F07.08 - Transparent Enclosures and Materials

SIGNIFICANCE AND USE
4.1 This practice is useful as a screening basis for acceptance or rejection of transparencies during manufacturing so that units with identifiable flaws will not be carried to final inspection for rejection at that time.  
4.2 This practice may also be employed as a go-no go technique for acceptance or rejection of the finished product.  
4.3 This practice is simple, inexpensive, and effective. Flaws identified by this practice, as with other optical methods, are limited to those that produce temperature gradients when electrically powered. Any other type of flaw, such as minor scratches parallel to the direction of electrical flow, are not detectable.
SCOPE
1.1 This practice covers a standard procedure for detecting flaws in the conductive coating (heater element) by the observation of polarized light patterns.  
1.2 This practice applies to coatings on surfaces of monolithic transparencies as well as to coatings imbedded in laminated structures.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 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. For specific precautionary statements, see Section 6.  
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 The basic material properties obtained from this test method can be used in the control of the quality of interlayers, in the theoretical equations for designing laminated transparencies, and in the evaluation of new interlayers.
SCOPE
1.1 This test method covers the determination of the shear strength and shear modulus of interlayer materials that are restrained by relatively high modulus plies in laminated transparencies. This test method can be used with single or multiple plies of the same interlayer materials.  
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.  
1.3 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.  
1.4 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 Significance—This test method provides a means to measure the transmissivity of parts in the field (already installed on aircraft) and of large, thick or curved parts physically difficult to measure using Test Method D1003.  
5.2 Use—This test method is acceptable for use on any transparent part. It is primarily intended for use on large, curved, or thick parts either pre- or post-installation (for example, windscreens on aircraft).
SCOPE
1.1 This test method describes an apparatus and procedure that is suitable for measuring the transmissivity of large, thick, or curved transparent parts including parts already installed. This test method is limited to transparencies that are relatively neutral with respect to wavelength (not highly colored).  
1.2 Since the transmissivity (transmission coefficient) is a ratio of two luminance values, it has no units. The units of luminance recorded in the intermediate steps of this test method are not critical; any recognized units of luminance (for example, foot-lamberts or candelas per square metre) are acceptable for use, as long as use is consistent.  
1.3 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.  
1.4 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
3.1 This guide is intended for use by material suppliers, aircraft transparent enclosure fabricators, airframe manufacturers, government agencies, and others that may become involved in the testing of transparent interlayer materials. These test methods provide data on both individual interlayer materials and material combinations commonly used in the fabrication of aerospace transparent enclosures and provide a means of evaluating the performance of one interlayer material against another.  
3.2 Primary characteristics and their long-term stability are critical to the performance of an interlayer material. Basic tests define the as-manufactured material characteristics of the interlayer material. Aging procedures provide for representative exposure to environments that induce changes in material characteristics. Tests performed before and after ageing exposure provide a means of estimating the potential useable life-span of an interlayer material or to compare the durability of one interlayer material with another.  
3.3 When employing these test methods for the comparison of interlayer materials after exposure to selected environmental conditions, the user shall be aware that many factors influencing degradation due to weathering vary from one location and exposure period to another location and exposure period. For direct weathering comparisons, the interlayer materials to be compared shall be subjected to the exposure and have the tests performed at the same time. It is emphasized that the test values obtained under these simultaneously applied conditions are for comparative use and their use as design characteristics shall be made with caution.  
3.4 The test methods listed include those considered critical to the performance of aircraft transparent enclosures. The user is advised to use the latest revision of any test method.
SCOPE
1.1 This guide summarizes the standard test methods available for determining physical and mechanical characteristics of interlayer materials used in multi-ply aerospace transparent enclosures.  
