Diamond DA 40 incident near San Carlos, California, September 13, 2008
On September 13, 2008 at about 5:00 pm local time, a Diamond DA 40, registered N419JS, suffered minor damage in an incident during enroute (climb to cruise) near San Carlos, California. It was a personal flight under general aviation rules (Part 91). 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
The improper assembly of the governor during manufacture.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 13, 2008 · about 5:00 pm local time
- Place
- San Carlos, California · map
- Type
- Incident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Diamond DA 40
- Registration
- N419JS · registry record · serial 40-439
- Damage
- Minor damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot departed on a local area flight when the engine had higher than normal RPMs. The pilot elected to return to the departure airport and his mechanic inspected the airplane. The mechanic discovered a blister in the engine casing and fragments of metal in the oil. The engine was then disassembled and a ball bearing from the propeller governor was located in the engine which had the potential of resulting in a catastrophic engine failure. Examination of the engine showed that the ball bearings from the governor were able to pass through the oil drain hole of the governor. Follow up examinations of the propeller governor showed that the governor bearing race and plunger were assembled with the bearing race set screw and plunger hole misaligned. When the bearing race set screw was torqued down, the set screw tip flattened against the harder plunger surface. During operation, the set screw/plunger race separated.
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
- Sys/Comp malf/fail (non-power) during enroute (climb to cruise) defining event
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Propeller system › Propeller governor › Failure
- cause Organizational issues › Development › Manufacture/production › Equipment manufacture › Manufacturer
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 732 hours in all; 640 in this make and model; 84 in the last 90 days; 26 in the last 30 days; 632 as pilot in command
- Last flight review: June 12, 2008
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 559 hours
- Last inspection: annual inspection, January 18, 2008; 559 hours since
- Maximum gross weight: 2,535 lb
- Seats: 4
- Landing gear: fixed
- Engine: Textron Lycoming IO-360M1A (piston); 0 hours total
The flight
- Departed from: SQL San Carlos CA at 4:40 pm
- Destination: SQL San Carlos CA
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 59°F (15°C), dew point 54°F (12°C)
- Altimeter: 29.93 inHg
- Observation at 4:47 pm from SQL, 2 miles away
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.
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.