This SAE Aerospace Recommended Practice (ARP) document provides recommended practices for the calibration and acceptance of icing wind tunnels to be used in testing of aircraft components and systems and for the development of simulated ice shapes. This document is not applicable to air-breathing propulsion test facilities configured for the purposes of engine icing tests. Use of facilities as part of an aircraft's ice protection Certification Plan should be reviewed and accepted by the applicable regulatory agency prior to testing. Following acceptance of a test plan, data generated in these facilities may be submitted to regulatory agencies for use in the certification of aircraft ice protection systems and components. Certain types of tests may be appropriate in facilities with capabilities that are not as rigorously characterized as by the practices defined herein, and the acceptability of these tests should be coordinated with the applicable regulatory agency.

Background:

The U.S. Federal Aviation Administration established an icing plan in 1997 to respond to a need for a comprehensive program to create an awareness of inflight icing issues and to establish documents to provide training and guidance for regulatory authorities, aircraft operators, research organizations, and aircraft manufacturers. The FAA published a 14-task plan, entitled the "FAA Inflight Aircraft Icing Plan," and identified groups of people within the U.S. Government and throughout the aircraft industry to address the action items contained in this plan. Task 11 of this plan called for the development of "validation criteria and data for simulation methods used to determine ice shapes on aircraft." It also indicated that this task was to include data on "wind tunnel[s], ice accretion computer codes, and icing tankers." The FAA suggested "a coordinated effort among research organizations, industry, and regulatory authorities" and individuals were asked to participate in this work. Task 11 was divided into three subtasks and the people that participated in Subtask A were tasked with addressing criteria for the use of tankers, tunnels, and codes. Three documents were developed by the members of the Task 11.A Working Group and these three documents are being published as SAE ARPs. While each document follows a format that is appropriate to the topic, the three documents provide guidance for the application of codes (ARP5903), tankers (ARP5904), and tunnels (ARP5905) to the icing certification or qualification process.

Purpose:

The purpose of this ARP is to compile in one definitive source, commonly accepted calibration and acceptance criteria and procedures for icing wind tunnels. Wind tunnels that meet these criteria will have known icing conditions simulation capability. Each manufacturer is responsible for obtaining regulatory agency approval for using a specific facility to generate certification data in their specific certification program.

The reader is directed to the following: DOT/FAA/CT-88/8-2, "Aircraft Icing Handbook," Volume 2, Chapter V, Section 4.0, Testing to Demonstrate Compliance, March 1991; "Aircraft Ice Protection," U.S. Department of Transportation, Federal Aviation Administration, Advisory Circular (AC) 20-73, April 21, 1971; "Certification of Transport Category Rotorcraft," (AC 29-2C), September 30, 1999; and the advisory circulars for icing certification of airplanes (AC 23.1419-2A and AC 25.1419-1) for the myriad of considerations that are inherent in defining and conducting test programs for the purpose of obtaining certification for flight into known icing conditions. This ARP provides recommended practices for the calibration of icing wind tunnels. It is not intended to substitute for the regulatory agency's latitude in selecting the combination of tests or inspections required to demonstrate compliance with regulations as described in the Aircraft Icing Handbook.

Facility/Site Qualification:

An icing facility that conforms to the recommended practices in this document provides an artificial icing test volume consistent with the capability provided by current wind tunnel technology. If results produced in a test facility are to be used in the certification process of aircraft components or ice protection systems, it should be substantiated that the facility calibration and supporting resources conform to this ARP. Also, a comparison between the facility icing condition envelopes that can be simulated and those defined by the regulatory authorities should be presented.