Pilot Debrief

HUEBBE Sonex HB near Plainview, IL — 2014-10-26

Final reportCEN15LA028
Sign in to save
Date
2014-10-26
Location
Plainview, IL, USA
Aircraft
HUEBBE Sonex HB
Registration
N244HB
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Cruise

Probable cause

The loss of engine power during cruise flight due to a fatigue fracture of the crankshaft, which resulted in a forced landing on unsuitable terrain.

NTSB narrative

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.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have performed engine checks before flight to ensure reliability.

NTSB coding

Evidence available

  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

Related mishaps