Bell 47G-4A accident near Rochester, Minnesota, July 24, 2010
On July 24, 2010 at about 7:00 pm local time, a 1967 Bell 47G-4A (helicopter), registered N124SH, was substantially damaged in an accident during maneuvering (low-alt flying) near Rochester, Minnesota. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was killed. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The total loss of engine power due to a high-cycle fatigue fracture of a first-stage compressor blade. The reason for the fracture could not be determined during postaccident examination.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 24, 2010 · about 7:00 pm local time
- Place
- Rochester, Minnesota · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G-4A, built 1967 · all 47G-4As on the register
- Registration
- N124SH · registry record · serial 7599
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
A witness reported that the agricultural helicopter was refueled and that the hopper was loaded with chemical before departure. He reported that he saw the helicopter depart, that the engine sounded normal, and that the helicopter's departure and flightpath appeared normal. He then saw a "brown puff of smoke" come from the helicopter, and it subsequently descended and impacted a hill. A postaccident engine examination revealed that the compressor rotor assembly had failed. The metallurgical examination of the compressor rotor assembly revealed that a single first-stage compressor blade had fractured in high-cycle fatigue. The microstructure, hardness, and chemistry of the first-stage compressor wheel conformed to the requirements of the engineering drawing. No evidence of corrosion was found near the fracture origin. The engine was installed on the helicopter during the last annual maintenance inspection conducted 3 days before the accident. Evidence indicated that the engine was installed properly. The reason for the fracture could not be determined.
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 engine power (total) during maneuvering (low-alt flying) defining event
- Autorotation Collision with terrain or object (not controlled flight into terrain)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Compressor section › Fatigue/wear/corrosion
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; rotorcraft: helicopter
- Flight time: 16,000 hours in all; 4,500 in this make and model
- Last flight review: April 20, 2010
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 15,020 hours
- Last inspection: annual inspection, July 15, 2010; 5.2 hours since
- Maximum gross weight: 2,950 lb
- Seats: 3
- Landing gear: fixed
- Engine: Allison A250-C10D (turboshaft); 3,782 hours total
- Operator: Scotts Helicopter Services INC
The flight
- Departed from: Local Airstrip IL at 6:26 pm
- Destination: Local Airstrip IL
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 210° at 11 knots, gusting 15
- Visibility: 10 statute miles
- Sky: broken clouds at 25,000 ft; scat
- Temperature: 91°F (33°C), dew point 72°F (22°C)
- Altimeter: 30.05 inHg
- Observation at 6:53 pm from RST, 15 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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number CEN10LA431.