Schweizer G-164B accident near Alturas, California, July 13, 2008
On July 13, 2008 at about 6:30 pm local time, a Schweizer G-164B, registered N3633B, was substantially damaged in an accident during maneuvering (low-alt flying) near Alturas, California. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A total loss of engine power due to fuel starvation, which resulted from a fuel system contamination and a clogged fuel filter. Contributing to the accident was the rough terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 13, 2008 · about 6:30 pm local time
- Place
- Alturas, California · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Schweizer G-164B
- Registration
- N3633B · no longer on the register · serial 775B
- 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 pilot reported that while maneuvering during an agricultural spray flight he felt the turbine engine shudder, and then it continued to operate normally. As a precaution, the pilot discontinued dispensing fertilizer and turned the heavily loaded airplane toward the departure airstrip. Suddenly, the engine shuddered again, and the pilot opted to immediately land in a nearby pasture. All engine power was lost as the airplane approached the field. The pilot made a forced landing on the rough ground and the airplane nosed over during rollout. The operator reported that inspection of the airplane's fuel filter revealed debris or some kind of organism that clogged the fuel filter. The same contaminating material was found in the airplane's fuel tanks. The operator also reported that the airplane had been refueled from a tank truck that was from out of the area.
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
What happened, in order
- Fuel contamination during maneuvering (low-alt flying) defining event
- Fuel starvation during maneuvering (low-alt flying)
- Loss of engine power (total) during maneuvering (low-alt flying)
- Off-field or emergency landing during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during landing
The NTSB's findings
- cause Aircraft › Aircraft systems › Fuel system › Fuel filter › strainer › Damaged/degraded
- factor Environmental issues › Physical environment › Terrain › Rough terrain › Contributed to outcome
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 22,357 hours in all; 1,596 in this make and model; 336 in the last 90 days; 153 in the last 30 days
- Medical certificate: Class 2
- Injury: no injuries
The aircraft
- Landing gear: fixed
- Engine: Airesearch TPE-331-2-201 (turboprop); 0 hours total
The flight
- Departed from: NONE Alturas CA
- Destination: NONE
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.
Other NTSB records under N3633B the same tail number, which may have belonged to a different aircraft at the time
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.