59-26-01 HARTZELL: Applies to All HC-12X20 Propellers With Serial Numbers As Indicated Below. These Propellers May Be Installed On Such Aircraft Models As Downer (Republic) RC-3, Grumman G-44, and Navion Series.
Compliance required not later than March 1, 1960.
To preclude possible failures, remove from service Hartzell hub spiders with Serial Numbers 1 through 4303, 4307 through 4316, 4318, 4319, 4321, 4323, 4324, 4325, 4328, 4329, 4332 through 4336, 4341. After removal, these hub spiders will not be eligible for use in certificated aircraft.
Hub spiders with serial numbers other than those listed may be used as replacements.
This supersedes AD 53-06-02.