Bell 47-G2A accident near Dousman, Wisconsin, April 30, 1992
On April 30, 1992 at about 3:45 pm local time, a Bell 47-G2A (helicopter), registered N52HB, was substantially damaged in an accident near Dousman, Wisconsin. It was an instructional flight under general aviation rules (Part 91). 1 person was seriously injured and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE IN-FLIGHT LOSS OF THE SWASH PLATE DRIVE LINK BOLT WHICH ALLOWED THE SWASH PLATE DRIVE ASSEMBLY TO DISCONNECT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 30, 1992 · about 3:45 pm local time
- Place
- Dousman, Wisconsin · map
- Type
- Accident
- Injuries
- 1 person was seriously injured and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47-G2A · all 47-G2As on the register
- Registration
- N52HB · no longer on the register · serial 3244
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE FLIGHT INSTRUCTOR (CFI) REPORTED THE DUAL INSTRUCTIONAL FLIGHT PROCEEDED WITHOUT INCIDENT FOR THE FIRST HOUR. WHILE RETURNING TO THE AIRPORT IN CRUISE FLIGHT, A SUDDEN AND VERY VIOLENT VIBRATION OCCURRED. THE CFI TOOK THE FLIGHT CONTROLS AND BEGAN AN AUTOROTATION TO AN OFF-AIRPORT SITE, STRIKING TREES DURING THE DESCENT. INSPECTION OF THE ROTOR HEAD DISCOVERED A MISSING SWASH PLATE DRIVE LINK BOLT, WHICH ALLOWED THE DRIVE LINK TO DISCONNECT. BOTH THE CFI AND STUDENT RECALLED CHECKING THE BOLT AND ASSOCIATED NUT AND COTTER PIN PRIOR TO THE FLIGHT AND FOUND NO ANOMALIES. THE BOLT WAS NEVER LOCATED.
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
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 17,000 hours in all; 5,000 in this make and model
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 8,600 hours
- Last inspection: 100-hour inspection, February 7, 1992; 94 hours since
- Maximum gross weight: 2,850 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming VO-435-A1F (piston); 0 hours total
- Operator: Mc Dermott Enterprises, INC.
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 050° at 10 knots
- Visibility: 8 statute miles
- Sky: scat at 6,500 ft
- Temperature: 55°F (13°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
- Observation at 3:50 pm from UES, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | 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.
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.