Piper PA-31-350 accident near Sweeny, Texas, September 14, 2004
On September 14, 2004 at about 11:15 pm local time, a Piper PA-31-350, registered N555MC, was substantially damaged in an accident near Sweeny, Texas. 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
The fracture failure of the left engine crankshaft for undetermined reasons.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 14, 2004 · about 11:15 pm local time
- Place
- Sweeny, Texas · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-31-350 · all PA-31-350s on the register
- Registration
- N555MC · no longer on the register · serial 31-7752154
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The 1,800-hour commercial pilot reported that while in cruise flight, the left engine stopped producing power and the left propeller fell forward approximately six inches. The pilot secured the engine and made a precautionary landing. The airplane sustained substantial damage during the forced landing to a field. A review of aircraft maintenance records revealed that the airplane experienced a gear-up landing in January 2002, which resulted in a propeller strike. The left engine was removed and inspected per the manufacturer's overhaul manual and returned to service. The engine had accrued approximately 440 hours since it was overhauled. Examination of the engine revealed that the entire three-bladed propeller assembly and the #1 cylinder had separated from the engine. The engine was disassembled and the crankshaft, along with an intact #3 connecting rod assembly and the fractured #2 connecting rod assembly were examined by a Safety Board Materials Engineer. The crankshaft was fractured in two places; one fracture was just forward of the #3 rod journal in the crank cheek, and the other fracture was in the aft crank cheek adjacent to the #2 main journal. The interior surface of the #1 and #2 main bearing halves exhibited significant rubbing and a portion of the bearing liner material was delaminated and was missing from the forward end of the bearing. On the oil slinger face, just forward of the #1 main journal, 360 degree rubbing damage was noted just outboard of the radius. In the rub region, metallic transfer was present with a color consistent with aluminum material. No evidence of radial cracks was observed in this area. An exact determination for the crankshaft failure could not be determined; however, evidence supported two possibilities that could have attributed to its demise. One possibility was that the crankshaft fracture initiated from rubbing damage between the crank cheek aft of the #2 main journal (thrust face) and the crankcase, with the other fatigue region being secondary. The exact cause for the rubbing was not clear, but one possibility was that the bearing liner delaminated and liberated a section causing a reduction in the clearance between the crankshaft and the crankcase as it was rubbing/exiting through the oil slinger. The other possibility was that the propeller strike caused the rubbing/cracking to occur, which was not detected during the subsequent overhaul/inspection.
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: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 1,800 hours in all; 20 in this make and model; 210 in the last 90 days; 130 in the last 30 days; 1,700 as pilot in command; 1,450 on instruments
- Last flight review: February 1, 2004
- Medical certificate: Class 1
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 6,542.1 hours
- Last inspection: annual inspection, August 1, 2004
- Maximum gross weight: 6,500 lb
- Seats: 6
- Landing gear: retractable
- Engine: Lycoming TIO-540-J2BD (piston); 0 hours total
The flight
- Departed from: T97 Port Lavaca TX at 10:45 pm
- Destination: HOU Houston TX
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 180° at 5 knots
- Visibility: 10 statute miles
- Sky: scat at 8,000 ft
- Temperature: 90°F (32°C), dew point 79°F (26°C)
- Altimeter: 29.82 inHg
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.