Bell 47G-4 accident near Los Banos, California, August 21, 2011
On August 21, 2011 at about 1:55 pm local time, a Bell 47G-4 (helicopter), registered N948DS, was substantially damaged in an accident during maneuvering (hover) near Los Banos, California (Los Banos airport). It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's failure to maintain clearance from the power poles while maneuvering during low-altitude operations.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 21, 2011 · about 1:55 pm local time · cases in 2011
- Place
- Los Banos, California · Los Banos · cases near this airport · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G-4 · all 47G-4s on the register
- Registration
- N948DS · no longer on the register · serial 3140
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The pilot was performing an agricultural application flight in the helicopter over a cantaloupe field. During the final pass along the field border, he observed bee boxes adjacent to power poles, and he shut off the spray applicator. After passing the boxes, he turned the spray applicator back on; his next recollection was of lying upside down in the field. Examination of the helicopter at the accident site revealed that the main rotor blades struck a set of wooden power poles at the 20-foot-level. The helicopter sustained substantial damage to the main rotor blades and fuselage structure. The pilot reported that he had flown an application flight over the same field a week prior, and was aware of the location of the power poles. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation.
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
- Controlled flight into terrain or object (CFIT) during maneuvering (hover) defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Task monitoring/vigilance › Pilot
- cause Environmental issues › Physical environment › Object/animal/substance › Pole › Response/compensation
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 1,643 hours in all; 143 in this make and model; 243 in the last 90 days; 133 in the last 30 days; 1,583 as pilot in command; 650 on instruments
- Last flight review: August 10, 2010
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 8,954 hours
- Last inspection: annual inspection, June 1, 2011; 81 hours since
- Maximum gross weight: 2,950 lb
- Seats: 3
- Landing gear: fixed
- Engine: Allison 250-C20B (turboshaft); 0 hours total
- Operator: Double Springs LLC
The flight
- Departed from: KLSN Los Banos CA at 12:00 pm
- Destination: KLSN Los Banos CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 310° at 3 knots
- Visibility: 9 statute miles
- Sky: clear
- Temperature: 57°F (14°C), dew point 54°F (12°C)
- Altimeter: 29.89 inHg
- Observation at 11:53 am from KMCE, 21 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
3 documents, released by the NTSB on September 15, 2011. 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, 7 pages | View Download |
| 2 | Photo 1: Helicopter and Power Pole | PDF, 1 page | View Download |
| 3 | Photo 2: Helicopter | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N948DS: not on the register today · the record of its deregistration
- Bell 47 478 registered today · the model family and its accident history
- Bell 3,079 aircraft on the register
- Engine: Allison 250-C20B 113 aircraft carry this series today · as the NTSB recorded it
- Los Banos Municipal · nearest airport
- Accidents and incidents in California 9,080 since 1982 · 1,098 in the last ten years
- California 27,686 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/WPR11CA398.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.