Robinson R44 Cadet — Service Bulletins

This Airworthiness Bulletin (AWB 85-024 Issue 3) addresses the issue of premature exhaust valve and valve guide wear in Robinson R22 and R44 helicopters, specifically those fitted with Lycoming O-360 and O-540 series engines. It is intended for owners, operators, pilots, maintenance organizations, and licensed aircraft maintenance engineers. The bulletin highlights the increasing incidence of this wear, particularly in high ambient temperature regions, and provides recommendations for monitoring and maintenance to mitigate the risk of engine performance degradation. While the recommendations are not mandatory, they are crucial for maintaining airworthiness and operational safety.

• Applicable to Robinson R22 Beta II, R22 Mariner II, R44 Raven I, and R44 Cadet helicopters.
• Premature exhaust valve and valve guide wear can lead to significant engine performance issues.
• Strict adherence to operational limitations is crucial, especially in high ambient temperatures.
• Regular maintenance and inspections are essential to monitor valve and guide condition.
• Fuel quality and handling are critical to maintaining engine integrity.