Subject: VIBRATION AND FATIGUE
EVALUATION OF AIRPLANE PROPELLERS
Date: 9/17/01
Initiated By: ANE-110
AC No: 20-66A
Change:
1. PURPOSE. This advisory circular (AC) provides guidance and describes one method, but
not the only method, for demonstrating compliance with §§23.907 and 25.907 of Title 14 of the
Code of Federal Regulations, for the evaluation of vibration stresses on propellers installed on
airplanes. Like all AC material, this AC is not, in itself, mandatory and does not constitute a
regulation. While these guidelines are not mandatory, they are derived from extensive Federal
Aviation Administration (FAA) and industry experience in determining compliance with the
pertinent regulations.
2. CANCELLATION. AC 20-66, Vibration Evaluation of Airplane Propellers, dated 1/29/70,
is canceled.
3. RELATED DOCUMENTS.
a. Regulations. Sections 35.4, 35.37, 23.907, and 25.907.
b. Advisory Circulars.
(1) AC 35.37-1A, Guidance Material for Fatigue Limit Tests and Composite Blade
Fatigue Substantiation, dated 9/17/01.
(2) AC 20-107A, Composite Aircraft Structure, dated 4/25/84.
(3) AC 21-26, Quality Control for the Manufacture of Composite Structures, dated
6/26/89.
(4) AC 25.571-1C, Damage Tolerance and Fatigue Evaluation of Structure, dated 4/29/98.
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