Cessna Aircraft CO LC41-550FG incident near Seal Beach, California, December 8, 2015
On December 8, 2015 at about 4:50 pm local time, a 2008 Cessna Aircraft CO LC41-550FG, registered N932AC, suffered minor damage in an incident during enroute (cruise) near Seal Beach, California. It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Improper maintenance performed on the left magneto which led to a loss of engine power. Contributing to the incident was the pilot's failure to check the magnetos in flight in compliance with manufacturers guidance regarding rough running engine. The pilot's decision to continue the flight after experiencing the rough running engine contributed to the necessity for a forced landing.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 8, 2015 · about 4:50 pm local time · cases in 2015
- Place
- Seal Beach, California · map
- Type
- Incident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna Aircraft CO LC41-550FG UNDESIGNAT, built 2008
- Registration
- N932AC · registry record · serial 411021
- Damage
- Minor damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot reported that the engine started "missing" [running rough] just after departure but he corrected the condition by leaning the mixture. While in cruise the engine started "missing" again but smoothed out after he turned towards a nearby airport, at which point the pilot decided to continue to his destination. When approximately 4 miles away from his destination the engine started to run rough, then quit. The pilot made a forced landing in to an open area. The pilot stated that he did not perform a magneto check at any time after the engine began running rough. Examination of the engine magnetos revealed that the left magneto gear washer and nylon washer had been installed in reverse order resulting in rapid bushing wear and excessive radial play of the distributor drive gear. This wear led to a migration of the internal timing in the left magneto that could have led to misfires or kickbacks during start that caused shock to the gear train and damaged one or more distributor gear teeth in the right magneto. Damage to one or more gear teeth led to a cascade of gear tooth fractures as the right magneto continued to operate. Eventually the right magneto drive gear decoupled from the engine resulting in cylinder 3 or 6 receiving a spark each time the points were opened during cam rotation, causing random ignition of the fuel-air mixture in those cylinders. The pilot's failure to follow the Pilot's Operating Handbook guidance to check the operation of the individual left and right magnetos once the engine began running rough likely missed the opportunity to regain engine power utilizing the functional left magneto.
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 (total) during enroute (cruise) defining event
- Off-field or emergency landing during enroute (cruise)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Ignition system › Magneto/distributor › Incorrect service/maintenance other cases naming the engine
- cause Aircraft › Aircraft power plant › Ignition system › Magneto/distributor › Damaged/degraded other cases naming the engine
- factor Personnel issues › Action/decision › Action › Incorrect action selection › Pilot
- factor Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- factor Personnel issues › Task performance › Use of equip/info › Use of checklist › Pilot
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: instrument airplane; instrument: airplane; rotorcraft: helicopter
- Flight time: 3,774 hours in all; 352 in this make and model; 30 in the last 90 days; 10 in the last 30 days; 3,840 as pilot in command
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Passenger
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 1,027 hours
- Last inspection: annual inspection, July 15, 2015; 85 hours since
- Maximum gross weight: 3,600 lb
- Seats: 4
- Landing gear: fixed
- Engine: Cont Motor TSIO-550-C (piston); 1,027 hours total
The flight
- Departed from: KMYG San Diego CA at 4:30 pm
- Destination: KLGB Long Beach CA
- Flight plan: VFR
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 63°F (17°C), dew point 43°F (6°C)
- Altimeter: 30.09 inHg
- Observation at 8:58 am from KLGB, 6 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
8 documents, released by the NTSB on May 3, 2018. 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 | Materials Laboratory Factual Report 16-063 | PDF, 4 pages | View Download |
| 2 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 10 pages | View Download |
| 3 | Pilot's Statement | PDF, 1 page | View Download |
| 4 | Maintenance Records | PDF, 6 pages | View Download |
| 5 | Australian Airworthiness Bulletin on Magnetos | PDF, 25 pages | View Download |
| 6 | Reports from Parties to the Investigation | PDF, 9 pages | View Download |
| 7 | Evidence Control Form | PDF, 1 page | View Download |
| 8 | Statement of Party Representatives to NTSB Investigation | PDF, 2 pages | 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
- N932AC on the register today · the tail number may have moved to another aircraft since
- Engine: Cont Motor TSIO-550-C 480 aircraft carry this series today · as the NTSB recorded it
- Long Beach (Daugherty Field) · bound for
- Accidents and incidents in California 9,080 since 1982 · 1,098 in the last ten years
- California 27,686 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/WPR16IA044.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.