Aerospatiale SA-315 accident near Beckwourth, California, October 18, 1993
On October 18, 1993 at about 9:30 pm local time, a Aerospatiale SA-315 (helicopter), registered N49511, was substantially damaged in an accident near Beckwourth, California. It was a flight of an unrecorded kind under external-load helicopter rules (Part 133). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
was the worn collective servo causing a hydraulic lock and not allowing the pilot to lower the collective. This condition caused the main rotor blades rpm to decay.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 18, 1993 · about 9:30 pm local time
- Place
- Beckwourth, California · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale SA-315 · all SA-315s on the register
- Registration
- N49511 · no longer on the register · serial 2485
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT WAS CONDUCTING AN EXTERNAL HELICOPTER EXTERNAL LOAD LOGGING OPERATION. AFTER RAISING TWO LOGS, THE PILOT HEARD A LOUD 'THUNK' NOISE FOLLOWED BY AN UNCONTROLLED TURN TO THE RIGHT. THE PILOT WAS UNABLE TO MAINTAIN ADEQUATE ROTOR RPM BECAUSE HE COULD NOT LOWER THE COLLECTIVE. EXAMINATION OF THE COLLECTIVE SERVO REVEALED IT TO HAVE INTERNAL LEAKAGE WHICH CAUSED A HYDRAULIC LOCK IN THE SERVO. THE SERVO EXTENSION AND RETRACTION TIME EXCEEDED THE MANUFACTURER'S SPECIFICATIONS.
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: rotorcraft: helicopter
- Flight time: 9,000 hours in all; 1,800 in this make and model; 385 in the last 90 days; 125 in the last 30 days; 9,000 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 17,081 hours
- Last inspection: annual inspection, October 8, 1993; 33 hours since
- Maximum gross weight: 5,070 lb
- Seats: 5
- Landing gear: fixed
- Engine: Turbomeca ART III B (turboshaft); 0 hours total
The flight
- Departed from: O02 Nervino CA at 8:45 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: not reported
- Visibility: 25 statute miles
- Sky: overcast at 4,000 ft; not recorded
- Temperature: 61°F (16°C), dew point 0°F (-18°C)
- Altimeter: 29.00 inHg
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.