SEA99LA149

NTSB accident investigation · Bell 47G-2 · Benton City, WA · August 26, 1999

Accident · FatalLimited investigationFinal report
Date
August 26, 1999, 11:25 local (18:25 UTC)
Place
Benton City, WA
Injuries
1 fatal
Damage
Destroyed
Phase of flight
Unknown
Aircraft
N11VHBell 47G-2
Weather
Visual (VMC) · Day
Status
Completed · report November 2, 2000
Report
Approved by Office Director
FAA report
19990826042619A
Case key
47175

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

The NTSB’s determination of the probable cause, and any contributing factors.

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.

Analysis

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.

Factual narrative

The factual narrative950 words

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.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine powerUnknown
Reason for occurrence undeterminedCause
Loss of control - in flightUnknown
Rotor rpm - not maintainedPilot in commandCause
Lack of certificationPilot in commandFactor
Lack of total experiencePilot in commandFactor
In flight collision with terrain/waterDescent - uncontrolled

Aircraft

Registration
N11VH
Reported as
Bell 47G-2
Category
Helicopter
Serial number
2027
Engine
Lycoming VO-435-A1G, 260 horsepower, reciprocating
Damage
Destroyed
Fire
On-Ground
Flight
Personal · Part 91
Operator
Beightol, Steven, L.
Airworthiness certificate
Special, Restricted (Special)
Departed
WA

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
47
Seat
Left
Toxicology
Performed
Flight hours
15 total · 10 in this make and model · 10 in the last 90 days · 8 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
290° at 4 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
81 °F, dew point 55 °F
Altimeter
29.00 inHg
Observed at
PSC, 13 nm away

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.

Other investigations on N11VH · 6

Matched to the same aircraft by N-number and date.

NTSB SEA86LA143Accident · No injuriesLimited investigationFinal reportZillah, WAEn route to the local spray area a total loss of power occurred along with a loss of oil pressure. The acft was aprx 200 ft AGL over a pear orchard. The plt was attempting to autorotate onto a nearby road but the left skid caught the roof top of a metal shed.…Jun 12, 1986 · DestroyedNTSB SEA85LA155Accident · No injuriesLimited investigationFinal reportRoosevelt, WAA total loss of power occurred while on a CFR 137 flight, due to fuel exhaustion. Although the fuel gauge showed 1/2 tank of fuel, the pilot failed to visually check the fuel prior to this flight. During autorotation onto a wheat field a hard landing occurred…Jul 2, 1985 · Substantial damageNTSB SEA84LA132Accident · No injuriesLimited investigationFinal reportBuena, WAMain rotor blades contacted a wind machine during an aerial application flt. Helicopter settled into trees and rolled over. Plt said he knew the machine was there but had forgotten.Jun 14, 1984 · Substantial damageNTSB SEA82DA072Accident · No injuriesFinal reportGrandview, WAWhile dispensing herbicide (systox) over an apple orchard the pilot sensed that the engine was binding followed by a power loss. The pilot elected to dump the herbicide and performed a power-off autorotation landing in a grape vineyard. Investigation revealed…May 18, 1982 · Substantial damageNTSB SEA82DA050Accident · No injuriesFinal reportLyle, WADuring takeoff with a load of fertilizer, insufficient power was available to maintain engine and rotor RPM and sustain flight. The pilot dumped the load, but was unable to avoid ground contact. The tail rotor struck first and separated from the aircraft. The…Apr 10, 1982 · Substantial damageNTSB FTW74FPJ06Accident · 1 fatalClosedSpringer, OKAug 16, 1973 · Substantial damage