1.2 Interlayer materials are used to laminate glass-to-glass, glass-to-plastic, and plastic-to-plastic. Interlayer materials are basically transparent adhesives with high-quality optical properties. They can also serve as an energy absorbing medium, a fail-safe membrane to contain cockpit pressure and to prevent entry of impact debris; a strain insulator to accommodate different thermal expansion rates of members being laminated and as an adherent to prevent spalling of inner surface ply material fragments. The relative importance of an interlayer characteristic will be a function of the prime use it serves in its particular application.  
1.3 This guide, as a summary of various methods in Section 2, is intended to facilitate the selection of tests that can be applied to interlayer materials.  
1.4 The test methods listed are for use in determining basic design characteristics and in assuring lot-to-lot uniformity of the materials being tested except as noted in 3.3.  
1.5 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.  
1.6 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 This test method is applicable for qualitatively evaluating coated and uncoated monolithic polycarbonate sheet material, for monitoring process control, for screening studies, and as an aid in the prediction of hardware performance when exposed to impact service conditions.  
5.2 A limitation of Type A specimen testing is that a thick sheet may not fail since the available impact energy is limited by the maximum drop height and falling weight capacity of the test apparatus. Use Specimen Type A for material less than 12.7 mm (0.50 in.) thick.  
5.3 Within the range of drop heights of this system, tests employing different velocities are not expected to produce different results. However, for a given series of tests, the drop height should be held constant so that velocity of impact (strain rate) will not be a variable.  
5.4 As the polycarbonate specimen undergoes large plastic deformation under impact, the down (opposite impact) side is under tensile loading and most influential in initiating failure. For that reason, polycarbonate sheet coated on one side should be tested with the coated side down.  
5.5 Direct comparison of specimen Type A and specimen Type B test results should not be attempted. For test programs that will require the comparison of interlaboratory test results the specimen type and the approximate drop height must be specified.  
5.6 Monolithic polycarbonate sheet is notch sensitive. Data obtained from other test methods, particularly notched Izod/Charpy test results, and extremely high- or low-strain rate test results, should not be compared directly to data obtained from this method. It is noted that Type A specimens, free of flaws, have not experienced the characteristic ductile-to-brittle transition between thin, less than 3.18 mm (1/8 in.), and thick, greater than 7.94 mm (5/16 in.), sheet as reflected by other test methods.
SCOPE
1.1 This test method covers the determination of the energy required to initiate failure in monolithic polycarbonate sheet material under specified conditions of impact using a free falling weight.  
1.2 Two specimen types are defined as follows:  
1.2.1 Type A consists of a flat plate test specimen and employs a clamped ring support.  
1.2.2 Type B consists of a simply supported three-point loaded beam specimen (Fig. 1) for use with material which can not be failed using the Type A specimen. For a maximum drop height of 6.096 m (20 ft) and a maximum drop weight of 22.68 kg (50 lb), virgin polycarbonate greater than 12.70 mm (1/2 in.) thick will require use of the Type B specimen.  
Note 1: See also ASTM Methods: D1709, D2444 and D3029.
FIG. 1 Type B Specimen Geometry and Loading  
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 inch-pound units in parentheses are provided 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. For specific hazard statement, See Section 7.  
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
4.1 This test method provides a guide for evaluating whether a specific solvent, chemical, or compound is detrimental to a transparent plastic as a result of a manufacturing process, a fabrication operation, or the operational environment. All transparent plastics are susceptible to crazing, though in widely varying degree and from a variety of causes. This test method is intended to allow establishment of the crazing stress when the simultaneous action of both load and a material that will cause crazing is applied, producing non-reversible damage that limits the usage of that transparent plastic in a specific application.
SCOPE
1.1 This test method covers the determination of the critical crazing stress for a transparent plastic material when exposed to a specific solvent, chemical, or compound at a specific temperature.  
1.2 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.  
1.3 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
3.1 This guide is intended for use by material suppliers, aircraft transparent enclosure fabricators, air-frame manufacturers, government agencies, and others that may become involved in the testing of transparency components. These test methods provide data on both individual materials and material combinations commonly utilized in the fabrications of aerospace transparent enclosures comprised of monolithic plastic, coated monolithic plastic or laminated constructions containing plastics.  
