# NTSB CEN21LA153: Eurocopter EC130, N259AM, Tulsa, OK, February 25, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: February 24, 2021, 22:59 local (Feb 25, 2021, 04:59 UTC) - Place: Tulsa, OK · airport taxiway - Coordinates: 36.039584, -95.984595 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.0396&lon=-95.9846&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - Parties: Federal Aviation Administration, Oklahoma City FSDO, Air Methods - NTSB case key (mKey): 102733 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA153 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102733/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102733 - Page: https://openairdocs.org/ntsb/CEN21LA153 ## Probable cause The pilot’s improper decision to approach the airport and enter a low altitude hover with a gusting quartering tailwind, which resulted in a loss of tail rotor effectiveness during a turn at a low altitude. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: yaw control](https://openairdocs.org/ntsb-findings/01062024): Aircraft › Aircraft oper/perf/capability · Capability exceeded (probable cause); cases with it: [Eurocopter EC 130 B4, 2 cases](https://openairdocs.org/ntsb-findings/01062024/cases.md?model=8680989), [All aircraft, 149 cases](https://openairdocs.org/ntsb-findings/01062024/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Eurocopter EC 130 B4, 5 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=8680989), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Eurocopter EC 130 B4, 6 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=8680989), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Decision related to condition (probable cause); cases with it: [Eurocopter EC 130 B4, 3 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=8680989), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) - [Wind: gusts](https://openairdocs.org/ntsb-findings/03034045): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Eurocopter EC 130 B4, 1 case](https://openairdocs.org/ntsb-findings/03034045/cases.md?model=8680989), [All aircraft, 1,199 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md) - [Wind: gusts](https://openairdocs.org/ntsb-findings/03034045): Environmental issues › Conditions/weather/phenomena · Ability to respond/compensate (probable cause); cases with it: [Eurocopter EC 130 B4, 1 case](https://openairdocs.org/ntsb-findings/03034045/cases.md?model=8680989), [All aircraft, 1,199 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Loss of tail rotor effectiveness](https://openairdocs.org/ntsb-events/242) (defining event); cases with it: [Eurocopter EC 130 B4, 2 cases](https://openairdocs.org/ntsb-events/242/sequence.md?model=8680989), [All aircraft, 100 cases](https://openairdocs.org/ntsb-events/242/sequence.md) - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Eurocopter EC 130 B4, 5 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=8680989), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis After a west-southwest approach to the airport the pilot entered a low altitude hover near a taxiway intersection where he intended to turn left and join a north/south taxiway before continuing in a hover taxi south toward the ramp. During the counterclockwise turn to join the taxiway, the helicopter’s yaw rate increased as the tail passed through the north-northeast wind. The pilot allowed the helicopter to continue in the turn, despite an increasing left yaw rate, until the nose of the helicopter had realigned with the wind. However, at that point, he was unable to stop the counterclockwise rotation and the helicopter completed at least 2 revolutions before a landing skid struck the ground and the helicopter spun off the taxiway into a grass easement. The pilot and two medical personnel were not injured. The horizontal stabilizer attach fitting on the tail boom was fractured and required replacement. The operator did not report any mechanical malfunctions with the helicopter that would have precluded normal operation. According to a weather report issued about 6 minutes before the accident, the surface wind at the airport was from north-northeast at 8 knots. During the subsequent hour, the wind direction remained unchanged, but the wind speed had increased to 11 knots with 17 knot gusts. A loss of tail rotor effectiveness likely occurred when the helicopter encountered a wind gust during the left turn, which resulted in an increasing counterclockwise yaw rate that the pilot was unable to control. ## Aircraft - Registration: [N259AM](https://openairdocs.org/aircraft/N259AM), registered now, S/N 7050, built 2011 (OpenAirDocs) - Reported make and model: EUROCOPTER EC130 (B4) - Registry model: [Eurocopter EC 130 B4](https://openairdocs.org/model/eurocopter-ec-130-b4) (registry code 8680989) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-2B1](https://openairdocs.org/engine/turbomeca-arriel-2b1) (registry code 60056, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 7050 - Year built: 2011 - Airframe hours: 4050.4 - Engines: Turbomeca Arriel 2B1 747 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 135 - Operator: Air Methods Corporation - Registered owner: Air Methods Corporation - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, February 24, 2021 - Departed: 4OK3, Tulsa, OK - Destination: Same as departure - Flight plan: VFR - Airport: RVS, Richard Lloyd Jones, Jr. - Equipment: ADS-B, Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, without waivers/limitations; last flight review April 5, 2020; seat: left; flight hours: 4,587 total, 451 in this make and model, 18 in the last 90 days, 9 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 20° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 43 °F, dew point 30 °F - Altimeter: 30.29 inHg - Observed at: RVS - METAR: METAR KRVS 250453Z AUTO 02008KT 10SM CLR 06/M01 A3029 RMK AO2 SLP263 T00611006= ## Docket (9 files) The files NTSB released with the investigation on August 26, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102733. 7.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 3.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12576140&FileExtension=pdf&FileName=01%20-%20Accident%20Report_Redacted-Rel.pdf - Pilot statement (ben walker) (item 2, PDF, 1 page, 215 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12575828&FileExtension=pdf&FileName=02%20-%20Ben%20Walker%20(Pilot)%20Statement-Rel.pdf - Medical personnel statement (blake vowel) (item 3, PDF, 2 pages, 196 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12575480&FileExtension=pdf&FileName=03%20-%20Blake%20Vowel%20(Medical%20Personnel)%20Statement-Rel.pdf - Medical personnel statement (matthew george) (item 4, PDF, 1 page, 50 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12576150&FileExtension=pdf&FileName=04%20-%20Matthew%20George%20(Medical%20Personnel)%20Statement_Redacted-Rel.pdf - NTSB email to air methods concerning substantial damage assessment (item 5, PDF, 2 pages, 320 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12575353&FileExtension=pdf&FileName=05%20-%20NTSB%20email%20to%20Air%20Methods%20Concerning%20Substantial%20Damage%20Assessment_Redacted-Rel.pdf - Plots of FAA ADS-B track data (item 6, PDF, 2 pages, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12575838&FileExtension=pdf&FileName=06%20-%20Plots%20of%20FAA%20ADS-B%20Track%20Data-Rel.pdf - Airport layout diagram (rvs) (item 7, PDF, 1 page, 101 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12575490&FileExtension=pdf&FileName=07%20-%20Airport%20Layout%20Diagram%20(RVS)_Print-Rel.pdf - Weather reports (rvs) (item 8, PDF, 1 page, 106 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12576160&FileExtension=pdf&FileName=08%20-%20Weather%20Reports%20(RVS)-Rel.pdf - Photo (item 9, PDF, 1 page, 784 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12575363&FileExtension=pdf&FileName=09%20-%20Photo-Rel.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.