Interesting because of the prior lightning strike.
NTSB Identification: DFW07IA184
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Incident occurred Thursday, August 16, 2007 in Gulf of Mexico, GM
Aircraft: Bell 407, registration: N433PH
Injuries: 1 Minor, 1 Uninjured.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.
On August 16, 2007, at 1513 central daylight time, a single-engine Bell 407 helicopter, N433PH, was undamaged during an emergency landing to the water in the Gulf of Mexico. The commercial pilot sustained minor injuries and the passenger was not injured. The helicopter was registered to and operated by Petroleum Helicopters Incorporated, of Lafayette, Louisiana. A company visual flight rules flight plan was filed for the on-demand air taxi flight that departed the East Cameron 109 (EC109) offshore platform at about 1507, and was destined for the West Cameron 98 (WC98) offshore platform. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 135 flight.
In a written statement, the pilot reported that he departed the EC 109 platform and climbed to an altitude of approximately 1,000 feet and filed his flight plan with the operator's communications center. Approximately five minutes after departure, the engine chip light illuminated and the pilot immediately turned back to the departure platform. While in the turn, the pilot reported hearing a "high pitched grinding noise" and a "pop" before the engine stopped producing power.
The pilot entered an autorotation to the ocean as he made a Mayday call to his company's communications center. Approximately 75 to 100 feet above the water, the pilot initiated a flare to slow the helicopter's descent and attempted to deploy the emergency floats; however, he did not pull the handle hard enough. The pilot made a second attempt, which was successful, and the floats deployed when the helicopter was approximately 10-feet above the water. The pilot "pulled pitch" and the helicopter landed safely on the water with the floats fully inflated. Shortly thereafter, a large wave impacted the helicopter and broke out the right windshield and rolled the helicopter inverted.
The pilot and the passenger were able to exit the helicopter and deploy one of the on-board life rafts. Once both individuals were in the life raft, the pilot activated the EPIRB and another PHI helicopter was able to direct a nearby shrimp boat to the life raft. The pilot and the passenger were taken onto the boat and were later recovered by a United States Coast Guard helicopter.
The operator recovered the helicopter the following day and transported the helicopter to their maintenance facility in Louisiana, where representatives from the Federal Aviation Administration (FAA), PHI, and Rolls Royce examined the engine. The engine examination revealed signs of an uncontained engine failure near the area of the third stage turbine wheel. The engine was further disassembled and initial investigation confirmed that the third stage turbine wheel had failed, which caused rub on the peashooter, which caused the turbine spline adapter to fail, and subsequent failure of the first stage turbine wheel. The third stage turbine wheel was shipped to Rolls Royce, for further metallurgical examination.
A review of maintenance records revealed that the third stage turbine wheel (part number 6898663, serial number X536938) had accrued a total of 1,904.7-hours and 3, 208-cycles. The turbine had been overhauled 283-hours and 439-cycles prior to its failure, due to a lightning strike. The maintenance records reported that the turbine was zygloyed at that time.
The pilot held a commercial pilot certificate for rotorcraft-helicopter with a helicopter instrument rating. In addition, he was also a certificated flight instructor for rotorcraft-helicopter and instrument helicopter. The pilot held a current second-class FAA medical certificate and reported having accumulated a total of 1,855-hours, of which 139-hours were in the same make and model.
The pilot reported the weather as wind between 180 and 220 degrees at 20, gusting to 25 knots, visibility 10 miles, broken ceiling 2,000 feet, and seas 6 to 10 feet.