Hosston, LA, USA
N313BG
Fairchild Hiller FH-1100
The commercial pilot and pilot rated passenger were on a 1,620-nautical mile cross-country flight following the purchase of the accident helicopter. Following a fuel stop, they had progressed approximately 180 miles when the helicopter's main rotor and rotor hub assembly separated from the upper mast. The helicopter subsequently entered an uncontrolled descent and impacted the ground. There were no eyewitnesses to the accident. Examination of the main rotor mast fracture surfaces revealed signatures consistent with mast bumping. Though there was evidence of a mast bumping event, the initiating event is unknown. Examination of the wreckage disclosed no anomalies that would have prevented normal system operation and the engine displayed evidence of rotation at the time of ground impact. The cockpit also exhibited damage consistent with main rotor contact. On the day of the accident, the outer bands of a tropical storm made landfall on the Louisiana coast. However, automated weather observing systems located inland near the accident site were reporting visual meteorological conditions at the time of the accident.
HISTORY OF FLIGHT On September 12, 2007, about 1830 central daylight time, a turbine powered Fairchild Hiller FH-1100 helicopter, N313BG, was destroyed when it collided with terrain while in cruise flight near Hosston, Louisiana. The commercial pilot and pilot rated passenger sustained fatal injuries. The airplane was registered to and operated by Leading Edge Helicopters Inc., of Boulder City, Nevada. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The 1,620-nautical mile cross-country flight originated from Century, Florida, and was destined for Boulder City Municipal Airport (61B), near Boulder City, Nevada. There were no eyewitnesses to the accident; however, one individual located two and three forth miles south east of the accident site, reported seeing a helicopter at tree top level flying in a north westerly direction approximately 1830. The witness reported that the helicopter "was not moving fast" and that she waved at the person seating on the right side of the helicopter as it passed over. Initially she thought the helicopter was going to land in her front yard. According to the president of Van Nevel Helicopters Inc, of Century, Florida, the pilot had purchased the helicopter from his company the day before and was returning to Boulder City, Nevada, when the accident occurred. PERSONNEL INFORMATION The pilot held a commercial certificate with ratings for helicopter land and instrument helicopter. He also held a certified flight instructor certificate. His last Federal Aviation Administration (FAA) second-class medical was issued on April 18, 2007, with no restrictions. Copies of the pilot's logbook were provided to the investigator-in-charge (IIC). As of the last entry, dated June 25, 2007, the pilot had accumulated a total flight time of 1,215 hours; of which 178 hours were in this make and model of helicopter. His last noted flight review was completed August 11, 2007. The pilot rated passenger held a private pilot certificate for helicopter land which he had received on November 11, 2006. His last Federal Aviation Administration (FAA) second-class medical was issued on May 25, 2006, with no restrictions. A review of his pilot logbook revealed that he had accumulated a total flight time of 127 hours; of which 1.2 hours were noted as instruction received in this make and model of helicopter. AIRCRAFT INFORMATION The helicopter was a Fairchild-Hiller FH-1100, serial number 190. The FH-1100 has a two-bladed rotor system and is powered by a single turbo shaft engine. The FH-1100 has a maximum gross weight of 2,750 lbs and can be configured to accommodate a pilot and three passengers. According to the helicopter's records, it was issued a FAA standard airworthiness certificate on September 4, 2007, and was certified for normal category operations. At the time of the accident, the helicopter had accumulated a total estimated airframe time of 2,185 hours. The last annual inspection was completed on July 15, 2007, and the helicopter had accumulated approximately 30 hours since the inspection and a complete refurbishment. The engine was a 420 horsepower Allison Engine 250-C20B, serial number CAE821765. The last engine annual inspection was completed on July 15, 2007. At the time of the accident the engine had accumulated approximately 2155.6 hours total time and about 30 hours since the last inspection. The last recorded fuel stop was at the Vicksburg Municipal Airport (VKS), located near Vicksburg, Mississippi, and approximately 180 miles southeast of the accident site. Fueling records revealed that the helicopter was serviced with 56-gallons of Jet A aviation fuel at 1617. METEOROLOGICAL INFORMATION On the day of the accident, the outer bands of tropical storm Humberto made landfall on the Louisiana coast. However, automated weather observing systems located inland near the accident site were reporting visual meteorological conditions at the time of the accident. At 1853, the automated weather observing system at the Shreveport Downtown Airport, (DTN), Shreveport, Louisiana, located 25 nautical miles southeast from the site of the accident, reported wind