Plainview, IL, USA
N244HB
HUEBBE Sonex HB
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.
**This report was modified on August 2, 2016. Please see the docket for this accident to view the original report.* On November 26, 2014, at 1550 central daylight time, an experimental amateur-built Huebbe Sonex HB, N244HB, nosed-over during a forced on a field during near Plainview, Illinois. The airplane experienced a total loss of engine power during cruise flight. The pilot sustained fatal injuries and a sport pilot rated passenger sustained minor injuries. The airplane was registered to and operated by the pilot under Title 14 Code of Federal Regulations Part 91 as a personal flight that was not operating on a flight plan. Visual meteorological conditions prevailed for the flight that departed from Taylorville, Illinois, and was destined to St. Charles, Missouri. According to the Federal Aviation Administration inspector that performed an on-scene examination of the airplane, the wreckage path of the airplane extended about 45-75 feet through a cut agricultural field and then about 160 feet through a corn plants/field. The airplane was resting inverted. The airplane flaps were extended. The inspector stated that there was useable fuel aboard the airplane, and he confirmed flight control continuity. The pilot, age 66, held a private pilot certificate with a single-engine land rating and a repairman experimental aircraft builder certificate. He reported on his last airman medical application dated May 24, 2004, a total flight time of 2,500 hours, of which 40 hours in last six months as of exam dated 05/24/2004. The pilot's last airman medical certificate was a Third Class Medical Certificate with the following limitation(s): None. An autopsy of the pilot was conducted by the Macoupin County Coroner's Office, which reported the cause of death as "blunt force injuries to head and neck" and the manner of death as "airplane crash". The Federal Aviation Administration Final Forensic Toxicology Fatal Accident Report of the pilot stated VOLATILES: No Ethanol detected in Vitreous; CYANIDE: Not Performed; CARBON MONOXIDE: No Carbon Monoxide detected in Blood (Heart); Diclofenac detected in Urine; Dihydrocodeine detected in Urine; Dihydrocodeine detected in Liver; Dihydrocodeine detected in Blood (Femoral); 0.693 (ug/ml, ug/g) Hydrocodone detected in Urine; 0.067 (ug/ml, ug/g) Hydrocodone detected in Liver; 0.024 (ug/ml, ug/g) Hydrocodone detected in Blood (Femoral); Hydromorphone detected in Urine; Hydromorphone NOT detected in Blood (Femoral); Trazodone detected in Urine; 0.058 (ug/mL, ug/g) Trazodone detected in Blood (Heart). N244HB was a 2010 Sonex HB, serial number 24, was built by the pilot, passenger, and the passenger's brother. The airplane logbook contained the following entries: Date Total Time, hrs Event March 20, 2010 0 Engine installed on airplane. November 20, 2011 222.08 Remove engine, replace lifters and cam, lap valves. July1, 2012 222.08 Break in cam and lifters. August 10, 2014 300.4 Last inspection prior to accident. Post-accident disassembly examination of the engine from a Great Plains Aircraft Supply kit engine revealed that the crankshaft was fractured. The engine crank case halves had the following inscription with Volkswagen/Audi symbols: "AS-41," and "043.101.101.A". The crankshaft was sent to the National Transportation Safety Board (NTSB) Materials Laboratory for examination. The Materials Laboratory examination of the crankshaft revealed that it was fractured through the forward cheek of the number two main bearing (with numbering starting from the aft end of the engine). The camshaft was fractured between the number one and number two lobes (with numbering starting from the aft end of the engine). The crankshaft fracture surface was comparatively flat and exhibited a series of curved crack arrest marks. The features were consistent with a fatigue crack initiating at the intersection of the number two main bearing journal with the forward cheek. Visual examination revealed that the transition from the journal to the cheek consisted of a small radius fillet that blended into a large radius fillet. The journal was sectioned through the transition with an abrasive cutting saw and photographed. The radius of each fillet was measured on the calibrated digital image. The fillet radii were approximately 0.090 inch and 0.014 inch for the large and small radius fillets, respectively. The transition from the number two journal to its aft cheek and the number one journal to its forward cheek similarly exhibited small diameter and large diameter fillet radii. The registered owner who was also the passenger's brother stated that the engine for N244HB was purchased as a kit from Great Plains Aircraft Supply Company. The kit consisted of engine parts that he assembled from supplied instructions/plans. He said there was no engine serial number. He said that the maintenance work to the lifters cited in the aircraft logbook was due to a notification from Great Plains Aircraft Supply Company for pitting of the engine lifters. The camshaft as well as the crankshaft had to be removed when work to the lifters was performed. The crankshaft bearings and the crankshaft were never changed since the engine was first assembled.
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.
Source: NTSB Aviation Accident Database
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