# NTSB WPR24LA247: Bell 407, N21BH, Stanley, ID, July 11, 2024 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 4 · Limited · Final report - Date: July 11, 2024, 17:05 local (23:05 UTC) - Place: Stanley, ID - Coordinates: 44.116333, -114.956 - Nearby events: https://openairdocs.org/map.md?lat=44.1163&lon=-114.9560&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Windshear or thunderstorm](https://openairdocs.org/ntsb-events/390) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 194702 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR24LA247 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194702/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=194702 - Page: https://openairdocs.org/ntsb/WPR24LA247 ## Probable cause A sudden wind shift which resulted in a rapid descent and subsequent dynamic rollover and collision into water. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Bell 407, 2 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=1182206), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Windshear or thunderstorm](https://openairdocs.org/ntsb-events/390) (defining event); cases with it: [Bell 407, 1 case](https://openairdocs.org/ntsb-events/390/sequence.md?model=1182206), [All aircraft, 224 cases](https://openairdocs.org/ntsb-events/390/sequence.md) - [Maneuvering-hover: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Bell 407, 2 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=1182206), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Maneuvering-hover: External load event (Rotorcraft)](https://openairdocs.org/ntsb-events/480); cases with it: [Bell 407, 1 case](https://openairdocs.org/ntsb-events/480/sequence.md?model=1182206), [All aircraft, 51 cases](https://openairdocs.org/ntsb-events/480/sequence.md) - [Maneuvering-hover: Dynamic rollover](https://openairdocs.org/ntsb-events/231); cases with it: [Bell 407, 3 cases](https://openairdocs.org/ntsb-events/231/sequence.md?model=1182206), [All aircraft, 161 cases](https://openairdocs.org/ntsb-events/231/sequence.md) - [Maneuvering-hover: Settling with power/vortex ring state](https://openairdocs.org/ntsb-events/244); cases with it: [Bell 407, 1 case](https://openairdocs.org/ntsb-events/244/sequence.md?model=1182206), [All aircraft, 52 cases](https://openairdocs.org/ntsb-events/244/sequence.md) ## Analysis The pilot stated that he was conducting firefighting operations in a helicopter equipped with a 50-foot long-line and a 120-gallon Bambi bucket. Earlier in the day he performed 29 water pickups and returned to a nearby helibase to refuel. The pilot went back to the lake where he had performed the previous fills and completed 13 water pickups noting that the wind was increasing. He went to perform the 14th water pickup and entered a left downwind approach to the lake as he had done all day. On final approach, the helicopter encountered a wind shift, which resulted in a rapid rate of descent. The pilot attempted to arrest the descent by raising the collective which led to a settling with power event. The bucket impacted the water that resulted in a dynamic rollover and the helicopter nosed-in to the lake. The pilot stated that there were no pre impact mechanical failures or malfunctions that would have precluded normal operation. ## Aircraft - Registration: [N21BH](https://openairdocs.org/aircraft/N21BH), registered now, S/N 53262, built 1998 (OpenAirDocs) - Reported make and model: BELL 407 - Registry model: [Bell 407](https://openairdocs.org/model/bell-407) (registry code 1182206) (OpenAirDocs) - Registry engine: [Allison 250-C47 series](https://openairdocs.org/engine/allison-250-c47-series) (registry code 03029, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 53262 - Year built: 1998 - Airframe hours: 9045.5 - Engines: Rolls Royce 250-C47B 650 horsepower turbo shaft - Damage: Substantial damage - Flight: Firefighting, Public use - Operator: Brainerd Helicopter Services Inc. - Registered owner: Chemair Helicopters Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, July 1, 2024, 92 hours before - Departed: Stanley, ID - Destination: Stanley, ID - Equipment: Electronic flight bag or handheld device, Auto-pilot, ADS-B, Video recording device, Satellite tracking device, Handheld GPS, Onboard weather ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: minor; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 1, with waivers/limitations; last flight review January 22, 2024; seat: right; restraint: 4-point; flight hours: 4,327 total, 722 in this make and model, 4,143 as pilot in command, 10 in the last 90 days, 5 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 8 knots, gusting 18 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 88 °F, dew point 36 °F - Altimeter: 30.23 inHg - Turbulence: Light - Observed at: KSNT - METAR: METAR KSNT 112251Z AUTO 34008G18KT 31/02 A3023 RMK AO1 SLP132 T03110022= ## 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 20240711007499A](https://openairdocs.org/incident/20240711007499A), Jul 11, 2024: Bell 407, Stanley, ID, Substantial damage. Bell 407 helicopter was on a firefighting operation when it was attempting to refill the attached bucket with water from bench lake. The wind shifted/sheared… ## Docket (3 files) The files NTSB released with the investigation on March 6, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=194702. 15.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 8 pages, 14.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17727988&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Pilot statement from helitack superintendent (item 2, PDF, 2 pages, 139 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17727998&FileExtension=pdf&FileName=Pilot%20Statement-Rel.pdf - Picture of wreckage (provided by us forest service) (item 3, PDF, 1 page, 232 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17727668&FileExtension=pdf&FileName=Z-%20Attachment%2002%20-Photos-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.