This document provides information, guidelines, and practices for the application, use, and administration of two-dimensional and three-dimensional droplet impingement and ice accretion computer codes. The codes provide computational simulations of inflight icing that predict droplet trajectory, water loading, and ice accretion on aircraft components. These ice accretion characteristics are used during the aircraft design and certification process.

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 11A 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 document is to provide a resource for industry and certification authorities relative to the capabilities and uses of droplet impingement and ice accretion computer codes. As with any tool, the use of droplet impingement and ice accretion codes requires some judgment on the part of the user as to whether the code is appropriate for the intended use. This document provides information, guidelines, and practices with respect to the use of these tools. These codes, when used properly, can provide the designer and airworthiness authorities with useful information about water loading and ice growth on aircraft components, and on other phenomena associated with the ice growth process.

This document describes practices used by code developers for the creation and documentation of droplet impingement and ice accretion codes and practices used by aircraft and component manufacturers when employing these codes for the design and certification or qualification of their products. Applications of these codes are described. Since other practices exist or may be developed in the future, these guidelines and practices are not considered all inclusive nor are certification authorities compelled to accept implementation of these guidelines and practices as part of an aircraft certification program.