91-82 - Fatigue Management Programs for Airplanes with Demonstrated Risk of Catastrophic Failure Due to Fatigue

Date Issued
April 29, 2008
Responsible Office
ACE-100,  Small Airplane Directorate

a. This advisory circular (AC) provides guidance on developing and implementing a Fatigue Management Program (FMP). An applicant may develop an FMP as one method to address the unsafe condition that arises when the Federal Aviation Administration (FAA) has determined an airplane type design has an unsafe condition associated with a demonstrated risk of catastrophic failure due to fatigue (hereinafter referred to as demonstrated risk). An FMP incorporates damage-tolerance based inspections or a part replacement/modification program to mitigate the demonstrated risk. An FMP also incorporates inspections based on service history and engineering judgment to address the broader risk posed by potential cracking of other fatigue critical structure in the airplane. The FAA may mandate an FMP by Airworthiness Directive (AD) only in cases in which the FAA has determined that airworthiness action is necessary to address an unsafe condition. The FAA may also approve an FMP as an alternative method of compliance (AMOC) to an AD. b. This AC provides guidance for actions once the FAA determines that an AD is necessary to address the unsafe condition associated with a demonstrated risk. Existing FAA guidance supports development of damage-tolerance based inspection programs for transport category airplanes to look proactively for potential cracks. Such guidance includes AC 91-56B, Continuing Structural Integrity Program for Airplanes, and AC 25.571-1C, Damage Tolerance and Fatigue Evaluation of Structure. These existing ACs do not describe all the actions that should be used to address a demonstrated risk. c. This AC is not mandatory and does not constitute a regulation. It describes an acceptable means, but not the only means, for maintaining the continued operational safety for airplane type designs that have a demonstrated risk. However, if you use the means described in this AC, you must follow it in all important aspects. In this AC, we use terms such as “must” or “require” only in the sense of ensuring applicability of a particular method of compliance when you use a specific acceptable method of compliance described herein.


Number Title Date
91-60 The Continued Airworthiness of Older Airplanes 06/13/1983