Mechanical & Engine Failure · NTSB CEN15LA028
HUEBBE Sonex HB — Plainview, IL
| Date | October 26, 2014 |
| Location | Plainview, IL |
| Aircraft | HUEBBE Sonex HB (amateur-built) |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Enroute-cruise Loss of engine power (total) |
| Pilot age | 66 |
| Pilot total time | 2,500 hrs · Experienced |
| Time in type | Unknown |
| Fatalities | 1 |
Probable cause
NTSB findings
- Aircraft-Aircraft power plant-Power plant-(general)-Fatigue/wear/corrosion - C
- Environmental issues-Physical environment-Terrain-Wet/muddy terrain-Effect on equipment - C
- Aircraft-Aircraft power plant-Power plant-(general)-Failure - C
What happened
The private pilot and a sport pilot-rated passenger were conducting a personal cross-country flight in the experimental amateur-built airplane, which was powered by an uncertified automotive engine. The airplane was in cruise flight when it experienced a total loss of engine power. The pilot(s) attempted a forced landing on a field, during which the airplane nosed over. The wreckage path through the field was about 200 ft long, which was consistent with excessive energy/speed upon touchdown.
A review of maintenance logbook entries revealed that the engine had been assembled by the owner and that the camshaft and crankshaft had been removed when work was performed on the engine about 3 years before the accident. Postaccident examination of the engine indicated that the crankshaft had fractured due to a fatigue crack that had initiated at a fillet radius at the forward end of the No. 2 main bearing journal where the journal transitioned to the forward cheek. The cause of the fatigue crack could not be determined.