# NTSB ERA23LA307: Bell 206, N9913K, Terra Alta, WV, July 21, 2023 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: July 21, 2023, 11:05 local (15:05 UTC) - Place: Terra Alta, WV - Coordinates: 39.455514, -79.592732 - Nearby events: https://openairdocs.org/map.md?lat=39.4555&lon=-79.5927&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: Serious injuries - Injuries: 2 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO, Transportation Safety Board of Canada - NTSB case key (mKey): 192695 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA23LA307 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192695/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192695 - Page: https://openairdocs.org/ntsb/ERA23LA307 ## Probable cause The pilot’s inability to maneuver the helicopter for recovery after experiencing a strong, unanticipated tailwind in a confined operating area, which resulted in a descent and subsequent impact with terrain. ## 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) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); 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) - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Bell 206B, 2 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=1181511), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Bell 206B, 4 cases](https://openairdocs.org/ntsb-events/400/sequence.md?model=1181511), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Bell 206B, 34 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=1181511), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) ## Analysis The pilot was operating the helicopter near maximum gross weight about 400 ft above ground level, following the terrain for an aerial observation flight. About 10 seconds into a descent, over a hilltop toward the next power transmission line, the helicopter encountered a strong tailwind. Noting a loss of airspeed, the pilot lowered the collective to gain airspeed; however, the helicopter continued to slow and descend. The pilot further lowered the collective and pushed the cyclic forward, but this was ineffective in increasing the helicopter’s airspeed. Given the low operating profile in the confined surveying location between power transmission lines and trees, the pilot did not have adequate space to compensate for the tailwind condition or turn the helicopter into the wind. Consequently, the helicopter continued to descend until it impacted the ground. The pilot reported that there were no preimpact mechanical malfunctions or failures of the helicopter that would have precluded normal operation and stated (and a review of meteorological data confirmed) that the stronger than anticipated tailwinds arrived before the forecasted time. ## Factual narrative On July 21, 2023, about 1105 eastern daylight time, a Bell 206B, N9913K, was substantially damaged when it was involved in an accident near Terra Alta, West Virginia. The pilot and a crewmember sustained serious injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 aerial observation flight. The pilot and equipment operator departed Morgantown Municipal Airport/Walter L Bill Hart Field (MGW), Morgantown, West Virginia, about 1039 to survey power transmission lines in the local area. The pilot was operating the helicopter near its maximum gross weight, at an altitude of 400 to 450 ft above ground level, and an airspeed of 45 knots. After completing one survey line, they topped a hill and were about 10 seconds into their descent, following the terrain toward the next power transmission line, when the pilot felt a "push." According to the pilot, the helicopter’s airspeed started to drop due to a tailwind, so he gently lowered the collective. The helicopter continued to descend and he noted that the airspeed had bled off to a value below effective translational lift. He pushed the cyclic forward for airspeed and further lowered the collective, with about 85% power applied; however, the helicopter continued to lose altitude and the helicopter's proximity to the power transmission lines and trees prevented him from being able to turn the helicopter into the wind to recover. Realizing that he could not recover, he hugged the tree line to avoid hitting the power lines. When the helicopter dropped below the trees, he pulled up on the collective to cushion the landing. The helicopter impacted the ground skids first and swung to the right. The pilot reported that he did not experience any mechanical malfunctions or failures with the helicopter during the accident flight. Examination of the accident site by a Federal Aviation Administration inspector revealed that the helicopter came to rest on its right side between the trees and the power transmission lines. Examination