Hiller UH-12E accident near Lemoore, California, September 18, 1986
On September 18, 1986 at about 12:30 pm local time, a Hiller UH-12E (helicopter), registered N688SB, was substantially damaged in an accident near Lemoore, California (Lemore Nas airport). It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person had minor injuries. 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
- September 18, 1986 · about 12:30 pm local time
- Place
- Lemoore, California · Lemore Nas · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12E · all UH-12Es on the register
- Registration
- N688SB · no longer on the register · serial 1825
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
THE PLT REPTD THAT WHILE RETURNING TO THE LOADING AREA AFTER SPRAYING A FIELD, HE HEARD A LOUD POP EMANATING FROM THE ENGINE COMPARTMENT. SHORTLY THEREAFTER HE OBSERVED A FIRE IN THE ENGINE COMPARTMENT AND LOST FORWARD AND AFT CONTROL OF THE HELICOPTER. THE PLT IMMEDIATELY EXECUTED AN AUTOROTATION. THE HELICOPTER ROLLED OVER ONTO ITS SIDE ON TOUCH DOWN. THE POST-ACCIDENT INVESTIGATION ENGINE EXAMINATION DISCLOSED THAT THE NUMBER 3 CONNECTING ROD BOLTS FAILED. FURTHER EXAMINATION REVEALED THAT THE REMAINING CON ROD BOLTS TORQUE VALUES WERE ABT 50% LESS THAN THE REQUIRED VALUES.
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; rotorcraft: helicopter
- Flight time: 5,000 hours in all; 3,003 in this make and model; 150 in the last 90 days; 5,000 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Last inspection: 100-hour inspection, August 18, 1986; 51 hours since
- Maximum gross weight: 3,100 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming VO-540-C2A (piston); 0 hours total
- Fire in flight and on the ground
- Operator: West Farm Air
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: night, dark
- Visibility: 7 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.