Bell 47G-4A accident near Mayville, Wisconsin, July 24, 2008
On July 24, 2008 at about 11:52 am local time, a Bell 47G-4A (helicopter), registered N24HM, suffered minor damage in an accident during standing (engine(s) operating) near Mayville, Wisconsin. 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).
The NTSB's probable cause their words, unchanged
The pilot's failure to maintain clearance with the rotating rotor blades after he exited the helicopter after landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 24, 2008 · about 11:52 am local time
- Place
- Mayville, Wisconsin · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G-4A · all 47G-4As on the register
- Registration
- N24HM · no longer on the register · serial 7688
- Damage
- Minor damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
A witness heard the engine running rough when the agricultural application helicopter took off, adjacent to the field that was going to be sprayed. The pilot then landed the helicopter in the field which had tall vegetation and uneven terrain. The left skid separated during landing resulting in the helicopter resting left side low. The pilot then exited and walked around the helicopter when he was struck by the rotating main rotor blades and was fatally injuried. Examination of the engine revealed an exhaust valve that displayed excessive wear which would result in the engine running rough due to the valve sticking. Logbook records show that the engine and parts manufacturer approval (PMA) manufacturer's recommended maintenance had not been performed.
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
- AC/prop/rotor contact w person during standing (engine(s) operating) defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › (general) › Pilot
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 24,000 hours in all; 16,000 in this make and model; 56 in the last 90 days; 56 in the last 30 days; 24,000 as pilot in command
- Last flight review: January 21, 2008
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 10,775 hours
- Last inspection: annual inspection, November 1, 2007
- Maximum gross weight: 3,200 lb
- Seats: 3
- Landing gear: fixed
- Engine: Textron Lycoming VO-540-B1B3 (piston); 0 hours total
The flight
- Departed from: Mayville WI at 11:52 am
- Destination: Mayville WI
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 180° at 2 knots
- Visibility: 10 statute miles
- Sky: overcast at 4,000 ft; ovct at 4,000 ft
- Temperature: 61°F (16°C), dew point 0°F (-18°C)
- Altimeter: 30.05 inHg
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 N24HM 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.