# NTSB DEN02LA036: Bell 206B-III, N997GM, Leadville, CO, April 4, 2002 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 4, 2002, 14:00 local (21:00 UTC) - Place: Leadville, CO - Coordinates: 39.213333, -106.190002 - Nearby events: https://openairdocs.org/map.md?lat=39.2133&lon=-106.1900&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report September 20, 2002 - Report: Approved by Office Director - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 54459 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN02LA036 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/54459/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=54459 - Page: https://openairdocs.org/ntsb/DEN02LA036 ## Probable cause the pilot's inadvertent flight into adverse weather, which resulted in a collision with terrain. A contributing factor was the downdraft. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, maneuvering - flight into known adverse weather - inadvertent, pilot in command (cause) - weather condition - downdraft (contributing factor) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - rough/uneven ## Analysis The pilot, who was on a power line patrol in mountainous terrain, flew the helicopter 100 feet to the right of the power line and into a 10 to 18 knot headwind. Airspeed was between 70 and 80 knots, altitude was 400 feet above the ground, and power was between 70 to 80 percent torque. As he turned to continue following the power line, a "strong downdraft pushed the helicopter" into the ground despite his efforts to regain control. The helicopter struck snow-covered terrain and rolled over. ## Factual narrative On April 4, 2002, approximately 1400 mountain standard time, N997GM, a Bell 206B-III helicopter, operated by AeroWest Helicopters, Inc., of Corrales, New Mexico, was destroyed when it struck terrain during an uncontrolled descent 5 miles north of Leadville, Colorado. Both the commercial pilot and a passenger received minor injuries. Visual meteorological conditions prevailed, and no flight plan had been filed for the aerial observation flight being conducted under Title 14 CFR (Code of Federal Regulations) Part 91. The flight originated in Eagle, Colorado, approximately 1330. According to a written statement given to the Lake County Sheriff's Office, the pilot said he was patrolling a power line between Leadville and Breckenridge. He was about 100 feet to the right of the power line, flying east into a 10 to 18 knot headwind. Airspeed was between 70 and 80 knots, altitude was 400 feet above the ground, and power was between 70 to 80 percent torque. The power line turned north towards Mosquito Pass. As the pilot started the turn, a "strong downdraft pushed the helicopter" towards the ground. The LOW ROTOR RPM horn sounded and the pilot lowered the collective control to regain rotor rpm, and simultaneously moved the cyclic control forward and to the right to avoid the power lines. After rotor rpm was regained, the pilot increased torque to 100 to 103 percent "to keep the helicopter flying." He said the downdraft continued to push the helicopter towards the ground and the LOW ROTOR RPM horn continued sounding. The pilot said he "decreased collective with forward airspeed with the cyclic" in an attempt to fly out of the downdraft, but to no avail. The helicopter's aft skids struck snow-covered terrain and "dug in." The helicopter rolled "once or twice" and came to rest on the underside of the fuselage. ## Aircraft - Registration: [N997GM](https://openairdocs.org/deregistered/N997GM-2005-04-22), registration cancelled 2005-04-22, S/N 2366, built 1978 (OpenAirDocs) - Reported make and model: Bell 206B-III - Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs) - Registry engine: [Allison 250-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 2366 - Airframe hours: 8890 - Engines: Rolls Royce/Allison 250-C20B 420 horsepower turbo shaft - Damage: Destroyed - Flight: Aerial observation, Part 91 - Operator: AeroWest Management Services, Inc., doing business as AeroWest Helicopters, Inc. - Registered owner: Copter Lease LLC - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, January 17, 2002, 24 hours before - Departed: EGE, Eagle, CO - Destination: LXV, Leadville, CO - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; last flight review January 21, 2002; seat: right; flight hours: 2,453 total, 624 in this make and model, 2,203 as pilot in command, 104 in the last 90 days, 81 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 48 °F, dew point 10 °F - Altimeter: 30.25 inHg - Observed at: LXV, 5 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 20020404007759A](https://openairdocs.org/incident/20020404007759A), Apr 4, 2002: Bell 206B, Leadville, CO, No damage. (-23) While flying power line patrol at an altitude of 11,000 to about 12,000 feet asl (400 ft. AGL) encountered a down draft which exceeded the performance… ## Docket (2 files) The files NTSB released with the investigation on August 29, 2002, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=54459. 450 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 424 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40423348&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Supplement S (item 2, .PDF, 26 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40162645&FileExtension=.PDF&FileName=Supplement%20S-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.