# NTSB SEA02TA164: Bell 206L-1, N832AH, Wisdom, MT, August 24, 2002 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: August 24, 2002, 16:00 local (22:00 UTC) - Place: Wisdom, MT - Coordinates: 45.622222, -113.504722 - Nearby events: https://openairdocs.org/map.md?lat=45.6222&lon=-113.5047&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report April 8, 2003 - Report: Approved by Office Director - Parties: FAA-FSDO, USDA Forest Service - NTSB case key (mKey): 55560 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA02TA164 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/55560/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=55560 - Page: https://openairdocs.org/ntsb/SEA02TA164 ## Probable cause The pilot's failure to maintain clearance from an object while maneuvering. A tree(s) was a factor. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, maneuvering - clearance - not maintained, pilot in command (cause) - object - tree(s) (contributing factor) ## Analysis The pilot reported that during a post-flight walk around, he noticed damage to the main rotor blades. One blade was punctured and both blades displayed tearing to the underside material of the blade. The pilot reported that several missions had been flown that day and he was unsure as to when the damage occurred. The pilot stated, that he believed that during one water drop with the 50-foot long line that held the water bucket, that the altitude was insufficient to avoid contact with an unseen tree top on the opposite side of the aircraft from the pilot station. ## Factual narrative On August 24, 2002, about 1600 mountain daylight time, a Bell 206L-1, N832AH, registered to Hillsboro Aviation, operated by the U.S.D.A. Forest Service as a public use firefighting flight, collided with tree(s) located about 18 miles west of Wisdom, Montana. Visual meteorological conditions prevailed at the time and company visual flight following was in effect. The helicopter was substantially damaged and the commercial pilot, the sole occupant, was not injured. The flight had been operating in the area all day. During a post-flight walk around, the pilot noticed damage to both main rotor blades. One blade was punctured and both blades displayed tearing to the underside material of the blade. The pilot reported that several missions had been flown that day and he was unsure as to when the damage occurred. The pilot stated, "I believe that during one water drop the aircraft's altitude was insufficient to avoid contact with an unseen tree top which rose into the rotor near the opposite side of the aircraft from the pilot station. This tree top would have been taller than the surrounding timber." The pilot reported no mechanical failures or malfunctions with the aircraft at the time, and that he felt no vibration, heard no noise, or noticed any change in rpm. USFS personnel reported that it appeared that during the second to the last flight of the day, while the pilot was supporting firefighting personnel on the ground, the pilot descended into the trees with the 50-foot long line that held the water bucket. During this maneuver, the main rotor blades came in contact with tree(s). ## Aircraft - Registration: N832AH (not matched to a registry record) - Reported make and model: Bell 206L-1 - Category: Helicopter - Serial number: 45560 - Airframe hours: 6212 - Engines: Allison 250 C30P 525 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft, Public use - Operator: Usfs - Registered owner: Hillsboro Aviation - Airworthiness certificate: Special, Restricted (Special) - Last inspection: AAIP, July 29, 2002, 36 hours before - Departed: Wisdom, MT - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 27; injuries: none; flight instructor, commercial; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; last flight review May 30, 2002; seat: right; flight hours: 3,300 total, 1,000 in this make and model, 3,200 as pilot in command, 85 in the last 90 days, 42 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 25 statute miles - Lowest ceiling: none - Temperature: 54 °F ## Docket (7 files) The files NTSB released with the investigation on December 23, 2002, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=55560. 3.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 307 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448071&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 2, .PDF, 90 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448072&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Master.PDF - Photo 1. Red blade lower closeup. Digital photo. (item 3, .PDF, 765 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40173877&FileExtension=.PDF&FileName=Photo%201.%20%20Red%20blade%20lower%20closeup.%20%20Digital%20photo.-Master.PDF - Photo 2. Red blade lower. Digital photo. (item 4, .PDF, 762 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40173878&FileExtension=.PDF&FileName=Photo%202.%20%20Red%20blade%20lower.%20%20Digital%20photo.-Master.PDF - Photo 3. Red blade upper. Digital photo. (item 5, .PDF, 667 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40173879&FileExtension=.PDF&FileName=Photo%203.%20%20Red%20blade%20upper.%20%20Digital%20photo.-Master.PDF - Photo 4. White blade lower. Digital photo. (item 6, .PDF, 686 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40173880&FileExtension=.PDF&FileName=Photo%204.%20%20White%20blade%20lower.%20%20Digital%20photo.-Master.PDF - Photo 5. White blade upper. Digital photo. (item 7, .PDF, 613 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40173881&FileExtension=.PDF&FileName=Photo%205.%20%20White%20blade%20upper.%20%20Digital%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.