Van Horn Aviation posted a new 206B3 Instructions for Continued Airworthiness VMM-206B3-301 revision that includes information for early serial number 206A/B helicopters using shorter rotor blades. Section 62.3.2 of this ICA provides the requirements for 206A/B helicopters with serial numbers 4 through 2211. Depending on the serial number, operators will use one of three procedures to modify their aircraft for the VHA tail rotor blades. Section 62.3.3. provides the mean blade angles required for helicopters of various serial numbers.