Bell 47G-3B-1 accident near Vinton, Iowa, August 6, 2013
On August 6, 2013 at about 3:30 pm local time, a 1966 Bell 47G-3B-1 (helicopter), registered N83702, was substantially damaged in an accident during takeoff near Vinton, Iowa. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's operation of the helicopter at high gross weight and high density altitude while still in ground effect, which reduced the efficiency of the rotor system and the amount of lift produced, which resulted in a collision with terrain. Contributing to the accident was the pilot's decision to continue the flight after the first indication of reduced performance.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 6, 2013 · about 3:30 pm local time
- Place
- Vinton, Iowa · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G-3B-1, built 1966 · all 47G-3B-1s on the register
- Registration
- N83702 · no longer on the register · serial 66-8093
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
After reloading the helicopter with agricultural spray product, the pilot flew the helicopter off of the loading truck bed for the aerial application flight. Shortly after takeoff, while operating the helicopter at an altitude of about 10 feet above the ground, the pilot noted a decrease in rotor rpm and made a precautionary landing in tall grass. When he noted no anomalies after the landing, the pilot decided to continue the flight. He took off in the helicopter again and flew for about 100 yards before he again noted a decrease in rotor rpm. The helicopter descended and struck the ground with the tail low, which resulted in substantial damage to the tail rotor and tailboom. An examination of the airframe and engine did not reveal any mechanical malfunctions or failures that would have precluded normal operation. The helicopter was operating above tall grass and crops while still in ground effect, which likely reduced the efficiency of the rotor system and decreased the amount of lift produced as compared to operating over bare ground. In addition, the helicopter was loaded to within 16 pounds of its maximum gross weight and was operating at a density altitude of about 2,800 feet, which likely also contributed to the decreased performance of the helicopter.
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
- Loss of control in flight during takeoff defining event
- Collision with terrain or object (not controlled flight into terrain) during takeoff
The NTSB's findings
- cause Aircraft › Aircraft oper/perf/capability › (general) › (general) › Not attained/maintained
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Pilot
- factor Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › (general) › Capability exceeded
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 1,347 hours in all; 210 in this make and model; 41 in the last 90 days; 41 in the last 30 days; 548 as pilot in command; 31 on instruments
- Last flight review: April 16, 2013
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 77 hours
- Last inspection: annual inspection; 41 hours since
- Maximum gross weight: 2,850 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming TVO-435-B1A (piston); 77 hours total
- Operator: Speas Aviation Inc
The flight
- Departed from: Vinton IA at 3:30 pm
- Destination: Vinton IA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 230° at 3 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 70°F (21°C)
- Altimeter: 29.88 inHg
- Observation at 3:55 pm from KVTI, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N83702 the same tail number, which may have belonged to a different aircraft at the time
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.