3.2 Primary properties and their long term stability are critical to the performance of aerospace transparent enclosures. Property measurement tests define as-manufactured material properties of these materials. Aging procedures provide for exposure of parts or representative sections to environments that induce changes in material properties as determined in property measurement tests. Property measurement tests performed before and after aging exposure provide a means of estimating the potential usable life span of a transparency or to compare the durability of one material with another.  
3.3 When employing these test methods for comparison of materials for weathering effects the user should be aware that the many factors influencing degradation due to weathering vary from one location to another. For direct weathering comparisons, all material(s) shall undergo exposure conditions and property measurements testing at the same time.  
3.4 The test methods listed include those considered critical to the performance of aircraft transparent enclosures. Other test methods to evaluate materials shall also be performed where necessary. Additional test methods are in preparation and will be incorporated. The user is advised to employ the latest revision of any test method.  
3.5 The dominant component of all transparent enclosures is one, or more, rigid transparent sheet(s). The sheet(s) must permit the necessary visibility while providing structural integrity and protecting the ...
SCOPE
1.1 This guide is intended to summarize the standard test methods available on individual and composite materials utilized in fabrication of aerospace plastic transparent enclosures. As such, it is intended to specifically include transparent thermoplastics, transparent elastomers, and reinforced plastics, whether thermoplastic or thermosetting.  
1.2 This guide is intended as an aid in the search for test methods pertinent to Aerospace Plastic Transparent Enclosures. It should be understood that all methods listed may not apply to all enclosures.  
1.3 The standards included refer to the properties or aspects listed in Table 1. The properties or aspects are listed in alphabetical order and the descriptions used are intended to facilitate the search.  
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
4.1 Plastic materials, when used as transparencies, covers, or enclosures, are subject to wiping, cleaning, or other types of rubbing actions that cause abrasion. It is the intent of this test method to provide a means of estimating the resistance of such materials to this type and degree of abrasion.
SCOPE
1.1 This test method determines the resistance of transparent plastics and transparent coatings utilized in windows or viewing ports to surface abrasion using oscillating sand.  
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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.  
1.4 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 At this writing, aerospace quality extruded transparent polycarbonate material is not available in thicknesses greater than 0.5 in. (12.7 mm). When a requirement exists for sheets thicker than 0.5 in. (12.7 mm), two or more sheets are fusion bonded together to form a single sheet of the desired thickness.  
5.2 The structural integrity of the completed transparency depends on the integrity of the fusion bond. This test applies torsional shear loads to measure the structural integrity of the fusion bond. This test method is considered more reliable and more reproducible than shear tests in tension or compression.
SCOPE
1.1 This test method determines the shear yield strength Fsy   and shear ultimate strength Fsu   of fusion bonds in polycarbonate by applying torsional shear loads to the fusion-bond line.  
1.2 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.  
1.3 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
4.1 Prisms are useful tools for viewing areas otherwise obstructed or hidden from normal viewing. For example, transparency bolt holes, voids, and delaminations that are covered by edge strips or frames can be seen through a prism. The prism, once put against the transparency, with a coupling agent to wet the surfaces, allows viewing of the area below where the prism is placed.
SCOPE
1.1 Aerospace transparencies undergo high stresses induced by flight, environmental, or other factors. The transparency attachment points are especially subject to fatigue. These areas of fatigue are often obstructed or hidden from normal inspection. An inspector, following the techniques described in this practice, shall use a prism to view damage located near transparency bolt holes, voids, and delamination that are hidden by edge strips or frames.  
1.2 The purpose of this practice is to provide acceptable methods for performing prism inspections of transparent materials with specific emphasis on aircraft windscreens and canopies. Caveats and lessons learned from experience are included to assist authors in writing tailored inspection instructions for specific applications.  
1.3 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.  
1.4 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.
