Mooney M20B accident near St. George, Utah, March 18, 2007
On March 18, 2007, a Mooney M20B, registered N74503, was substantially damaged in an accident near St. George, Utah (St. George airport). 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
Oil contamination of the right magneto. Factors were the airplane owner's failure to comply with manufacturer's service bulletins and overhaul porcedures.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 18, 2007
- Place
- St. George, Utah · St. George · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mooney M20B · all M20Bs on the register
- Registration
- N74503 · no longer on the register · serial 1814
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Ten minutes after takeoff the airplane's engine started running rough, and the airplane collided with terrain during a forced landing into an open area. The pilot leveled the airplane at 6,500 feet for cruise and the engine started running rough and backfiring. The engine would run sporadically rough then smooth out. The pilot executed emergency procedures, switched fuel tanks, and switched on the boost pump, but there was no change in the engine's rough-running condition. He decided to return to the airport, and configured the airplane for best glide. He setup for a 2-mile final to runway 34. The pilot determined that he was not going to make the runway, and force landed the airplane in a clear area by a river bed. An examination of the engine determined that the right magneto contained engine oil. The seal between the engine accessory drive and the magneto was hard, loose fitting, and covered with engine oil. Examination of the engine maintenance logbook revealed that the engine had been manufactured new on February 8, 1979, and installed on the airplane April 13, 1979. A 9-year gap where no maintenance was recorded on the engine occurred between October 1992 (engine total time of 1302.9 hours) and July 2002 (engine total time of 1322.39 hours). A 100-hour inspection was recorded as being completed on July 2, 2002. The most recent 100-hour inspection was performed on June 22, 2006, at 1,439.1 hours total time. There is no record of an engine or magneto overhaul. Lycoming Service Instruction No. 1009AS states that engines that do not accumulate the hourly period of time between overhauls specified (2,000 hours for the O-360-A1D) are recommended to be overhauled in the twelfth year. Teledyne Continental Ignition systems Service Bulletin, SB643B, for all TCM and Bendix magnetos states that the magnetos must be overhauled or replaced at the expiration of 5 years since the date of original manufacture or last overhaul, or 4 years since the date the magneto was placed in service, which ever occurs first with out regard to accumulated operating hours.
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: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 462 hours in all; 325 in this make and model; 68 in the last 90 days; 42 in the last 30 days; 419 as pilot in command
- Medical certificate: Class 3
- Injury: no injuries
The aircraft
- Airframe total time: 3,958.5 hours
- Last inspection: annual inspection, June 1, 2006
- Maximum gross weight: 2,450 lb
- Seats: 4
- Landing gear: retractable
- Engine: Lycoming O-360-A1D (piston); 0 hours total
The flight
- Departed from: KSGU St. George UT at 11:45 pm
- Destination: KU02 Blackfoot ID
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 260° at 14 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 82°F (28°C), dew point 21°F (-6°C)
- Altimeter: 29.90 inHg
- Observation at 1:35 am from KSGU, 2 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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.