AD 64-20-01

64-20-01 HARTZELL: Amdt. 803 Part 507 Federal Register August 28, 1964. Applies to Models HC-C2YK-1/7666-2 Serial Numbers AW-1 to AW-603 and HC-E2YL-2B/7663-4 Propellers Serial Numbers BG-1 to BG-777.

Compliance required as indicated.

There have been incidents of failure of the plastic pitch change blocks in Hartzell HC- E2YL-2B and HC-C2YK-1 propellers which resulted in severe roughness or vibration in flight. To correct this condition, accomplish the following:

(a) Inspect propeller blades for pitch change movement and replace plastic pitch change blocks as necessary in accordance with Hartzell Service Bulletin No. 86 revised June 17, 1964, within 10 hours' time in service after the effective date of this AD unless already accomplished within the last 10 hours' time in service, and thereafter within every 10 hours' time in service from the last inspection.

(b) When the modification specified in Hartzell Service Bulletin No. 86, revised June 17, 1964, has beenaccomplished, the repetitive inspections specified in paragraph (a) may be discontinued.

(Hartzell Service Bulletin No. 86, revised June 17, 1964, covers this same subject.)

This directive effective August 28, 1964.