SCOPE
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
4.1 These test methods provide a means to measure quantitatively the bond integrity between the outer layers of the transparency and the interlayer, or to measure the cohesive properties of the interlayer, under various loading conditions.  
4.2 These test methods provide empirical results useful for control purposes, correlation with service results, and as quality control tests for acceptance of production parts.  
4.3 Test results obtained on small, laboratory-size samples shown herein are indicative of full-size part capability, but not necessarily usable for design purposes.
SCOPE
1.1 These test methods cover determination of the bond integrity of transparent laminates. The laminates are usually made of two or more glass or hard plastic sheets held together by an elastomeric material. These test methods are intended to provide a means of determining the strength of the bond between the glass or plastic and the elastomeric interlayer under various mechanical or thermal loading conditions.  
1.2 The test methods appear as follows:    
Test Methods  
Sections  
Test Method A—Flatwise Bond Tensile Strength  
5 – 11  
Test Method B—Interlaminar Shear Strength  
12 – 17  
Test Method C—Creep Rupture  
18 – 25  
Test Method D—Thermal Exposure  
26 – 30  
1.3 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.  
1.4 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 All materials on exterior aircraft surfaces are subject to abrasion from airborne particles of various sizes and shapes. Transparent materials are particularly vulnerable to abrasion, since their performance is based on their ability to transmit light with a minimal amount of scatter. Scratches, pitting, and coating removal and delamination as a result of abrasion may increase scatter, reduce transmission, and degrade the performance of transparent materials. Visually transparent materials are required for pilot and air crew enclosures, such as canopies, windshields, and viewpoints. Materials transparent in the IR region (8 to 12 μm) are required for tracking, targeting, and navigational instrumentation.  
5.2 This test method is intended to provide a calibrated and repeatable means of determining the relative abrasion resistance of materials and coatings for optical and IR transparent materials and coatings. The test parameters for this test method can be directly related to dust cloud densities and velocities to which transparent materials are exposed in the field.
SCOPE
1.1 This test method covers the resistance of transparent plastics and coatings used in aerospace windscreens, canopies, and viewports to surface erosion as a result of dust impingement. This test method simulates flight through a defined particle cloud environment by means of independent control of particle size, velocity, impact angle, mass loading, and test duration.  
1.2 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.  
1.3 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
4.1 This test method shall be used for: bird impact testing of aircraft crew compartment transparencies and supporting structure to verify the design; compilation of test data for use in verification of future transparency and supporting structure design and analytical methods; and comparative evaluation of materials.
SCOPE
1.1 This test method covers conducting bird impact tests under a standard set of conditions by firing a packaged bird at a stationary aerospace transparency (windshield, canopy, or window) mounted in a support structure.  
1.2 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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. For specific hazard statements, see Section 8.  
1.4 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.

SCOPE
1.1 These definitions cover generic optical terms which appear in one of more standards relating to aerospace transparent materials and enclosures.  
1.2 The definitions cover, in most cases, special meanings used in the transparency industry. No attempt has been made to include common meanings of the same terms as used outside of the transparency industry.  
1.3 Definitions included have, in general, been approved as standard.  
1.4 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
4.1 Reflections from aircraft transparencies of instrument lights and other cockpit objects have been a concern to many pilots. Attempts to reduce these reflections have been hampered by the lack of a repeatable measurement method and variances in reflection measuring instrumentation.  
4.2 This test method reduces the instrument variations by standardizing the light source, calculation method, and area of specimen surface being measured; a brand of instrumentation is not specified. Since the reflectivity is defined as the ratio of two luminance measurements and does not depend on an absolute measurement, dependence upon the accuracy of the calibration of the measuring instrument is reduced.  
4.3 The test method may be used to objectively compare the reflection characteristics of various transparent materials. Furthermore, the test method may be used to evaluate reflections of a specified spectral distribution light source (for example, a monochromatic light-emitting diode) by using that source in place of the standard light source.  
