CESSNA 310F — Weight & Balance

This Service Letter No. 076 addresses the inspection and maintenance of South Wind combustion heaters installed in various aircraft models, including the Cessna 421C. It outlines the affected heater models, the potential risks associated with heater deterioration, and the necessary actions to ensure compliance with Airworthiness Directive (AD) 2017-06-03. The document provides options for replacing or overhauling affected heaters and emphasizes the importance of using the most current information for safety. It serves as a critical reference for aircraft owners and maintenance personnel to maintain airworthiness and safety standards.

• Affected heater models include South Wind combustion heaters 921, 930, 937, 940, 944, 945, 977, 978, 979, 8240, 8253, 8259, and 8472.
• Airworthiness Directive (AD) 2017-06-03 mandates inspection and repair of affected heaters.
• Heater replacement options include overhauled exchange units and new exchange units, as detailed in Table 1.
• It is crucial to verify the installation of affected heaters to maintain safety and compliance.
• Contact Hartzell Engine Technologies for technical support regarding this service letter.