On July 21, 1996, a Cessna 172XP (registration N736LB) was involved in an aviation accident near Kenai, AK. Investigators recorded the probable cause as: The loss of engine power due to seized piston connecting rod bearings, and subsequent failure of the piston connecting rod cap and fracture of the piston connecting rod. A factor associated with the accident was the rough and uneven emergency landing site. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
While exiting a mountain pass, the airplane's engine lost all power. The pilot attempted restart but failed, then performed an emergency landing on a rough gravel bar. Examination revealed a fractured #2 cylinder connecting rod.
Incident Details
While exiting a mountain pass, the airplane's engine suddenly lost all power. The pilot attempted to restart the engine but was unsuccessful. He then performed an emergency landing on a rough gravel bar.
Engine Examination
During the engine examination, the #2 cylinder piston connecting rod was found fractured and separated from the crankshaft. The #2 piston connecting rod cap and cap bolts were also fractured and separated from the crankshaft. The #2 piston connecting rod journal was rough and abraded. The piston connecting rod cap bolts had fractured about mid span, and the fracture ends were stretched and necked down. The castellated nuts used to secure the rod cap were found still attached to their respective rod cap bolts. No other mechanical anomalies were discovered during the engine examination.
Recovery and Oil Drainage
The mechanic who recovered the airplane from the accident site indicated that he drained at least 6 quarts of oil from the engine prior to the recovery.
Frequently asked questions
What happened in the 21 Jul 1996 Cessna 172XP accident near Kenai, AK?
While exiting a mountain pass, the airplane's engine lost all power. The pilot attempted restart but failed, then performed an emergency landing on a rough gravel bar. Examination revealed a fractured #2 cylinder connecting rod.
What aircraft was involved and where did it happen?
The accident on 21 Jul 1996 involved a Cessna 172XP, registration N736LB, at Kenai, AK.
What was the probable cause of the accident?
The loss of engine power due to seized piston connecting rod bearings, and subsequent failure of the piston connecting rod cap and fracture of the piston connecting rod. A factor associated with the accident was the rough and uneven emergency landing site.
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