4.4 Provisions are made to check for polarization effects of the sample and to record the reflectivity of a standard specimen. These provisions are offered as an option to the tester; it is up to the user or the requiring agency to determine the significance and use of these data.  
4.5 Since the reflections are measured photopically, the results are representative of what the pilot would visually perceive.
SCOPE
1.1 This test method covers a procedure for measuring the reflectivity of transparent materials, hereafter known as specimens. The results are repeatable without specifying a particular brand name of instrumentation.  
1.2 This test method applies to substantially flat parts. Errors in measurement can occur if the parts being measured are not substantially flat.  
1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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
4.1 This test method, when applied to aerospace transparencies of either monolithic glass/plastic or laminated combinations, is a measure of the ability of the transparency to withstand the effects of artificially induced environments. The test applies to configurations employing electrically conductive coatings, and also to uncoated materials.  
4.2 The resistance of the transparent enclosure to environmental effects may vary appreciably depending on the size, geometry, material of construction, coating integrity, coating density, and other factors.
SCOPE
1.1 This test method covers determination of the effects of exposure to thermal shock, condensing humidity, and simulated weather on aerospace transparent enclosures.  
1.2 This test method is not recommended for quality control, nor is it intended to provide a correlation to actual service life.  
1.3 Units—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 Exceptions—Certain inch-pound units are furnished in parentheses (not mandatory) and certain temperatures in Fahrenheit associated with other standards are also furnished.  
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 One of the measures of optical quality of a transparent part is its angular deviation. It is possible that excessive angular deviation, or variations in angular deviation throughout the part, will result in visible distortion of scenes viewed through the part. Angular deviation, its detection, and quantification are of extreme importance in the area of certain aircraft transparency applications, that is, aircraft equipped with Heads-up Displays (HUD). It is possible that HUDs will require stringent control over the optics of the portion of the transparency (windscreen or canopy) which lies between the HUD combining glass and the external environment. Military aircraft equipped with HUDs or similar devices require precise knowledge of the effects of the windscreen or canopy on image position in order to maintain weapons aiming accuracy.  
5.2 Two optical parameters have the effect of changing image position. The first, lateral displacement, is inherent in any transparency which is tilted with respect to the line of sight. The effect of lateral displacement is constant over distance, and seldom exceeds a fraction of an inch. The second parameter, angular deviation, is usually caused by a wedginess or nonparallelism of the transparency surfaces. The effect of angular deviation is related to the tangent of the angle of deviation, thus the magnitude of the image position displacement increases as does the distance between image and transparency. The quantification of angular deviation is then the more critical of the two parameters. Both parameters are illustrated in Fig. X1.1.
SCOPE
1.1 This test method covers measuring the angular deviation of a light ray imposed by transparent parts such as aircraft windscreens and canopies. The results are uncontaminated by the effects of lateral displacement, and it is possible to perform the procedure in a relatively short optical path length. This is not intended as a referee standard. It is one convenient method for measuring angular deviations through transparent windows.  
1.2 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.  
1.3 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
4.1 This test method shall be used to determine the hail impact resistance of windshields for acceptance, design, service, or research purposes. By using this method with the installed windshield angle and velocity of a specific aerospace vehicle, design allowables, criteria, and tolerances can be established for that vehicle's windshield.
SCOPE
1.1 This test method covers the determination of the impact resistance of an aerospace transparent enclosure (windshield, canopy, window, lens cover, etc.), hereinafter called windshield, during hailstorm conditions using simulated hailstones consisting of ice balls molded under tightly controlled conditions. This test shall also be used to meet hail test or performance requirements that are specified by design or contract.  
1.2 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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. For specific hazard statements, see Section 7.  
1.4 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 Significance—This test method provides a means to measure the compatibility of a given transparency through which NVGs are used at night to view outside, nighttime ambient illuminated natural scenes.  
