Bell 47G accident near Montrose, Colorado, August 20, 2019
On August 20, 2019 at about 4:30 pm local time, a 1965 Bell 47G (helicopter), registered N1170W, was substantially damaged in an accident during maneuvering (low-alt flying) near Montrose, Colorado. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power due to fuel starvation, which resulted from attitude-induced unporting of the fuel.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 20, 2019 · about 4:30 pm local time
- Place
- Montrose, Colorado · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G 3B-1, built 1965 · all 47Gs on the register
- Registration
- N1170W · no longer on the register · serial 2944
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Fuel starvation during maneuvering (low-alt flying) defining event
- Off-field or emergency landing during emergency descent
The NTSB's findings
- factor Aircraft › Fluids/misc hardware › Fluids › Fuel › Fluid level
- factor Aircraft › Fluids/misc hardware › Fluids › Fuel › Related operating info
- factor Aircraft › Aircraft systems › Fuel system › Fuel distribution › Design
- factor Aircraft › Aircraft systems › Fuel system › Fuel distribution › Capability exceeded
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane; rotorcraft: helicopter
- Flight time: 34,427 hours in all; 3,729 in this make and model; 34,487 as pilot in command
- Last flight review: November 16, 2018
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 13,693 hours
- Last inspection: 100-hour inspection, June 24, 2019
- Maximum gross weight: 2,950 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rolls-Royce 250-C20B (turboshaft); 8,992 hours total
- Operator: Olathe Spray Service, Inc.
The flight
- Departed from: 1CO4 Olathe CO at 4:00 pm
- Destination: 1CO4 Olathe CO
- Flight plan: none
Weather at the time
- Light: daylight
- Sky: clear
- Temperature: 84°F (29°C), dew point 0°F (-18°C)
- Altimeter: 30.29 inHg
- Observation at 5:00 pm, 4 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on October 3, 2019. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | E-mail from Rolls-royce | PDF, 1 page | View Download |
| 3 | E-mail from Olathe Spray Service | PDF, 1 page | View Download |
| 4 | Google Earth Map | PDF, 1 page | View Download |
| 5 | Report Photos | PDF, 2 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.