This specification covers requirements and corresponding test methods for airplane aeroelasticity. It requires that the airplane be free from flutter, control reversal, and divergence for any condition of operation within the limit V-n (velocity versus load factor) envelope and at all speeds up to the speed specified for the selected method. In addition, adequate tolerances must be established for quantities which affect flutter, including speed, damping, mass balance, and control system stiffness. The natural frequencies of main structural components must be determined by vibration tests or other approved methods.
This specification also addresses flight flutter tests to be performed to show that the airplane is free from flutter, control reversal, and divergence; dynamic evaluation for turbopropeller-powered airplanes; and modifications to the type design that could affect the flutter characteristics.
1.1 This specification covers the aeroelasticity requirements of the aeroplane. The material was developed through open consensus of international experts in general aviation. This information was created by focusing on Level 1, 2, 3, and 4 Normal Category aeroplanes. The content may be more broadly applicable; it is the responsibility of the Applicant to substantiate broader applicability as a specific means of compliance. The topics covered within this document are: 2. Referenced Documents, 3. Terminology, 4. Flutter.
1.2 An applicant intending to propose this information as Means of Compliance for a design approval must seek guidance from their respective oversight authority (for example, published guidance from applicable CAAs) concerning the acceptable use and application thereof. For information on which oversight authorities have accepted this standard (in whole or in part) as an acceptable Means of Compliance to their regulatory requirements (hereinafter “the Rules”), refer to the ASTM Committee F44 web page (www.astm.org/COMMITTEE/F44.htm). maps the Means of Compliance described in this specification to the rules of EASA CS-23, amendment 5, or later, and FAA 14 CFR Part 23, amendment 64, or later.
1.3 Units—This document may present information in either SI units, English Engineering units, or both. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.