# NTSB WPR10CA364: Bell 206 B II, N788BD, Big Bear City, CA, July 24, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: July 24, 2010, 10:25 local (17:25 UTC) - Place: Big Bear City, CA - Coordinates: 34.258056, -116.853614 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.2581&lon=-116.8536&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report December 20, 2010 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration FSDO - NTSB case key (mKey): 76736 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10CA364 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/76736/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=76736 - Page: https://openairdocs.org/ntsb/WPR10CA364 ## Probable cause The pilot's failure to maintain directional control during the landing approach. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Bell 206B II, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=1181505), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Temp/humidity/pressure: high density altitude](https://openairdocs.org/ntsb-findings/03031020): Environmental issues › Conditions/weather/phenomena · Effect on equipment; cases with it: [Bell 206B II, 1 case](https://openairdocs.org/ntsb-findings/03031020/cases.md?model=1181505), [All aircraft, 278 cases](https://openairdocs.org/ntsb-findings/03031020/cases.md) - [Performance/control parameters: yaw control](https://openairdocs.org/ntsb-findings/01062024): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Bell 206B II, 1 case](https://openairdocs.org/ntsb-findings/01062024/cases.md?model=1181505), [All aircraft, 149 cases](https://openairdocs.org/ntsb-findings/01062024/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242) (defining event); cases with it: [Bell 206B II, 1 case](https://openairdocs.org/ntsb-events/242/sequence.md?model=1181505), [All aircraft, 100 cases](https://openairdocs.org/ntsb-events/242/sequence.md) - [Approach: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Bell 206B II, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=1181505), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Bell 206B II, 2 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1181505), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter pilot was approaching the airport for landing about 350 feet above ground level when a fixed-wing airplane taxied in front of his intended landing spot and stopped. He slowed the helicopter to avoid blowing the airplane and the helicopter subsequently lost tail rotor effectiveness. The helicopter then rapidly descended to the ground and came to rest in a drainage depression. The helicopter sustained substantial damage to the fuselage and tail boom during the accident sequence and the pilot was not injured. The airport elevation was 6,572 feet mean sea level (msl) and the calculated density altitude at the time of the accident was about 9,300 feet msl. The pilot reported no mechanical malfunctions or failures with the helicopter and further stated that he could have prevented the accident by avoiding slow speeds at high density altitudes. ## Factual narrative The pilot was approaching the airport for landing about 350 feet above ground level when a fixed wing airplane taxied in front of his intended landing spot, and stopped. He slowed the helicopter to avoid blowing the airplane, and subsequently the helicopter lost tail rotor effectiveness. The helicopter then rapidly descended to the ground and came to rest in a drainage depression. The helicopter sustained substantial damage to the fuselage and tail boom during the accident sequence, and the pilot was not injured. The airport elevation was 6,572 feet mean sea level (msl), and the calculated density altitude at the time of the accident was about 9,300 feet msl. The pilot reported no mechanical malfunctions or failures with the helicopter, and further stated that he could have prevented the accident by avoiding slow speeds at high density altitudes. ## Aircraft - Registration: [N788BD](https://openairdocs.org/deregistered/N788BD-2015-05-19), registration cancelled 2015-05-19, S/N 1726, built 1975 (OpenAirDocs) - Reported make and model: BELL 206 B II - Registry model: [Bell 206B II](https://openairdocs.org/model/bell-206b-ii) (registry code 1181505) (OpenAirDocs) - Registry engine: [Allison 250-C20B](https://openairdocs.org/engine/allison-250-c20b) (registry code 03081, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 1726 - Airframe hours: 23449 - Engines: ALLISON 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 24, 2009, 15 hours before - Departed: POC, La Verne, CA - Destination: L35, Big Bear City, CA - Airport: L35, Big Bear City, runway 08, 5,850 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 71; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; medical: class 3, without waivers/limitations; last flight review January 27, 2010; seat: right; flight hours: 6,680 total, 3,500 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 10° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 12,000 ft overcast - Temperature: 81 °F, dew point 39 °F - Altimeter: 30.26 inHg - Observed at: L35 ## 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 20100724040409A](https://openairdocs.org/incident/20100724040409A), Jul 24, 2010: Bell 206 B II, Big Bear City, CA, Substantial damage. Established out of ground effect hover. Tail rotor lost effectiveness. Aircraft made 3 clockwise rotations prior to impact with the ground ## Docket (1 files) The files NTSB released with the investigation on August 16, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=76736. 1.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40334818&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF 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.