Amateur-built BV-107-II accident near Shaver Lake, California, August 20, 1983
On August 20, 1983 at about 5:05 pm local time, a amateur-built BV-107-II (helicopter), registered N190CH, was destroyed in an accident near Shaver Lake, California. It was a flight of an unrecorded kind under external-load helicopter rules (Part 133). 2 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 20, 1983 · about 5:05 pm local time
- Place
- Shaver Lake, California · map
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built BV-107-II
- Registration
- N190CH · registry record · serial 2002
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
THE ONLY WITNESS, THE HOOKER, WHO GETS LOGS READY FOR TRANSPORT BY THE HELICOPTER, STATED THAT HE HEARD NOISES AND THE ROTOR BLADES BEGAN COMING APART AS THE ACFT STARTED DOWNHILL WITH A LOG. EXAMINATION OF THE WRECKAGE REVEALED THAT #3 SYCHRONIZING SHAFT (BOEING P/N 10703141-13) HAD FAILED A FATIGUE CRACK ORIGINATING AT A RIVET HOLE. THE TOTAL TIME ON THE SHAFT WAS 17492 HOURS WITH 435 HOURS SINCE OVERHAUL. THE QUALITY OF THE SURFACE FINISH ON THE RIVET HOLES WAS CONSIDERED UNSATISFACTORY IN A POST ACCIDENT LABORATORY EVALUATION. AS A INTERIM MEASURE BOEING VERTOL ARBITRAILY IMPOSED A LIFE OF 8750 HOURS ON ALL SYNCHRONIZING SHAFTS OF THIS TYPE. THIS WAS BASED ON THE LIFE OF THIS FAILED PART. A PROGRAM IS ALSO BEING DEVELOPED TO DO A FLT STRAIN SURVEY ON A BV-107 FOR LOGGING OPERATIONS. THE HOOKER STATED THAT THE LOG BEING LIFTED BY THE ACCIDENT ACFT WEIGHED BETWEEN 8000 AND 9000 POUNDS.
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, commercial pilot
- Ratings: single-engine land; instrument: helicopter; rotorcraft: helicopter
- Flight time: 2,422 in this make and model
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 2,392 hours
- Last inspection: approved inspection programme, August 18, 1983; 8 hours since
- Maximum gross weight: 13,500 lb
- Seats: 2
- Landing gear: fixed
- Engine: Ge CT 581401A (turboshaft); 0 hours total
The flight
- Departed from: Shaver Lake CA at 1:30 pm
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 250° at 15 knots
- Visibility: 50 statute miles
- Sky: not recorded; scat
- Temperature: 61°F (16°C), dew point 0°F (-18°C)
- Observation at 4:50 pm from FAT, 35 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 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.