Aerospatiale SA 316B accident near Bridgeport, California, November 28, 1991
On November 28, 1991 at about 7:21 am local time, a Aerospatiale SA 316B (helicopter), registered N146RM, was destroyed in an accident near Bridgeport, California. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). 4 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
FAILURE OF THE HELICOPTER'S TAIL ROTOR DRIVE SHAFT AND DRIVE SHAFT BEARING DUE TO UNDETERMINED REASON(S).
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 28, 1991 · about 7:21 am local time
- Place
- Bridgeport, California · map
- Type
- Accident
- Injuries
- 4 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale SA 316B
- Registration
- N146RM · registry record · serial 1614
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
THE AEROMEDICAL EVACUATION (EMS-MEDEVAC) FLT WAS MADE AT NGT OVR MTN TRRN. THE PLT INTERRUPTED HIS NORMAL PSN RPRT & BROADCAST 'MAYDAY' 3 TIMES, GIVING HIS PSN TO A COMPANY DISPATCHER. HE DID NOT STATE THE NATURE OF THE EMERGENCY. NO FURTHER COMM WAS RECORDED. WITNESSES IN A SOUTHBOUND AUTO SAW THE HELICOPTER FLYING TOWARD THEM FROM THE SOUTH. THEY STATED THE HELICOPTER'S FUSELAGE STARTED ROTATING COUNTER-CLOCKWISE. IT THEN VEERED TO THE WEST, WENT OUT OF SIGHT, AND CRASHED. ALL MAJ COMPONENTS, EXCEPT ABOUT 33 INCHES OF THE TAIL ROTOR DRIVE SHAFT & ITS #5 BRG, WERE LOCATED. THE TAIL BOOM WAS FOUND IN 3 SECTIONS. ROTATIONAL & LONGITUDINAL SCORING DAMAGE WAS NOTED ON THE TAIL BOOM IN THE VCNTY OF THE #3 & #5 BRG SUPPORTS. A LAB RPRT STATED THAT THE ROTATIONAL DMG OCCURRED BEFORE THE GROSS DEFORMATION OF THE TAIL BOOM & SUBSEQUENT IN-FLT BREAKUP 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
Pilot
- Certificate: airline transport pilot
- Ratings: single-engine land; instrument: helicopter; rotorcraft: helicopter
- Flight time: 11,095 hours in all; 2,163 in this make and model; 76 in the last 90 days; 28 in the last 30 days; 11,095 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 7,525 hours
- Last inspection: approved inspection programme, October 25, 1991; 53 hours since
- Maximum gross weight: 4,850 lb
- Seats: 4
- Landing gear: fixed
- Engine: Turbomeca ARTOUSTE IIIB (turboshaft); 0 hours total
The flight
- Departed from: Q18 Bridgeport CA at 7:05 am
- Destination: NONE Reno NV
- Runway 0
Weather at the time
- Light: night, dark
- Visibility: 3 statute miles
- Sky: not recorded; not recorded
- Temperature: 12°F (-11°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 3 | |||
| Passengers | 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.