Mcdonnell Douglas 369E accident near Santa Rosa, California, December 29, 1989
On December 29, 1989 at about 7:30 pm local time, a Mcdonnell Douglas 369E (helicopter), registered N1604L, was destroyed in an accident near Santa Rosa, California (Sonoma County airport). It was a business flight under general aviation rules (Part 91). 1 person was killed, 1 person was seriously injured and 3 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE PILOT'S IMPROPER PREFLIGHT PLANNING/DECISION WHICH RESULTED IN THE LOSS OF TAIL ROTOR EFFECTIVENESS. CONTRIBUTING TO THE ACCIDENT WAS THE PILOT ALLOWING THE MAXIMUM GROSS WEIGHT OF THE AIRCRAFT TO BE EXCEEDED, AND THE TAILWIND.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 29, 1989 · about 7:30 pm local time
- Place
- Santa Rosa, California · Sonoma County · map
- Type
- Accident
- Injuries
- 1 person was killed, 1 person was seriously injured and 3 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Mcdonnell Douglas 369E
- Registration
- N1604L · no longer on the register · serial 0266E
- Damage
- Destroyed
- Flight
- Business flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT EXECUTED AN IMMEDIATE LEFT DOWNWIND CLIMBING TURN WHEN HE DEPARTED THE HELIPAD AND EXPERIENCED A LOSS OF TAIL ROTOR EFFECTIVENESS. BEFORE DEPARTING, THE PILOT FAILED TO ACCOUNT FOR THE DOWNWIND TURN AND THE HELICOPTER'S EXCEEDING THE MAXIMUM GROSS WEIGHT. THE POST ACCIDENT INVESTIGATION DISCLOSED THE LATERAL TRIM MOTOR EXCEEDED ITS PHYSICAL EXTENSION LIMITS WHICH INDICATES THAT THE TRIM MOTOR WAS OPERATING DURING THE IMPACT SEQUENCE WHEN ITS AIRFRAME ATTACHMENT POINT WAS BROKEN.
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, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane; rotorcraft: helicopter
- Flight time: 4,123 hours in all; 57 in this make and model; 106 in the last 90 days; 27 in the last 30 days; 3,705 as pilot in command; 1,023 on instruments
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 367 hours
- Last inspection: 100-hour inspection, November 21, 1989
- Maximum gross weight: 3,000 lb
- Seats: 5
- Landing gear: fixed
- Engine: Allison 250-C20 (turboshaft); 0 hours total
- Operator: Interwest, INC.
The flight
- Departed from: STS at 7:30 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 310° at 5 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 59°F (15°C), dew point 37°F (3°C)
- Altimeter: 30.00 inHg
- Observation at 7:32 pm
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 | 1 | 2 |
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.