58-22-01 HAMILTON STANDARD: Applies to All 6800, 6900, and 7000 Series Externally Surface-Treated Aluminum Alloy Blades (Airfoil Shotpeened and/or Shank Rolled, Including Nickel-Plated Blades).
Compliance required at first blade overhaul after January 1, 1959, and at every overhaul thereafter.
Two surface-treated aluminum alloy blades have fractured during operation. Blade bending may have, depending on the circumstances surrounding the incident, a serious detrimental effect on the fatigue strength of a blade. Therefore, it is considered necessary to establish a means to detect and evaluate instances of unrecognized blade bending by systematically comparing at overhaul measured face alinement values with previously established values. To establish such a means, follow the detailed instructions contained in Hamilton Standard Service Bulletin No. 546. This procedure requires that face alinement measurements be made prior to any overhaul, and then again following all operationsthat would affect face alinement.
(Hamilton Standard Service Bulletins Nos. 546 and 546A cover this same subject.)