Piper PA-46-310P incident near Aspen, Colorado, December 26, 2007
On December 26, 2007 at about 5:00 pm local time, a Piper PA-46-310P, registered N47BC, suffered minor damage in an incident near Aspen, Colorado (Aspen/Pitkin County airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 4 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the crankshaft due to fatigue. The fatigue crack initiation was not determined.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 26, 2007 · about 5:00 pm local time
- Place
- Aspen, Colorado · Aspen/Pitkin County · map
- Type
- Incident
- Injuries
- No one was hurt; 4 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-46-310P · all PA-46-310Ps on the register
- Registration
- N47BC · registry record · serial 4608129
- Damage
- Minor damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During initial climb at 16,000 feet, the pilot noticed oil droplets forming on his windscreen. On seeing the oil, he contacted air traffic control, declared an emergency, and began a standard rate, 180-degree turn, back to the airport. As he completed the turn, he heard a "boom," felt a shutter, and then the windscreen was covered with oil. The pilot said he may have noted a pitch up with the bang, but he immediately got on the best glide speed, 90 knots, and began retracing his ground track via the global positioning system (GPS) back to the airport. The airplane landed uneventfully back to the airport. An examination of the airplane showed minor damage to the front of the cowling, and the engine showed the crankshaft fractured aft of the flange. The propeller and spinner, and the forward part of the crankshaft were missing. Several months after the incident, the separated propeller assembly and crankshaft were located. Examination of the engine revealed the crankshaft was fractured through, aft of the propeller flange. The fracture of the crankshaft was caused by a fatigue crack that stemmed from the aft relief radius of the propeller flange. The surface of the aft radius contained no evidence of mechanical damage and the fatigue crack emanated from multiple origins over a wide area, indicating that a great amount of stress was necessary to initiate the fatigue crack. The reason for the crack initiation could not be determined. The fatigue crack origin area was located in the relief radius in line with the axis of the propeller blades, consistent with forward and aft bending stresses imposed by the blades during flight. The location indicates a possibility that the blades were out of balance while rotating or that the crankshaft was somehow damaged in the past. No evidence of fretting was noted between the faces of the crankshaft propeller flange and the alternator pulley. The propeller assembly was attached firmly to the crankshaft.
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: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; rotorcraft: balloon
- Flight time: 7,414 hours in all; 1,800 in this make and model; 70 in the last 90 days; 15 in the last 30 days; 7,414 as pilot in command
- Last flight review: May 1, 2006
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 3,638 hours
- Last inspection: annual inspection, May 1, 2007
- Maximum gross weight: 4,100 lb
- Seats: 6
- Landing gear: retractable
- Engine: Teledyne Continental TSIO-550-C (piston); 0 hours total
The flight
- Departed from: ASE Aspen CO at 4:45 pm
- Destination: DEN Denver CO
- Flight plan: IFR
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 3 |
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.