from 110 degrees at 4 knots, 10 statute miles visibility, scattered clouds at 3,100 feet, broken overcast at 4,400 feet, overcast at 8,500 feet, temperature 75 degrees Fahrenheit, dew point 66 degrees Fahrenheit, and a barometric pressure setting of 29.98 inches of Mercury. At 1853, the automated weather observing system at the East Texas Regional Airport (GGG), Longview, Texas, located 48 nautical miles southwest from the site of the accident, reported wind from 110 degrees at 6 knots, 10 statute miles visibility, overcast at 3,200 feet, temperature 75 degrees Fahrenheit, dew point 64 degrees Fahrenheit, and a barometric pressure setting of 29.98 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The helicopter impacted into wooded terrain and came to rest on its left side among pine trees. The Global Positioning System (GPS) coordinates recorded at the accident site were 32 degrees 52.529 minutes North latitude and 093 degrees 55.284 minutes West longitude, at a field elevation of approximately 190 feet mean sea level (msl). The wreckage debris field was approximately 330 feet in length oriented on a 345-degree magnetic heading. All major airframe components were accounted for at the wreckage site; however, the main rotor hub and blades were located approximately 308 feet from the main wreckage on a 198-degree magnetic heading. The main rotor blades remained attached to the rotor hub assembly. The main rotor mast was fractured adjacent to lower the edge of the rotor hub assembly. The cabin area was nearly consumed in the post crash fire. The engine compartment aft to the tail rotor exhibited extensive thermal damage. The tail rotor drive shaft and the main rotor drive shaft exhibited torsional yielding. Tail rotor continuity was established from the pedal bar aft to the tail rotor gear box. Continuity to the remainder of controls could not be established due to thermal damage. The right front seat, right seat anti torque pedal, right cyclic stick, and right front carpet, were located separate from the main wreckage. Damage to these components and to the leading edge of a main rotor blade was consistent with the main rotor blade impacting the cabin prior to ground impact. The engine was examined at Rolls-Royce Corporation in Indianapolis, Indiana, on December 21, 2007, with oversight provided by the investigator-in-charge (IIC). Rotational scoring of internal engine components along with the torsional yielding signatures exhibited on the tail rotor drive shaft and main rotor drive shaft were consisted with the engine producing power at the time of impact. The examination of the fractured main rotor mast revealed that the mast failed flush with the bottom surface of the main rotor teetering stop (P/N 24-51441-25). The top half of the mast was attached to the main rotor head assembly and the bottom half of the mast was attached to the transmission assembly. The normally circular cross-section of the mast was deformed into an oval shape where the failure occurred. The inside diameter of the mast adjacent to the fracture(s) (top and bottom halves) was painted light green (primer) and contained no visible defects or mechanical damage. The fracture surface(s) consisted entirely of 45° shear lips typical of ductile overload in wrought products with no evidence of a preexisting failure mechanism. The outside diameter of the mast adjacent to the fracture(s) was void of white paint (top coat) from one to two inches above and below the fracture(s) and contained mechanical damage where it contacted the main rotor teetering stop on the top half and where it contacted the droop stop bumper (P/N 24-51440-7) on the bottom half. Contact with the main rotor teetering stop on the top half and with the droop stop bumper on the bottom half resulted in deforming the mast into an oval shape as previously noted. The main rotor teetering stops and one of the droop stops (P/N 21-51440-21) contained mechanical damage where they contacted the top and bottom halves of the failed mast, respectively. The opposite droop stop was not recovered and its attach point with the main rotor teetering stop was fractured. This fracture was rough and grainy in appearance typical of ductile overload in castings. No evidence of a preexisting failure mechanism was noted. The main rotor mast fracture signatures where consistent with mast bumping. Though there was evidence of a mast bumping event, the initiating event is unknown. Examination of the wreckage disclosed no anomalies that would have prevented normal system operation. MEDICAL AND PATHOLOGICAL INFORMATION The Office of the Medical Examiner of Caddo Parish, located in Baton Rouge, Louisiana, performed an autopsy on the pilot on September 14, 2007. The cause of death was reported as multiple traumatic injuries. The FAA, Toxicology Accident Research Laboratory, located in Oklahoma City, Oklahoma, conducted toxicological testing on the pilot. The toxicology report stated no ethanol was detected in the liver or kidney, and no drugs were detected in the liver.
The in-flight separation of the main rotor mast while in cruise flight following a mast bumping event. The reason for the mast bumping event was not determined.
Source: NTSB Aviation Accident Database
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