Lycoming Engines — Possible Failure of thru-Studs and/or Cylinder Mount Studs
- Published
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Inspect cylinder studs and thru-studs for corrosion pits and missing cadmium plating regularly. Follow Lycoming's overhaul manual and Service Instruction No. 1029D for proper cylinder installation and use the recommended special tools to achieve correct torque. Additionally, inspect crankcase main bearing mating surfaces for fretting where accessible, as no fretting is allowed.
Summary
The FAA Special Airworthiness Information Bulletin SAIB: NE-14-13 addresses the possible failure of thru-studs and cylinder mounting studs on Lycoming Engines. It highlights incidents of cylinder mounting stud failures due to corrosion and fatigue, particularly involving the absence or degradation of protective cadmium plating. The bulletin is informational and does not mandate regulatory action but provides guidance for operators and maintenance personnel of Lycoming engines.
What changed
This bulletin introduces awareness of potential stud failures linked to corrosion pits and improper installation practices on Lycoming engine cylinder studs. It recommends enhanced inspection and maintenance practices to prevent stud failures but does not impose new mandatory requirements or airworthiness directives.
Why it matters
Understanding the risk of cylinder mounting stud failure is critical for aviation professionals to maintain engine integrity and safety. Operators and maintenance organizations must be vigilant in inspecting studs for corrosion and ensuring proper installation torque to avoid fatigue failures that could lead to engine damage or operational hazards. This information supports proactive maintenance and risk mitigation for Lycoming-powered aircraft.
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