Cessna 120 accident near Livermore, California, August 21, 2019
On August 21, 2019 at about 6:50 pm local time, a 1947 Cessna 120, registered N4237N, was substantially damaged in an accident during takeoff near Livermore, California (Livermore Municipal Airport). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A partial loss of engine power due to fouled spark plugs in the No. 4 cylinder. Contributing to the accident was the pilot’s exceedance of the airplane’s critical angle of attack and a subsequent loss of control during the initial climb.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 21, 2019 · about 6:50 pm local time · cases in 2019
- Place
- Livermore, California · Livermore Municipal Airport · cases near this airport · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 120, built 1947 · all 120s on the register
- Registration
- N4237N · no longer on the register · serial 13708
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The accident flight was the first flight following the airplane’s annual inspection. The pilot reported that, during the takeoff roll, the airplane took longer than expected to accelerate, and after becoming airborne, did not seem to be producing full power. Witnesses stated that the airplane made a sharp left turn about 100 feet above the ground and the left wing impacted the ground; the airplane cartwheeled before coming to rest, resulting in substantial damage. A postaccident examination revealed that the upper and lower spark plugs from the No. 4 cylinder and the lower spark plug from the No. 3 cylinder exhibited oil and soot bridging the gap between the electrodes. All other spark plugs exhibited black soot build-up on the electrodes and insulators. The reason for the fouled spark plugs was not determined based on the examination. The mechanic who completed the annual inspection reported that he cleaned, gapped, and functionally tested all of the spark plugs. After the inspection, he conducted an engine run-up and found that one of the plugs had become fouled. He cleaned the plugs a second time and reinstalled them using new gaskets. He ran the engine up a second time, and it ran smoothly. Based on the condition of the No. 4 cylinder spark plugs, it is likely that the engine was not producing nominal power and that its takeoff and climb performance was degraded. The witness observations of a steep left turn and descent to impact is consistent with an aerodynamic stall due to the pilot exceeding the airplane’s critical angle of attack during the initial climb.
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
- Loss of engine power (partial) during takeoff defining event
- Collision during takeoff/land during takeoff
- Powerplant sys/comp malf/fail during takeoff
The NTSB's findings
- Aircraft › Aircraft power plant › Ignition system › Spark plugs/igniters › Damaged/degraded other cases naming the engine
- Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Angle of attack › Capability exceeded
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 1 hours in all; 1 in this make and model
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: unk
- Injury: serious injuries
The aircraft
- Last inspection: annual inspection, August 19, 2019; 0 hours since
- Maximum gross weight: 1,451 lb
- Seats: 2
- Landing gear: fixed
- Engine: Continental O-200-A (piston); 475 hours total
The flight
- Departed from: LVK Livermore CA at 6:50 pm
- Flight plan: none
- Runway 25L, 2,699 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: at 5 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 55°F (13°C)
- Altimeter: 29.94 inHg
- Observation at 6:53 pm from LVK
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Photographs from the investigation 4 pictures from the NTSB's docket, as the NTSB released them
The NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
7 documents, released by the NTSB on March 16, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot Statement | PDF, 2 pages | View Download |
| 2 | Record of Conversation - Witness | PDF, 1 page | View Download |
| 3 | Record of Memorandum - FAA Engine Examination | PDF, 7 pages | View Download |
| 4 | Mechanic Statement | PDF, 1 page | View Download |
| 5 | Record of Memorandum - NTSB Pilot/operator 6120.1 Form | PDF, 1 page | View Download |
| 6 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | View Download |
| 7 | On Scene Photos - Courtesy of Local Law Enforcement | PDF, 4 pages · our copy | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N4237N: not on the register today · the record of its deregistration
- Cessna 120 660 registered today · the model family and its accident history
- Cessna 72,677 aircraft on the register
- Engine: Continental O-200-A 297 aircraft carry this series today · as the NTSB recorded it
- Livermore Municipal · nearest airport
- Accidents and incidents in California 9,080 since 1982 · 1,096 in the last ten years
- California 28,158 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/WPR19LA233.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.