# NTSB LAX00LA239: Bell UH-1B, N807SB, Arbuckle, CA, June 23, 2000 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: June 23, 2000, 04:30 local (11:30 UTC) - Place: Arbuckle, CA - Coordinates: 39.020038, -122.039436 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.0200&lon=-122.0394&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report September 26, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 49503 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX00LA239 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/49503/pdf - Page: https://openairdocs.org/ntsb/LAX00LA239 ## Probable cause the partial failure of the tail rotor pitch change control rod that resulted in an attempted run-on landing in dark night conditions. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, maneuvering - aerial application - light condition - dark night (contributing factor) - rotor system,tail rotor hub pitch actuating shaft - failure,partial (contributing factor) - run on landing - attempted, pilot in command - maintenance - improper, company maintenance personnel (cause) - In flight collision with terrain/water, descent - uncontrolled ## Analysis The helicopter pilot took off about 0415 from a chemical loading site, made a left turn, and departed to spray a sunflower field. Subsequently the wreckage was located 1/2 mile west of the field. The helicopter collided with level farm terrain while in a descent. The horizontal and vertical stabilizers and tail rotor assembly appeared to be undamaged. The main rotor mast had rotated about 45 degrees forward, and symmetrical upward crushing of the cabin area occurred. A postaccident examination of the helicopter was conducted. The anti-torque control system examination revealed a tail rotor pitch change shaft's AN320 castellated shear nut stripped from the rotor end of the shaft. The threads were still intact on the shaft but missing from the nut. The shaft cotter pin hole retained the sheared portions of the cotter pin. The shearing force came from an unknown source. An ongoing wear imprint from the shaft end, into the castle nut, was noted by the lab report. Nut damage to the interior of the pitch change cap was also found during the wreckage examination. ## Factual narrative On June 23, 2000, about 0430 hours Pacific daylight time, a Bell, UH-1B, N807SB, collided with terrain near Arbuckle, California. The helicopter, operated by Pacific Valley Aviation under 14 CFR Part 137 as an aerial application flight, was destroyed. The commercial pilot was fatally injured. The operator reported visual meteorological conditions for the operation and a company flight plan was filed. The flight originated from a chemical loading site about 0415. A worker reported that the pilot took off from the loading truck, made a left turn, and departed to the sunflower field that they were working . The wreckage was located 1/2 mile west of the field. None of the workers in the field reported hearing or seeing the helicopter go down, nor did they hear any distress calls on the company radio. A weather observation was obtained from Chico, California, about 46 miles north of the accident site. At the time of the occurrence (0430), the observation was reporting visibility 2 miles; temperature 59 degrees Fahrenheit; dew point 57 degrees Fahrenheit; and calm wind conditions. A postaccident examination of the helicopter was conducted. The anti-torque control system examination revealed a tail rotor pitch change shaft's AN320 castellated shear nut stripped from the rotor end of the shaft. The threads were still intact on the shaft but missing from the nut. The shaft cotter pin hole retained the sheared portions of the cotter pin. The shearing force came from an unknown source. An ongoing wear imprint from the shaft end into the AN320 castle shear nut was noted by a laboratory report. Nut damage to the interior of the pitch change cap was also found during the wreckage examination. According to the Federal Aviation Administration inspector, it appeared the helicopter collided with level farm terrain while in a gradual level descent. The horizontal and vertical stabilizers and tail rotor assembly appeared to be undamaged. The main rotor mast had rotated about 45 degrees forward, and symmetrical upward crushing of the cabin area occurred. A laboratory report provided by AIG Aviation Insurance is attached. The last documented 100-hour inspection occurred on April 22, 2000. ## Aircraft - Registration: [N807SB](https://openairdocs.org/deregistered/N807SB-2013-08-15), registration cancelled 2013-08-15, S/N 62-1960 (OpenAirDocs) - Reported make and model: Bell UH-1B - Registry model: [Bell UH-1B](https://openairdocs.org/model/bell-uh-1b) (registry code 1181410) (OpenAirDocs) - Category: Helicopter - Serial number: 62-1960 - Airframe hours: 4205 - Engines: Lycoming T53-L13B 1300 horsepower turbo shaft - Damage: Destroyed - Flight: Aerial application, Part 137 - Operator: Pacific Valley Aviation - Registered owner: James And Carol Miller - Airworthiness certificate: Special, Restricted (Special) - Last inspection: AAIP, June 19, 2000, 2 hours before - Departed: NONE, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; commercial; medical: class 2, valid medical--w/ waivers/lim; seat: right ## Weather - Conditions: Instrument (IMC), Night/dark - Visibility: 2 statute miles - Lowest ceiling: none - Temperature: 138 °F, dew point 135 °F - Altimeter: 29.00 inHg - Observed at: CIC, 46 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 (OpenAirDocs). - [Accident 20000623008869A](https://openairdocs.org/incident/20000623008869A), Jun 23, 2000: Bell UH1B, Williams, CA, No damage, 1 fatal. (-23) Heli crashed approx. 1/2 mile from departure point, the heli was operated by pacific valley aviation under part 137 14 CFR as a serial application… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.