N38FABell OH-58A

The pilot reported that he was conducting annual refresher training with a certified flight instructor. During a practice autorotation to runway 18, the helicopter descended below a nearby tree line and "dropped vertically." He stated that the helicopter descended so rapidly that he was unable to arrest the descent rate and the helicopter landed hard. The pilot reported the winds from 230 degrees at 10 knots with gusts to 19 knots at the time of the accident. He reported that, as the helicopter descended below treetop level, "…we lost all lift and wind advantage…" The hard landing resulted in a fractured tail boom. The pilots reported no mechanical malfunctions or failures that would have precluded normal operation.

On September 18, 2010, approximately 1550 central daylight time, a Bell OH58A, N38FA, operated by B&S Air, Inc., impacted terrain following a loss of engine power immediately after takeoff from a portable platform near Covington, Tennessee. Day visual meteorological conditions prevailed and no flight plan was filed for the aerial application flight conducted under the provisions of 14 Code of Federal Regulations Part 137. The helicopter received substantial damage and the certificated commercial pilot was not injured.

According to the operator and the pilot, the helicopter was refueled with approximately 165 pounds of fuel from a 500-gallon, stainless steel tank prior to the accident flight. The operator utilized that tank to refuel the helicopter for several days prior to the accident, including the 4 hours the helicopter flew the morning of the accident. During takeoff, about 30 feet above ground level and at approximately 30 mph, while at translational lift, the engine began "surging." The helicopter experienced a loss of engine power and began losing altitude. It impacted the ground "fairly hard" and the main rotor blades struck and severed the tail boom approximately 1 foot aft of the horizontal stabilizer.

According to the pilot and Federal Aviation Administration (FAA) records, the pilot, held a commercial pilot certificate with ratings for airplane single-engine land and rotorcraft-helicopter. His most recent FAA second-class medical certificate was issued on December 18, 2009 and at that time the pilot reported 20,000 total hours of flight experience. The pilot reported approximately 800 hours in the accident helicopter make and model.

The engine was removed from the helicopter and was examined at a facility near Coatesville, Pennsylvania on October 7 and 8, 2010. A pneumatic leak check was performed and no leaks were detected. An external examination of the engine was accomplished and no damage or abnormalities were noted. The oil and fuel filters were free of debris and the magnetic chip detectors were free of debris. The fuel nozzle was removed and appeared clean and displayed no carbon deposits. According to the FAA inspector that provided the oversight for the engine removal, the operator had disassembled the fuel nozzle and found some particles in an undetermined location within the nozzle. The particles were placed in sealed cans and were sent with the engine. The particles, as well as exemplar samples of the fuel lines similar in color and torque indicating paint utilized on the fuel line connector "B" nut, were sent to the Safety Board's Materials Laboratory for analysis. The engine was installed on a test stand and started normally. The engine was accelerated to the takeoff power setting with no hesitation or anomalies noted. The engine was operated according to the guidelines specified by Rolls-Royce with no anomalies noted. Several accelerations and decelerations were conducted at the end of the engine test as well as a governor droop check and no anomalies were noted or observed. Examination of the fuel nozzle after operation revealed carbon deposits on the surface.

The samples were examined by the Safety Board's Material Laboratory and it was determined that the material found in the fuel nozzle was torque stripe material.