Amateur-built THORP T-18 accident near San Diego, California, January 25, 1997
On January 25, 1997 at about 6:38 pm local time, a amateur-built THORP T-18, registered N40918, was destroyed in an accident near San Diego, California (San Diego Brown Field). It was an instructional flight under general aviation rules (Part 91). 2 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Installation by the pilot/owner of an unairworthy check valve in the fuel system of the amateur built aircraft, which resulted in inadequate fuel flow to the engine and subsequent engine failure. A factor in the accident was the owner's operation of the aircraft with known deficiencies.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 25, 1997 · about 6:38 pm local time
- Place
- San Diego, California · San Diego Brown Field · map
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built THORP T-18
- Registration
- N40918 · no longer on the register · serial 1
- Damage
- Destroyed
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
According to pilots who were familiar with the experimental aircraft, the engine had a history of power loss events dating back several months prior to the accident flight. On the day of the accident, the CFI and the dual student/aircraft owner had completed two touch-and-go landings and were on crosswind leg when the engine abruptly quit. A crash and postcrash fire resulted from the ensuing forced landing. A postcrash investigation revealed that a check valve was present in the engine fuel system to provide fuel under pressure to the carburetor when the electric boost pump was operating. The check valve was disassembled and was found to have no internal components. This permitted the fuel to circulate back to the fuel pump inlet and interfered with fuel flow to the carburetor.
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: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 3,441 hours in all; 3,020 as pilot in command
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: annual inspection, April 3, 1996
- Landing gear: fixed
- Engine: Lycoming O-320-H2AD (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: SDM at 6:36 pm
- Flight plan: none
- Runway 26R, 7,999 ft by 200 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 8 statute miles
- Sky: broken clouds at 2,500 ft; scat at 2,000 ft
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
- Observation at 6:51 pm from SDM, 1 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.