours at the time of the accident. The helicopter was configured to carry one pilot and six passengers. Its last inspection was completed on October 3, 2013, and total time was 11,238 hours.
Meteorological Information
At 0600, weather at Belle Chasse Heliport (about 72 nautical miles northwest) was calm wind, visibility 10 miles, clear skies, temperature 65°F. At 0655, weather at New Orleans Naval Air Station (72 miles northwest) was calm wind, visibility 10 statute miles with shallow fog, few clouds at 5,000 feet, temperature 57°F, dew point 60°F, altimeter 30.06 inHg.
Helipad Information
The MP 107 D facility is a fixed, five-slot, manned platform in 61 feet of water, about 17 miles off the Louisiana coast. It was operated by Energy XXI GOM, LLC at the time of the accident. The helideck was 35 feet by 35 feet.
Wreckage and Impact Information
The wreckage was recovered and examined. The engine, transmission, and main rotor remained attached. One main rotor blade was cut for transport; the other fractured during impact. The tail boom separated about 12 inches aft of the attachment point. Flight control continuity was confirmed for cyclic and collective; partial continuity for anti-torque pedals. The throttle was in the fuel-cutoff position. Examination of seatbelt assemblies found the pilot's inertial reel locked with stretch marks; the front passenger's inertial reel was not locked. The engine was shipped to Rolls Royce for tear-down examination. Metallurgical testing of the second stage turbine blade revealed high cycle fatigue (HCF) from the trailing edge area, with no material anomalies. The blade failed in HCF, which subsequently damaged third and fourth stage blades. Rolls Royce conducted an updated dynamics analysis and found no mode crossing within normal operating range that would be consistent with HCF initiation at the observed location. Three other potential scenarios were evaluated: normal operation resulting in tip rub, distorted blade geometry from foreign object debris (FOD), and abnormal operation (NG over-speed, compressor stall, distortion). No FOD-related damage was identified. Abnormal operation could not be ruled out, but there were no reports of excessive vibration, compressor stall, or surges before the accident.
Additional Information
MP107D was an active oil production platform. Methane, a by-product, is vented via a flare boom extending from the platform. A witness reported seeing a methane cloud from the boom the day before the accident but did not see venting on the morning of the accident. Passengers reported no methane venting at the time of the accident.