# NTSB CEN19TA280: Bell 47G, N1170W, Montrose, CO, August 20, 2019 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Final report - Date: August 20, 2019, 10:30 local (16:30 UTC) - Place: Montrose, CO - Coordinates: 38, -107 - Nearby events: https://openairdocs.org/map.md?lat=38.0000&lon=-107.0000&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Fuel starvation](https://openairdocs.org/ntsb-events/191) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 100104 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN19TA280 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100104/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100104 - Page: https://openairdocs.org/ntsb/CEN19TA280 ## Probable cause A loss of engine power due to fuel starvation, which resulted from attitude-induced unporting of the fuel. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fluids: fuel](https://openairdocs.org/ntsb-findings/01071010): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Bell 47G-3B-1, 2 cases](https://openairdocs.org/ntsb-findings/01071010/cases.md?model=1181028), [All aircraft, 1,695 cases](https://openairdocs.org/ntsb-findings/01071010/cases.md) - [Fluids: fuel](https://openairdocs.org/ntsb-findings/01071010): Aircraft › Fluids/misc hardware · Related operating info (probable cause); cases with it: [Bell 47G-3B-1, 2 cases](https://openairdocs.org/ntsb-findings/01071010/cases.md?model=1181028), [All aircraft, 1,695 cases](https://openairdocs.org/ntsb-findings/01071010/cases.md) - [Fuel system: fuel distribution](https://openairdocs.org/ntsb-findings/01022820): Aircraft › Aircraft systems · Design (probable cause); cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-findings/01022820/cases.md?model=1181028), [All aircraft, 141 cases](https://openairdocs.org/ntsb-findings/01022820/cases.md) - [Fuel system: fuel distribution](https://openairdocs.org/ntsb-findings/01022820): Aircraft › Aircraft systems · Capability exceeded (probable cause); cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-findings/01022820/cases.md?model=1181028), [All aircraft, 141 cases](https://openairdocs.org/ntsb-findings/01022820/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: Fuel starvation](https://openairdocs.org/ntsb-events/191) (defining event); cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-events/191/sequence.md?model=1181028), [All aircraft, 733 cases](https://openairdocs.org/ntsb-events/191/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Bell 47G-3B-1, 3 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1181028), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis Before the pilot performed an aerial application, the helicopter was serviced with pesticide, but no fuel was added; fuel had been added before the three previous flights. During one of the aerial application passes, the engine lost power; the pilot conducted a forced landing to a field, and the helicopter’s tailboom and fuselage were substantially damaged. Following the accident, about 3/4 gallon of fuel was recovered from the right fuel tank and 2 1/2 gallons of fuel were recovered from the left fuel tank. There was no evidence of mechanical malfunction of failure that would have precluded normal engine operations. Each spray pass is made at an airspeed of about 85 mph and directly above the crop to achieve optimal product application and spray coverage to the crop. At that speed, the helicopter flies in a nose-low attitude. The fuel delivery port or tube on both tanks is located at the aft, lower end of each tank, and both tanks deliver fuel to the engine simultaneously. It is likely that the limited fuel in the tanks moved away from the fuel ports due to the helicopter's nose-low attitude, resulting in fuel starvation. ## Factual narrative On August 20, 2019, about 1030 mountain daylight time, a Bell 47G-3B-1, N1170W, lost engine power during aerial application near Montrose, Colorado. The commercial pilot was seriously injured, and the helicopter sustained substantial damage to the tail boom and fuselage. The helicopter was registered to and operated by Olathe Spray Service, Inc., Olathe, Colorado, as a Title 14 Code of Federal Regulations Part 137 aerial application flight. Visual meteorological conditions prevailed at the accident site and at the time of the accident, and no visual flight rules flight plan had been filed for the local flight. The local flight departed about 1000. The pilot stated that he had been performing agricultural spray operations in four different locations. He returned to Clifford Field Airport (1CO4), Olathe, Colorado, his home base, to take on additional chemical product. On the three previous trips, pesticide and about 30 gallons of Jet-A fuel were added as the helicopter sat idling. On this, the fourth trip, the helicopter was serviced with chemical, but