63-13-01 BOEING: Amdt. 579 Part 507 Federal Register June 21, 1963. Applies to All Model 75 Series Aircraft Equipped With Pratt & Whitney R-985 or Wright R-975 Series Engines and Western Propeller Repair Model W2-1 Propellers, Including Those Certificated in the Restricted Category.
Compliance required as indicated.
As a result of several propeller blade failures the following inspections are required:
Within 25 hours' time in service after the effective date of this AD, unless already accomplished within the last 225 hours' time in service, and thereafter at intervals not to exceed 250 hours' time in service from the last inspection, remove propeller blades from hub, clean surface as necessary and inspect by dye penetrant or equivalent method for evidence of cracks within the hub area and for at least 6 inches of shank portion of the blade outside of the hub. If no cracks are found blades may be returned to service. Any blades showing evidence of cracks are not eligible for repair and shall not be used again in certificated aircraft.
The repetitive inspections required on Pratt and Whitney R-985 engines in this AD are no longer necessary when the engine crankshaft flyweight and flyweight liners have been reworked or replaced at each overhaul period as detailed in AD 65-07-02.
This directive effective June 21, 1963.
Revised October 13, 1965.