1.1 当一个观察者透过一个航空航天透明装置观察时，会产生相对光学畸变，特别是在厚的、角度大的多层塑料部件中。畸变发生在所有透明胶片中，但对航空航天应用尤其重要，如战斗机和商用飞机挡风玻璃、雨篷或座舱窗户。在起飞、着陆和空中加油等操作中尤其如此。能够量化采购活动中的光学失真至关重要。 1.2 本试验方法涵盖了适用于测量透明零件网格线斜率（GLS）的仪器和程序，包括小或大、薄或厚、平或曲或已安装的零件。 本试验方法不推荐用于原材料。 1.3 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3.1 例外情况- 括号中给出的值仅供参考。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 应使用本试验方法测量透明部件，如飞机挡风玻璃、雨篷、客舱窗户和遮阳板，以符合光学畸变规范。本试验方法适用于评估透明部件的光学畸变，因为它与畸变的视觉感知有关。它不适合评估失真，因为它与光通过零件时的纯角度偏差有关。任一测试方法 F801 或练习 F733 适用于后一种应用。 本试验方法不推荐用于原材料。

1.1 When an observer looks through an aerospace transparency, relative optical distortion results, specifically in thick, highly angled, multilayered plastic parts. Distortion occurs in all transparencies but is especially critical to aerospace applications such as combat and commercial aircraft windscreens, canopies, or cabin windows. This is especially true during operations such as takeoff, landing, and aerial refueling. It is critical to be able to quantify optical distortion for procurement activities. 1.2 This test method covers the apparatus and procedures that are suitable for measuring the grid line slope (GLS) of transparent parts, including those that are small or large, thin or thick, flat or curved, or already installed. This test method is not recommended for raw material. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3.1 Exception— The values given in parentheses are for information only. 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. ====== Significance And Use ====== 5.1 Transparent parts, such as aircraft windshields, canopies, cabin windows, and visors, shall be measured for compliance with optical distortion specifications using this test method. This test method is suitable for assessing optical distortion of transparent parts as it relates to the visual perception of distortion. It is not suitable for assessing distortion as it relates to pure angular deviation of light as it passes through the part. Either Test Method F801 or Practice F733 is appropriate and shall be used for this latter application. This test method is not recommended for raw material.