# NTSB CEN12LA267: Bell 206B, N85RB, Valley Falls, KS, May 2, 2012 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 2, 2012, 09:20 local (14:20 UTC) - Place: Valley Falls, KS - Coordinates: 39.339851, -95.460609 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.3399&lon=-95.4606&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242) - Highest injury: Minor injuries - Injuries: 3 minor - Status: Completed, report August 29, 2012 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA FSDO - NTSB case key (mKey): 83546 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN12LA267 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/83546/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=83546 - Page: https://openairdocs.org/ntsb/CEN12LA267 ## Probable cause The pilot’s inadequate compensation for the wind conditions during a hover maneuver, which resulted in a loss of tail rotor effectiveness. ## 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, 45 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=1181511), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: prop/rotor parameters](https://openairdocs.org/ntsb-findings/01062052): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Bell 206B, 11 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md?model=1181511), [All aircraft, 182 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Not specified; cases with it: [Bell 206B, 5 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=1181511), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242) (defining event); cases with it: [Bell 206B, 13 cases](https://openairdocs.org/ntsb-events/242/sequence.md?model=1181511), [All aircraft, 100 cases](https://openairdocs.org/ntsb-events/242/sequence.md) - [Emergency descent: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Bell 206B, 32 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=1181511), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Bell 206B, 57 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1181511), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter, with the pilot and two passengers aboard, was hovering about 100 to 150 feet above ground level with a quartering tailwind. As the pilot turned the helicopter to the right, the helicopter started to spin, as reported by the pilot and several witnesses. He applied full left pedal and left forward cyclic, and slightly reduced power to stop the rotation. The pilot added that he sensed the loss of tail rotor effectiveness (LTE) and continued with the control inputs to fly out of the LTE. The pilot was unable to regain control of the helicopter before it impacted the ground. The pilot reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation. Based on the flight conditions at the time, the accident sequence is consistent with the helicopter encountering a LTE event. ## Factual narrative On May 2, 2012, about 0920 central daylight time, a Bell 206B Helicopter, N85RB, impacted terrain following a loss of control, near Valley Falls, Kansas. The commercial rated pilot and two passengers received minor injuries. The helicopter sustained substantial damage. The helicopter was registered to a private individual and operated by Hawkeye Helicopters, Ottawa, KS. Day visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 aerial observation flight. Several witnesses reported the helicopter “spinning” before the crash. The helicopter impacted the ground near a footpath, with trees on either side of the path. The helicopter came to rest on its left side, with the tailboom and left skid separated from the fuselage. The pilot stated that the engine continued to run for a brief time after the accident. The pilot reported that during a 100-150 agl (above ground level) hover, the helicopter started an uncommanded right turn. He applied left full pedal, left-forward cyclic, and a slight reduction of power, to stop the rotation. The pilot added that he sensed the loss of tailrotor effectiveness (LTE), and continued with the control inputs to fly out of the LTE. Unable to get the helicopter to stop rotating, the pilot elected to enter an autorotation aiming for an open area, between a row of trees. The responding Federal Aviation Administration (FAA) inspector stated that the pilot reported that during an out-of-ground hover, the helicopter had a quartering tailwind. The pilot initiated a right turn and the helicopter started to spin. The inspector added that the accident pilot had recently received his rotorcraft-helicopter rating based on prior military experience; however, the pilot did not have much recent helicopter experience. On the NTSB Pilot/Operator Aircraft Accident/Incident Report, 6120.1 form, the pilot reported a total of 2,398 flight hours in rotorcraft, with 2.1 hours in the accident make/model of helicopter. FAA Advisory Circular (AC) 90-95, Unanticipated Right Yaw in Helicopters, dated February 26, 1995 states that the loss of tail rotor effectiveness (LTE) is a critical, low-speed aerodynamic flight characteristic which could result in an uncommanded rapid yaw rate which does not subside of its own accord and, if not corrected, could result in the loss of aircraft control. It also states, "LTE is not related to a maintenance malfunction and may occur in varying degrees in all single main rotor helicopters at airspeeds less than 30 knots." Paragraph 6 of the AC covered conditions under which LTE may occur. It states: "Any maneuver which requires the pilot to operate in a high-power, low-airspeed environment with a left crosswind or tailwind creates an environment where unanticipated right yaw may occur." Paragraph 9 of the AC states: "When maneuvering between hover and 30 knots: (1) Avoid tailwinds. If loss of translational lift occurs, it will result in an increasedhigh power demand and an additional anti-torque requirement. (2) Avoid out of ground effect (OGE) hover and high power demand situations, such as low-speed downwind turns. (3) Be especially aware of wind direction and velocity when hovering in winds of about 8-12 knots (especially OGE). There are no strong indicators to the pilot of a reduction of translation lift. (4) Be aware that if considerable amount of left pedal is being maintained a sufficient amount of left pedal may not be available to counteract an unanticipated right yaw. (5) Be alert to changing aircraft flight and wind conditions which may be experienced when flying along ridge lines and around buildings. (6) Stay vigilant to power and wind conditions." ## Aircraft - Registration: [N85RB](https://openairdocs.org/aircraft/N85RB), registered now, S/N 831, built 1972 (OpenAirDocs) - Reported make and model: BELL 206B - Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs) - Registry engine: [Rolls-Royce 250-C20](https://openairdocs.org/engine/rolls-royce-250-c20) (registry code 54178, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 831 - Airframe hours: 17038 - Engines: ROLLS-ROYC 250-C20 400 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial observation, Part 91 - Operator: Hawkeye Helicopter - Registered owner: Scott John D - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 31, 2011 - Departed: KLWC, Lawrence, KS - Destination: KLWC, Lawrence, KS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 62; injuries: minor; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review May 2, 2012; seat: right; flight hours: 8,459 total, 2 in this make and model, 5,659 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 15 knots, gusting 21 - Visibility: 10 statute miles - Lowest ceiling: 2,400 ft overcast - Temperature: 75 °F, dew point 66 °F - Altimeter: 29.76 inHg - Observed at: KTOP, 20 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 20120502009059A](https://openairdocs.org/incident/20120502009059A), May 2, 2012: Bell 206B, Valley Falls, KS, Substantial damage. Aircraft departed lawrence, KS with one pilot and two passengers on board for the purpose of conducting pipeline patrol operations. According to the pilot's… ## Other investigations on N85RB (1) 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. - [NTSB CEN23LA237](https://openairdocs.org/ntsb/CEN23LA237), Jun 11, 2023: Bell 206B (N85RB), Pratt, KS, substantial damage. Probable cause: Fuel exhaustion due to the pilot’s inadequate preflight planning. ## Docket (5 files) The files NTSB released with the investigation on July 6, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=83546. 1.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 450 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370322&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Witness Statement (news article) (item 2, .PDF, 265 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370325&FileExtension=.PDF&FileName=Witness%20Statement%20(news%20article)-Master.PDF - Weather Reports and Records (item 3, .PDF, 177 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370323&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF - Memo (item 4, .PDF, 92 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370364&FileExtension=.PDF&FileName=Memo-Master.PDF - Photo: Damaged Helicopter (FAA photo) (item 5, .PDF, 128 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40370329&FileExtension=.PDF&FileName=Photo%3A%20Damaged%20Helicopter%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20(FAA%20photo)-Master.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.