Cessna 150M accident near Livermore, California, June 4, 1998
On June 4, 1998 at about 10:00 pm local time, a Cessna 150M, registered N704ZA, was substantially damaged in an accident near Livermore, California. It was an instructional 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
The missing nut/cotter pin on the throttle attachment assembly which resulted in the pilot's inability to control engine power, and the hidden obstruction (hole) in the landing area. A factor was the high vegetation.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 4, 1998 · about 10:00 pm local time
- Place
- Livermore, California · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 150M · all 150Ms on the register
- Registration
- N704ZA · no longer on the register · serial 15078992
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
After performing air work, the instructor and student were returning to base. The instructor noted a loss of rpm's from 2,300 to 1,100. He took over the aircraft controls from the student and attempted to correct the problem. The instructor noted that the rpm's remained constant at 1,100. He conducted the emergency checklist and informed the tower of the situation. The instructor then landed the aircraft in an open field of high grass during which the aircraft came to rest inverted after the nose wheel struck a hole. The aircraft was examined on-scene and it was noted that the bolt was in place, but that the nut and cotter pin were missing from the carburetor throttle attachment assembly. It was also noted that the aircraft had flown approximately 15 hours since the last annual inspection and maintenance had been performed.
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, flight instructor
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 1,700 hours in all; 600 in this make and model; 150 in the last 90 days; 40 in the last 30 days; 1,495 as pilot in command; 742 on instruments
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 6,500 hours
- Last inspection: annual inspection, May 8, 1998; 15 hours since
- Maximum gross weight: 1,600 lb
- Seats: 2
- Landing gear: fixed
- Engine: Continental O-200 (piston); 0 hours total
The flight
- Departed from: HWD at 8:10 pm
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 260° at 13 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 3,500 ft; clear
- Temperature: 64°F (18°C), dew point 52°F (11°C)
- Altimeter: 30.00 inHg
- Observation at 8:53 pm from LVK, 3 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.