of the wreckage revealed that the cockpit was crushed, the skids had separated, and the main rotor had sheared off at the shaft. When asked about the weather that day, the pilot responded that they were not expecting that weather at that hour, and that the high wind had not been forecast to begin until 2 1/2 hours later. He added that they never flew if the gusts were greater than 15 knots. He was later informed that at the time of the accident the wind was gusting between 15 and 20 knots. The 1105 automated weather report from Garrett County Airport (2G4), Oakland, Maryland, located about 16 miles northeast of the accident site, included variable wind of 6 knots gusting to 13 knots. The Terminal Aerodrome Forecast (TAF) issued for MGW included westerly wind at 6 knots, increasing to 8 knots gusting to 16 knots at 1300. A High-Resolution Rapid Refresh (HRRR) model obtained from the NOAA Air Resource laboratory for the accident site area at 1100 indicated asurface wind from 290° at 9 knots with potential gusts to 15 knots. ## Aircraft - Registration: [N9913K](https://openairdocs.org/aircraft/N9913K), registered now, S/N 2055, built 1976 (OpenAirDocs) - Reported make and model: BELL 206 (B) - Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs) - Registry engine: [Allison 250 SER 400HP](https://openairdocs.org/engine/allison-250-ser-400hp) (registry code 03013, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 2055 - Year built: 1976 - Airframe hours: 13088 - Engines: Rolls Royce 250-C20B turbo shaft - Damage: Substantial damage - Flight: Aerial observation, Part 91 - Operator: Maine Helicopters Inc - Registered owner: Maine Helicopters Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, July 8, 2023, 33.1 hours before - Departed: MGW, Morgantown, WV - Destination: EKN, Elkins, WV - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 32; injuries: serious; commercial; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review April 28, 2023; seat: left; restraint: 4-point; flight hours: 1,389 total, 177 in this make and model, 1,337 as pilot in command, 123 in the last 90 days, 24 in the last 30 days - Cabin crew; age 41; injuries: serious; seat: rear ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 6 knots, gusting 13 - Visibility: 10 statute miles - Lowest ceiling: 1,100 ft broken - Temperature: 64 °F, dew point 63 °F - Altimeter: 29.96 inHg - Turbulence: Unknown - Observed at: 2G4, 14 nm away - METAR: METAR K2G4 211505Z AUTO VRB06G13KT 10SM FEW006 BKN011 BKN023 18/17 A2996 RMK AO2= ## 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 20230721008829A](https://openairdocs.org/incident/20230721008829A), Jul 21, 2023: Bell 206B, Terra Alta, WV, Destroyed. Transcribed from the pilots original written statement Started recording lidar on designated powerline. Heading southeast up into mountainous area. As we… ## Other investigations on N9913K (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 NYC96LA167](https://openairdocs.org/ntsb/NYC96LA167), Aug 13, 1996: Bell 206B (N9913K), Starks, ME, substantial damage. Probable cause: the pilot's improper decision to operate at slow airspeed, and close to the critical relative wind azimuth area in gusty, variable winds, which resulted in an inadvertent loss of tail rotor… ## Docket (7 files) The files NTSB released with the investigation on July 5, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192695. 7.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16357914&FileExtension=pdf&FileName=1.5%20ERA23LA307%206120%20Signed_Redacted-Rel.pdf - Pilot's statement (item 2, PDF, 6 pages, 180 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16357503&FileExtension=pdf&FileName=ERA23LA307%20Pilot%20Statements_Redacted-Rel.pdf - Memorandum of record - crewmember statement (item 3, PDF, 2 pages, 105 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16358165&FileExtension=pdf&FileName=ERA23LA307%20MOR%20Crewmember_Redacted-Rel.pdf - Weather reports and records (item 4, PDF, 11 pages, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16357924&FileExtension=pdf&FileName=ERA23LA307%20Meterological%20Reports-Rel.pdf - Photo array (item 5, PDF, 5 pages, 982 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16370667&FileExtension=pdf&FileName=ERA23LA307%20Photo%20Array-Rel.pdf - Flight track log (item 6, KMZ, 405 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16358511&FileExtension=kmz&FileName=TrackLog_EC53B4A1-BD24-46C0-A5C6-F900C41B7E95-Rel.kmz - Release of aircraft wreckage, NTSB form 6120.15 (item 7, PDF, 2 pages, 480 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16358888&FileExtension=pdf&FileName=ERA23LA307%20Signed%20Wreckage%20Release_Redacted-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.