SAE ARP1401C

This SAE Aerospace Recommended Practice (ARP) covers a brief discussion of the icing problem in aircraft fuel systems and the different means that have been used to test for icing. Fuel preparation and icing test procedures for aircraft fuel systems and components are proposed herein as a recommended practice to be used for fixed wing and rotary-wing aircraft within their operational environment. This ARP mostly addresses aircraft fuel system level testing and provides a means to address the requirements of FAR 14 CFR § 23.951(c), § 25.951(c), § 27.951(c), and § 29.951(c). In the context of this ARP, the engine and the auxiliary power unit (APU) are not considered to be components of the aircraft fuel system. However, some of the methods described in this document can be applied to the engine, APU, and other aircraft (system or component level) icing tests. This revision does not completely address new developments in ice accretion and release resulting from internal flow in tubing (see 2.3.6). This will be addressed in a different document when more experimental data is available. This revision is intended to address several industry challenges pertaining to the method of conducting fuel icing tests on fuel systems and fuel components. Some of the revisions pertain to defining the target water content considering variance in fuel types and batches, introduction of the slurry injection approach to deliver the required water content, and an additional test method, “Sustained Operation,” that provides guidance to better align testing requirements with current FAA airworthiness certification standards. Additionally, methods for validation of the ice threat, clarity on test method applicability, and extensive organization to improve readability have also been included in this revision.