Mooney M20C accident near Englewood, Colorado, October 21, 1998
On October 21, 1998 at about 2:28 pm local time, a Mooney M20C, registered N6405U, was substantially damaged in an accident near Englewood, Colorado (Centennial 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
The undertorquing of the camshaft gear retaining bolts during engine overhaul by maintenance personnel. A factor was the unsuitable terrain for a forced landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 21, 1998 · about 2:28 pm local time
- Place
- Englewood, Colorado · Centennial Airport · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Mooney M20C · all M20Cs on the register
- Registration
- N6405U · no longer on the register · serial 2152
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During climb following departure, the engine lost power. The pilot reported the emergency to the tower and attempted to return to the airport. Determining that he would be unable to make it back, he made an emergency landing in a field one and a half miles southeast of the airport. Postaccident examination of the engine revealed that the camshaft gear retaining bolts connecting the camshaft gear to the camshaft had lost torque. As a result, the lobes failed to open their respective valves, creating discontinuity to the gear train. The tread on each of the four camshaft gear bolts exhibited shiny, worn patterns. According to a Textron Lycoming engineer, loss of camshaft retaining bolt torque is indicative of the bolts being improperly torqued during the engine overhaul. According to aircraft maintenance records, the engine was overhauled on March 15, 1985, and had accumulated 833 hours since overhaul.
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
- Flight time: 1,018 hours in all; 834 in this make and model; 43 in the last 90 days; 2 in the last 30 days; 996 as pilot in command
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 4,567 hours
- Last inspection: annual inspection, October 23, 1997; 112 hours since
- Maximum gross weight: 2,575 lb
- Seats: 4
- Landing gear: retractable
- Engine: Lycoming O-360-A1D (piston); 0 hours total
The flight
- Departed from: APA at 2:20 pm
- Destination: LHX La Junta CO
- Flight plan: none
- Runway 10, 4,903 ft by 62 ft
Weather at the time
- Light: daylight
- Wind: from 180° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 43°F (6°C), dew point 36°F (2°C)
- Altimeter: 30.00 inHg
- Observation at 2:45 pm from APA
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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.