5.2 Use—This test method may be used on any transparent part, including sample coupons. It is primarily intended for use on large, curved, or thick parts that may already be installed (for example, windscreens on aircraft).
SCOPE
1.1 This test method covers apparatuses and procedures that are suitable for measuring the NVG-weighted transmissivity of transparent parts including those that are large, thick, curved, or already installed. This test method is sensitive to transparencies that vary in transmissivity as a function of wavelength.  
1.2 Since the transmissivity (or transmission coefficient) is a ratio of two radiance values, it has no units. The units of radiance recorded in the intermediate steps of this test method are not critical; any recognized units of radiance (for example, watts/m2-str) may be used, as long as it is consistent.2  
1.3 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.  
1.4 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 The optical angular deviation of flat transparent parts, such as aircraft windshields, canopies, cabin windows, and visors, can be measured using these methods. Angular deviation in a windscreen or visor can cause objects to appear at a location different from where they actually are. Variations in angular deviation can be used to characterize distortion and magnification in transparent parts. Also, angular deviation measurements made from the typical right and left eye positions for a windscreen or other transparent medium can be used to determine binocular disparity differences (see Test Method F1181).
SCOPE
1.1 This test method covers the measurement of the optical angular deviation of a light ray imposed by flat transparent parts such as a commercial or military aircraft windshield, canopy, or cabin window.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.2.1 Exceptions—The values given in parentheses are for information only. Also, print size is provided in inch-pound measurements.  
1.3 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.  
1.4 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 With the advent of thick, highly angled aircraft transparencies, multiple imaging has been more frequently cited as an optical problem by pilots. Secondary images (of outside lights), often varying in intensity and displacement across the windscreen, can give the pilot deceptive optical cues of his altitude, velocity, and approach angle, increasing his visual workload. Current specifications for multiple imaging in transparencies are vague and not quantitative. Typical specifications state “multiple imaging shall not be objectionable.”  
5.2 The angular separation of the secondary and primary images has been shown to relate to the pilot's acceptability of the windscreen. This procedure provides a way to quantify angular separation so a more objective evaluation of the transparency can be made. This procedure is of use for research of multiple imaging, quantifying aircrew complaints, or as the basis for windscreen specifications.  
5.3 It is of note that the basic multiple imaging characteristics of a windscreen are determined early in the design phase and are virtually impossible to change after the windscreen has been manufactured. In fact, a perfectly manufactured windscreen has some multiple imaging. For a particular windscreen, caution is advised in the selection of specification criteria for multiple imaging, as inherent multiple imaging characteristics have the potential to vary significantly depending upon windscreen thickness, material, or installation angle. Any tolerances that might be established are advised to allow for inherent multiple imaging characteristics.
SCOPE
1.1 This test method covers measuring the angular separation of secondary images from their respective primary images as viewed from the design eye position of an aircraft transparency. Angular separation is measured at 49 points within a 20 by 20° field of view. This procedure is designed for performance on any aircraft transparency in a laboratory or in the field. However, the procedure is limited to a dark environment. Laboratory measurements are done in a darkened room and field measurements are done at night (preferably between astronomical dusk and astronomical dawn).  
1.2 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 This standard possibly involves hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns 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.  
1.4 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
4.1 The degradation of optical properties of transparent plastics is the single greatest cause for in-service removal and replacement. Some optical qualities are inherent in the geometry, manufacturing process, and materials, and remain relatively unchanged after manufacture, while others are subject to gradual change during exposure to the service environment. Factors having an influence on the crazing of transparent plastics include stress, ultraviolet (UV), moisture, and temperature. Sufficient data has been generated to make it evident that real-world conditioning must be experienced by developmental test specimens, as opposed to testing new unexposed material to determine durability, prior to in-service usage. However, the laboratory simulation of natural weathering, and especially accelerated simulation, is imprecise and correlation of results obtained for different plastics or from using different exposure apparatus must not be attempted until a valid database has been generated for such cross-correlation.
