BENTON CITY, WA, USA
N11VH
Bell 47G-2
The non-certificated pilot, who had been building the helicopter for several years, had recorded a total of 5 hours of flight experience in 1988 and an additional 10 hours in 1999 (July 19th through August 24th). Although all his flight time had been logged as 'dual,' family members reported that a number of the eight flights conducted in 1999 (all in the accident helicopter), had been flown solo. An ear witness reported hearing the helicopter depart followed by a 'popping' sound and then silence. The witness then observed a plume of smoke. A mechanic stated that the pilot reported having engine problems and then borrowed a used carburetor and the pilot's logbook contained an entry dated 8/16/99 with the remark 'flight test changed carb running good.' The aircraft impacted terrain in a steep descent and wreckage distribution was confined to a small area. Minimal leading edge rotor blade damage was noted and the engine/rotor RPM indicator was observed to display '0' and '170' RPM respectively at the site. The center portion of the helicopter including the engine and transmission were heavily damaged in the post-crash fire.
HISTORY OF FLIGHT On August 26, 1999, approximately 1125 Pacific daylight time, a non-deregistered Bell 47G-2 helicopter, previously N11VH, being operated by the owner, was destroyed during a collision with terrain and subsequent post-crash fire approximately four miles southeast of Benton City, Washington. The owner, who was the sole occupant, was fatally injured. Visual meteorological conditions existed and no flight plan had been filed. The personal flight was to have been operated under the provisions of 14CFR91, and originated from the owner's residence earlier in the morning. There were no reported eyewitnesses to the accident. An ear witness reported hearing the rotorcraft depart from her neighbor's property and subsequently heard a "popping" sound followed by silence. She then looked west and observed a smoke plume (refer to ATTACHMENT FAA I). PERSONNEL INFORMATION The pilot's family provided a single flight logbook which was examined. The cover page of the logbook contained no pilot certificate information and was annotated as "log book #1." The logbook's first two pages contained written entries for 13 individual flights with the first flight dated 2/21/88, and the last dated 8/24/99. The first five flights, flown in a Hiller FH-1100 rotorcraft between 2/21/88 and 4/15/88, totaled 5.1 hours of flight time (all logged as dual). The remaining eight flights, flown in N11VH between 7/19/99 and 8/24/99, totaled 10.0 hours (all logged as dual). Refer to TABLE I for a breakdown of the pilot's logbook. There was no record of the pilot possessing a student pilot or any other pilot certificate. Additionally, there was no record of the pilot possessing a Federal Aviation Administration (FAA) medical certificate. According to an FAA inspector from the Spokane Flight Standards District Office (FSDO), family members reported that the pilot had been building the helicopter for several years, and that he had flown a number of solo flights within the previous month prior to the accident (refer to ATTACHMENT FAA I). AIRCRAFT INFORMATION N11VH, a Bell 47G-2, serial number 2027, and originally manufactured in 1958, was last registered under a restricted category to Valicopters, Inc. FAA records indicated that the last certificate action associated with the aircraft was dated 03/31/1994. According to the Spokane FAA FSDO inspector, Valicopters had gone out of business some years earlier, and N11VH had never been de-registered. The inspector interviewed a mechanic who reported that the pilot had reported engine problems. He then borrowed a used carburetor from the mechanic (refer to ATTACHMENT FAA I). The pilot's logbook contained an entry for a flight in N11VH dated 08/16/99, which contained the written remark "Flight test changed carb running good" (refer to TABLE I). No aircraft or engine logs could be located, nor was any paperwork located relating to the application of a supplemental type certificate allowing removal of the rotorcraft's stabilizer bar. WRECKAGE AND IMPACT INFORMATION The aircraft crashed in an asparagus field approximately 1.7 miles east of the intersection of Weber Canyon Road and Badger Road, and slightly south of Badger Road (refer to CHART I). The accident site coordinates were approximately 46 degrees 13.9 minutes north latitude and 119 degrees 25.6 minutes west longitude. The rotorcraft was observed by the FAA inspector to have come to rest on its left side, and approximately 15 feet west of a ground impact impression similar to the shape of the rotor hub assembly. A post-crash fire consumed the center section of the rotorcraft, including the engine and transmission. All major components were found at the ground impact site. Both main rotor blades remained attached to the hub assembly. One blade displayed upwards bending deformation, some trailing-edge buckling deformation, and minimal leading edge deformation (refer to photograph 1). The opposing blade displayed a lesser degree of downwards bending deformation, extensive trailing-edge buckling deformation and skin delamination, and minimal leading edge deformation (refer to photograph 2). The main rotor hub assembly was observed to be modified for operation without a stabilizer bar assembly, and the rotor blade displaying downwards bending deformation was observed to have rotated into a near reverse (180 degree) position. Its pitch-link push rod was observed to be broken approximately midspan (refer to photographs 3 and 4). The aft end of the tail rotor drive shaft, including the 90 degree gearbox and tail rotor assembly, was observed to be separated from the tail boom assembly. Both tail rotor blades remained attached to the 90 degree gearbox (refer to photograph 5). The FAA inspector reported that one tail rotor blade (part number 642-102-053) was identified with serial number A379256. The opposing tail rotor blade (part number 047-642-102-053) was identified with serial number A375325. The tail rotor blades were not a matched pair. The FAA inspector also reported that he could find no aircraft data plate in the wreckage. He did locate a scorched area of skin with a taped registration number (refer to photograph 6). He also reported identifying the Lycoming VO-435-A1G reciprocating engine as serial number RL1231-31, and determined that the carburetor inlet screen was clear of obstructing material. An examination of the instrument panel revealed engine RPM of "0" and rotor RPM of "170" (refer to photograph 7 and ATTACHMENT FAA I). MEDICAL AND PATHOLOGICAL INFORMATION Post-mortem examination of the pilot was conducted by Daniel Selove, M.D., at Einan's Funeral Home, Richland, Washington, on August 27, 1999, (Benton County Coroner case number C-393-99). Toxicological evaluation of samples from the pilot was conducted by the FAA's Toxicology Accident and Research Laboratory, Oklahoma City, Oklahoma. All test results were found to be negative (refer to attached report). ADDITIONAL INFORMATION On-site examination of the wreckage and site was conducted on August 26/27, 1999, by the previously referenced Spokane FAA FSDO inspector, who subsequently released the wreckage to family members.
A loss of power for undetermined reasons and the failure of the pilot to maintain adequate rotor RPM following the power loss. Contributing factors were the pilot's lack of certification and total experience.
Source: NTSB Aviation Accident Database
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