Bell 47G4 accident near Merced, California, October 11, 1990
On October 11, 1990 at about 5:58 pm local time, a Bell 47G4 (helicopter), registered N477JM, was destroyed in an accident near Merced, California. It was a business flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
LOSS OF ENGINE POWER FOR AN UNDETERMINED REASON.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 11, 1990 · about 5:58 pm local time
- Place
- Merced, California · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G4 · all 47G4s on the register
- Registration
- N477JM · registry record · serial 3139
- Damage
- Destroyed
- Flight
- Business flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
AFTER WASHING THE HELICOPTER THE PILOT TOOK-OFF ON A BUSINESS FLIGHT OVER HIS RANCH. A GROUND WITNESS HEARD THE ENGINE STOP AND OBSERVED THE HELICOPTER ENTER AN AUTOROTATIVE DESCENT. THE HELICOPTER LANDED HARD AND BURST INTO FLAMES. THE WITNESS ESTIMATED THE HELICOPTERS ALTITUDE WAS ABOUT 50 FEET ABOVE THE GROUND WHEN HE FIRST OBSERVED IT. POST ACCIDENT EXAM OF THE HELICOPTER AND ENGINE REVEALED NO EVIDENCE OF A PREIMPACT MECHANICAL MALFUNCTION OR FAILURE.
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: commercial pilot
- Ratings: single-engine land; instrument: airplane; rotorcraft: helicopter
- Flight time: 15,000 hours in all
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded; 0 hours since
- Maximum gross weight: 2,950 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming VO-540-B1B3 (piston); 0 hours total
- Fire on the ground
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: dawn
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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.
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.