no fuel was added. Each spray pass was performed about 85 mph and just above the crop in order to achieve optimal product application and spray coverage to the crop. In order to do this the helicopter, at that speed, was flown in a nose-low attitude. The fuel delivery port/tube on both tanks is located at the aft, lower end of each tank, and both tanks deliver fuel to the engine simultaneously. There is no pilot-controlled fuel selector valve in the cockpit. During the aerial application, the helicopter yawed left when the engine flamed out. The pilot slowed the airspeed and the helicopter impacted a cornfield. The helicopter had been resting on its right side in a corn field for several days before a Federal Aviation Administration (FAA) inspector and a representative of the engine manufacturer examined it. As a result, it could not be determined if fuel had drained out of the right fuel tank through a vent line, loose filler cap, or breached tank, but approximately 2/3 to 3/4 gallon of clean, clear, odor-free fuel was drained from of the right tank, and 2-1/2 gallons were drained from the left tank. Fuel was also found from the inlet side of the airframe-mounted fuel filter to the fuel spray nozzle inlet on the engine. The fuel spray nozzle appeared normal with no signs of excessive carbon deposits or blockage. Both the airframe and engine fuel filter bowls contained clean fuel, and both filters were void of contamination. N1 (gas producer) and N2 (power turbine) rotor continuity was confirmed, and both rotors turned smoothly when rotated by hand. Cockpit controls from the throttle and collective back to the engine fuel control unit and power turbine governor were free and continuous. The engine oil system, including the filter and magnetic plugs, was checked and was unremarkable. Further examination revealed no evidence of mechanical malfunction or pre-existing conditions that would haveprecluded normal engine operation. ## Aircraft - Registration: [N1170W](https://openairdocs.org/deregistered/N1170W-2021-08-12), registration cancelled 2021-08-12, S/N 2944, built 1965 (OpenAirDocs) - Reported make and model: Bell 47G (3B-1) - 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 03014, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 2944 - Year built: 1965 - Airframe hours: 13693 - Engines: Rolls-Royce 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Olathe Spray Service, Inc. - Registered owner: Olathe Spray Service, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, June 24, 2019 - Departed: 1CO4, Olathe, CO - Destination: 1CO4, Olathe, CO - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 73; injuries: serious; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review November 16, 2018; seat: left; restraint: 3-point; flight hours: 34,427 total, 3,729 in this make and model, 34,487 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Lowest ceiling: none - Temperature: 84 °F - Altimeter: 30.29 inHg - Observed at: 4 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 20190820019069A](https://openairdocs.org/incident/20190820019069A), Aug 20, 2019: Bell 47G-3B-1, Montrose, CO, Substantial damage. Pilot stated that as he came over the mesa and leveled off to start the application of pesticide, the helicopter yawed like a gust of wind hit the tail rotor.… ## Other investigations on N1170W (3) 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 DEN82FTM02](https://openairdocs.org/ntsb/DEN82FTM02), Nov 5, 1981: Soloy 47 (N1170W), Fruitland, UT, substantial damage - [NTSB SEA76FTI02](https://openairdocs.org/ntsb/SEA76FTI02), Jul 9, 1975: Bell 47G3B1 (N1170W), Elliston, MT, substantial damage - [NTSB DEN75AD022](https://openairdocs.org/ntsb/DEN75AD022), Oct 26, 1974: Bell 47G3B1 (N1170W), Vernal, UT, substantial damage ## Docket (5 files) The files NTSB released with the investigation on October 3, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100104. 2.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 966 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476450&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - E-mail from Rolls-Royce (item 2, .PDF, 75 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476451&FileExtension=.PDF&FileName=E-mail%20from%20Rolls-Royce-Master.PDF - E-mail from Olathe Spray Service (item 3, .PDF, 89 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476452&FileExtension=.PDF&FileName=E-mail%20from%20Olathe%20Spray%20Service-Master.PDF - Google Earth Map (item 4, .PDF, 1 photo, 477 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476453&FileExtension=.PDF&FileName=Google%20Earth%20Map-Master.PDF - Report Photos (item 5, .PDF, 2 photos, 600 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40476454&FileExtension=.PDF&FileName=Report%20Photos-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.