Beechcraft King Air 360 — Service Bulletins

This service bulletin, HC-SB-61-305, issued by Hartzell Propeller Inc. on June 26, 2008, addresses critical safety concerns regarding the propeller mounting bolts on specific Beechcraft King Air models. It applies to the King Air C90GT, B200GT, B300, and B300C aircraft equipped with Hartzell propellers installed in 2007 or 2008. The bulletin outlines the necessary inspections and replacement procedures for propeller mounting bolts to prevent potential propeller separation, which could lead to severe accidents. The document emphasizes the importance of torque specifications and provides compliance timelines for inspections and replacements based on the total time since new (TSN) of the propellers. Pilots and maintenance personnel are advised to follow the instructions closely to ensure safety and compliance with FAA regulations.

• Affected aircraft models include Beechcraft King Air C90GT, B200GT, B300, and B300C.
• Propeller mounting bolts must be inspected and potentially replaced to prevent propeller separation.
• Normal installation torque for mounting bolts is 100 to 105 ft-lbs (136 to 142 N•m).
• A breakaway torque check should be performed at 90 ft-lbs (122 N•m) to ensure bolts are not over-torqued.
• Immediate action is required for propellers with over 600 hours TSN to replace mounting bolts.