SCOPE
1.1 This test method covers the resistance of transparent plastics exposed to environmental conditioning (accelerated weathering) under a biaxial stress state induced by a pressure cell/test fixture.  
1.2 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 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.  
1.4 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 Diplopia or doubling of vision occurs when there is sufficient binocular disparity present so that the bounds of Panum's area (the area of single vision) is exceeded. This condition arises whenever one object is significantly closer (or farther) than another so that looking at one will cause the image of the other to appear double. This can be easily demonstrated: Close one eye and look at a clock (or other object) on a distant wall. Now place your thumb to one side of the image of the clock. Now open both eyes. If you look at the clock, you should see two thumbs. If you look at your thumb, you should see two clocks.  
5.2 Complaints from pilots flying aircraft equipped with wide field of view head up displays (HUDs), such as the LANTIRN HUD, indicated that they were experiencing discomfort (eye fatigue, headaches, and so forth) or seeing either two targets or two pippers (aiming symbols on the HUD) when using the HUD. Subsequent investigations revealed that the problem arose from the fact that the aircraft transparency and the HUD significantly changed the optical distances of the target and the HUD imagery so that binocular disparity, which exceeded Panum's area was induced. Use of this test method provides a procedure by which the amount of binocular disparity being experienced by a human operator due to the presence of a transparent part in their field of view may be easily and precisely measured.
SCOPE
1.1 This test method covers the amount of binocular disparity that is induced by transparent parts such as aircraft windscreens, canopies, HUD combining glasses, visors, or goggles. This test method may be applied to parts of any size, shape, or thickness, individually or in combination, so as to determine the contribution of each transparent part to the overall binocular disparity present in the total “viewing system” being used by a human operator.  
1.2 This test method represents one of several techniques that are available for measuring binocular disparity, but is the only technique that yields a quantitative figure of merit that can be related to operator visual performance.  
1.3 This test method employs apparatus currently being used in the measurement of optical angular deviation under Test Method F801.  
1.4 The values stated in inches (Imperial units) are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.5 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.  
1.6 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 and windows, can be inspected using this practice, and the amount of optical distortion or deviation can be measured. The measurement shall be checked for acceptability against the specification for the part. The photograph (digital file, print, or negative) shall be maintained as a permanent record of the optical quality of the part.
SCOPE
1.1 This photographic practice determines the optical distortion and deviation of a line of sight through a simple transparent part, such as a commercial aircraft windshield or a cabin window. This practice applies to essentially flat or nearly flat parts moreso than to highly curved materials.  
1.2 Test Method F801 addresses optical deviation (angular deviation), and Test Method F2156 addresses optical distortion using grid line slope. Use these test methods instead of Practice F733 whenever practical.  
1.3 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.  
1.4 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
4.1 Scratches exist on all transparent plastic surfaces. Usually they are very fine scratches from cleaning operations that are not visible when looking through the plastic. Deeper scratches may result from careless cleaning or handling. While these may not be deep enough to affect the structural integrity of the part, their appearance in certain locations may be distracting to the observer looking through the plastic. Therefore, a procedure to define these scratches is useful.
SCOPE
1.1 This test method covers the visual inspection of shallow or superficial scratches on the surface of aerospace transparent plastic materials.  
1.2 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.  
1.3 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
4.1 Scratches exist on all glass surfaces. Often there are very fine scratches from cleaning operations that are not visible when looking through the glass. Visible scratches may be distracting to the observer looking through the transparency. Therefore, a procedure to define the severity of scratches is useful. A visual standard is used because it is not practical to measure the dimensions of the fine scratches in the scope of this test method.
SCOPE
1.1 This test method covers the visual inspection of scratches on the glass surface of aerospace transparent enclosures.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard may involve hazardous materials, operations, and equipment. 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.  
1.4 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
4.1 This practice is useful as a screening basis for acceptance or rejection of transparencies during manufacturing so that units with identifiable flaws will not be carried to final inspection for rejection at that time.  
