# NTSB WPR10CA470: Bell 47G, N7860S, Gaston, OR, September 26, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: September 25, 2010, 19:00 local (Sep 26, 2010, 02:00 UTC) - Place: Gaston, OR - Coordinates: 45.435276, -123.136947 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.4353&lon=-123.1369&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 16, 2011 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 77404 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10CA470 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77404/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77404 - Page: https://openairdocs.org/ntsb/WPR10CA470 ## Probable cause The pilot's failure to maintain tail rotor clearance while landing on a transport trailer positioned on an uneven surface. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Object/animal/substance: ground vehicle](https://openairdocs.org/ntsb-findings/03022025): Environmental issues › Physical environment · Not specified; cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-findings/03022025/cases.md?model=1181028), [All aircraft, 132 cases](https://openairdocs.org/ntsb-findings/03022025/cases.md) - [Planning/preparation: flight planning/navigation](https://openairdocs.org/ntsb-findings/02061025): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-findings/02061025/cases.md?model=1181028), [All aircraft, 179 cases](https://openairdocs.org/ntsb-findings/02061025/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot; cases with it: [Bell 47G-3B-1, 6 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=1181028), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-flare/touchdown: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470) (defining event); cases with it: [Bell 47G-3B-1, 10 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1181028), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that he completed his last forest spray application for the day and was landing on a trailer used for transporting the helicopter. As the skids touched down on the trailer, he lowered the collective to the full down position. The helicopter abruptly tilted aft on the skid heals, and he applied up collective. The helicopter started to rotate to the right and he was unable to counter the rotation with the left anti-torque pedal. The pilot closed the throttle as the helicopter rotated 180 degrees to the right. The helicopter then contacted the side of the trailer and came to a full stop. The pilot reported that the trailer was parked on an uneven surface and that the slope and his abrupt movement of the collective resulted in the tail rotor coming into contact with the trailer. The pilot also felt that the accident could have been avoided if the trailer were on level terrain and he had waited to lower the collective until after establishing positive and complete skid contact with the surface of the trailer. The pilot reported no mechanical failures or malfunctions with the helicopter at the time of the accident. ## Factual narrative The pilot reported that he completed his last forest spray application for the day, and was landing on the trailer used for transporting the helicopter. He stated that he placed the landing skids on the trailer, and lowered the collective to the full down position. The helicopter abruptly tilted aft on the skid heals, and he applied up collective. The helicopter started to rotate to the right, and he was unable to counter the rotation with the left anti torque pedal. The pilot closed the throttle as the helicopter rotated 180 degrees to the right. The helicopter then contacted the side of the trailer, and came to a full stop. The engine was not running at this point, so he shut off the battery master switch, and disconnected the battery to avoid potential ignition of any fuel. The pilot reported that the trailer was parked on an uneven surface with the up side at the tail of the helicopter. He thought that the slope and his abrupt movement of the collective resulted in the tail rotor coming into contact with the trailer deck. The pilot also felt that the accident could have been avoided if the trailer were on level terrain, and he had waited to lower the collective until after establishing positive and complete full landing skid gear contact with the surface of the trailer. The pilot reported no mechanical failures or malfunctions with the helicopter at the time of the accident. ## Aircraft - Registration: [N7860S](https://openairdocs.org/aircraft/N7860S), registered now, S/N 6627 (OpenAirDocs) - Reported make and model: BELL 47G (3B1) - Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (OpenAirDocs) - Registry engine: [Allison 250 series](https://openairdocs.org/engine/allison-250-series) (registry code 03019, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 6627 - Airframe hours: 8871 - Engines: Rolls-Royce Allison 250 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Farm and Forest Helicopter Service, Inc. - Registered owner: Farm and Forest Helicopter Service, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, August 7, 2010 - Departed: Gaston, OR - Destination: Gaston, OR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; commercial, private; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review October 29, 2008; seat: left; flight hours: 3,600 total, 2,500 in this make and model, 3,500 as pilot in command, 239 in the last 90 days, 75 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 73 °F, dew point 57 °F - Altimeter: 29.97 inHg - Observed at: KHIO ## 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 20100925046309A](https://openairdocs.org/incident/20100925046309A), Sep 25, 2010: Bell 47G-3B-1, Gaston, OR, Substantial damage. The pilot stated "I was in the process of landing N8760S on the trailer used for over the road transportation of the helicopter. I placed the landing skids on… ## Other investigations on N7860S (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 SEA78FTA08](https://openairdocs.org/ntsb/SEA78FTA08), Dec 20, 1977: Bell 47G3B1 (N7860S), Billings, MT, destroyed ## Docket (1 files) The files NTSB released with the investigation on November 2, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77404. 444 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 444 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40337559&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.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.