EASA SIB 2008-36
FAA SAIB NE-08-18 - Potential for propeller failure due to high vibratory stress induced by worn or improper engine crankshaft dampers
Summary
FAA Special Airworthiness Information Bulletin (SAIB) NE-08-18 and EASA Safety Information Bulletin (SIB) No. 2008-36 address the potential for propeller failure caused by high vibratory stress due to worn or improperly installed engine crankshaft dampers. This issue affects propellers installed on general aviation aircraft certified under Parts 22 and 23, as well as transport category aircraft under Part 25. The bulletins highlight risks associated with various propeller manufacturers including Hamilton Sundstrand, Hartzell, McCauley, and others.
What Changed
This bulletin introduces awareness and recommendations regarding the impact of worn or improper crankshaft dampers on propeller vibratory stress and potential failure. It emphasizes that propeller approvals are based on specific engine and damper configurations, and deviations can increase vibratory stress. The document does not mandate actions but provides guidance to mitigate risks associated with damper wear, damage, or improper installation.
Why It Matters
Understanding the effect of crankshaft dampers on propeller life is critical for aviation professionals to prevent unexpected propeller failures. Operators and maintenance personnel must recognize that improper maintenance or installation of dampers can lead to increased vibratory stress, which is often undetectable by pilots but can cause catastrophic propeller damage. This information supports safer operation and maintenance practices, reducing the risk of in-flight failures and costly repairs.
What To Do
Operators and maintenance organizations should perform timely and proper maintenance of engines, propellers, and crankshaft dampers, following manufacturer recommendations for inspection and replacement of damper pins and bushings during overhauls. They should monitor for changes in vibration patterns and avoid unapproved engine/propeller combinations. No mandatory compliance deadline is specified, but adherence to recommended practices is strongly advised to ensure safety.
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