Amateur-built SH-2-RG accident near Visalia, California, June 18, 1991
On June 18, 1991 at about 8:40 pm local time, a amateur-built SH-2-RG, registered N306AT, was substantially damaged in an accident near Visalia, California. It was a personal flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
TOTAL LOSS OF ENGINE POWER DUE TO THE FAILURE OF THE NUMBER 4 ENGINE EXHAUST VALVE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 18, 1991 · about 8:40 pm local time
- Place
- Visalia, California · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SH-2-RG
- Registration
- N306AT · no longer on the register · serial 306
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE CERTIFICATED PRIVATE PILOT/OWNER STATED THAT AN HOUR AND HALF INTO THE FLIGHT THE ENGINE STARTED TO RUN ROUGH AND LOST RPM. ALL INSTRUMENTS WERE IN THE GREEN. HE HEADED THE AIRCRAFT FOR A SUITABLE AIRPORT BUT THE ENGINE QUIT IN THE PATTERN. DUE TO WINDS HE WAS UNABLE TO MAKE THE RUNWAY. EXAMINATION OF THE ENGINE BY FAA INSPECTORS REVEALED THAT THE NUMBER 4 CYLINDER EXHAUST VALVE FAILED.
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: private
- Ratings: single-engine land
- Flight time: 1,330 hours in all; 370 in this make and model; 16 in the last 90 days; 4 in the last 30 days; 1,330 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded, January 2, 2000
- Maximum gross weight: 1,900 lb
- Seats: 2
- Landing gear: retractable
- Engine: Lycoming IO-360-A1B (piston); 0 hours total
The flight
- Departed from: L18 Fallbrook CA at 7:00 pm
- Destination: TVL Lake Tahoe CA
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 310° at 20 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| 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.