Pilot Debrief

Lacour Long-EZE SR7-1 near Falfurrias, TX — 2010-03-01

Final reportCEN10LA131
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Date
2010-03-01
Location
Falfurrias, TX, USA
Airport
BKS
Aircraft
Lacour Long-EZE SR7-1
Registration
N97EZ
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

A total loss of engine power due to a failure of the crankshaft behind the No. 3 connecting rod journal for undetermined reasons.

NTSB narrative

The pilot reported that he was in level cruise flight at 3,500 feet mean sea level when the engine suddenly vibrated then seized. The pilot made a "firm" forced landing on rolling brush and rock-strewn terrain. During the landing roll, the landing gear was sheared off and the canard wing was crushed. Engine disassembly revealed case fretting and main bearing movement. A representative of the engine manufacturer indicated that the failure mode was extremely rare, if not unique. The pilot had installed a Hertzler “Silver Bullet” composite propeller to the extended hub. According to the representative, it was possible that a harmonic vibration could have emanated from the propeller through the extended hub to the crankshaft. However, this propeller had not been tested to determine if there were amplified propeller harmonics to the crankshaft and the investigation was unable to determine that such vibration led to the engine failure.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have conducted a pre-flight engine inspection to identify potential issues.

NTSB coding

Evidence available

  • Photos
  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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