4.2 This practice may also be employed as a go-no go technique for acceptance or rejection of the finished product.  
4.3 This practice is simple, inexpensive, and effective. Flaws identified by this practice, as with other optical methods, are limited to those that produce temperature gradients when electrically powered. Any other type of flaw, such as minor scratches parallel to the direction of electrical flow, are not detectable.
SCOPE
1.1 This practice covers a standard procedure for detecting flaws in the conductive coating (heater element) by the observation of polarized light patterns.  
1.2 This practice applies to coatings on surfaces of monolithic transparencies as well as to coatings imbedded in laminated structures.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 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. For specific precautionary statements, see Section 6.  
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 Significance—This test method provides a means to measure the transmissivity of parts in the field (already installed on aircraft) and of large, thick or curved parts physically difficult to measure using Test Method D1003.  
5.2 Use—This test method is acceptable for use on any transparent part. It is primarily intended for use on large, curved, or thick parts either pre- or post-installation (for example, windscreens on aircraft).
SCOPE
1.1 This test method describes an apparatus and procedure that is suitable for measuring the transmissivity of large, thick, or curved transparent parts including parts already installed. This test method is limited to transparencies that are relatively neutral with respect to wavelength (not highly colored).  
1.2 Since the transmissivity (transmission coefficient) is a ratio of two luminance values, it has no units. The units of luminance recorded in the intermediate steps of this test method are not critical; any recognized units of luminance (for example, foot-lamberts or candelas per square metre) are acceptable for use, as long as use is consistent.  
1.3 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.  
1.4 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
3.1 This guide is intended for use by material suppliers, aircraft transparent enclosure fabricators, air-frame manufacturers, government agencies, and others that may become involved in the testing of transparency components. These test methods provide data on both individual materials and material combinations commonly utilized in the fabrications of aerospace transparent enclosures comprised of monolithic plastic, coated monolithic plastic or laminated constructions containing plastics.  
3.2 Primary properties and their long term stability are critical to the performance of aerospace transparent enclosures. Property measurement tests define as-manufactured material properties of these materials. Aging procedures provide for exposure of parts or representative sections to environments that induce changes in material properties as determined in property measurement tests. Property measurement tests performed before and after aging exposure provide a means of estimating the potential usable life span of a transparency or to compare the durability of one material with another.  
3.3 When employing these test methods for comparison of materials for weathering effects the user should be aware that the many factors influencing degradation due to weathering vary from one location to another. For direct weathering comparisons, all material(s) shall undergo exposure conditions and property measurements testing at the same time.  
3.4 The test methods listed include those considered critical to the performance of aircraft transparent enclosures. Other test methods to evaluate materials shall also be performed where necessary. Additional test methods are in preparation and will be incorporated. The user is advised to employ the latest revision of any test method.  
3.5 The dominant component of all transparent enclosures is one, or more, rigid transparent sheet(s). The sheet(s) must permit the necessary visibility while providing structural integrity and protecting the ...
SCOPE
1.1 This guide is intended to summarize the standard test methods available on individual and composite materials utilized in fabrication of aerospace plastic transparent enclosures. As such, it is intended to specifically include transparent thermoplastics, transparent elastomers, and reinforced plastics, whether thermoplastic or thermosetting.  
1.2 This guide is intended as an aid in the search for test methods pertinent to Aerospace Plastic Transparent Enclosures. It should be understood that all methods listed may not apply to all enclosures.  
1.3 The standards included refer to the properties or aspects listed in Table 1. The properties or aspects are listed in alphabetical order and the descriptions used are intended to facilitate the search.  
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 The basic material properties obtained from this test method can be used in the control of the quality of interlayers, in the theoretical equations for designing laminated transparencies, and in the evaluation of new interlayers.
SCOPE
1.1 This test method covers the determination of the shear strength and shear modulus of interlayer materials that are restrained by relatively high modulus plies in laminated transparencies. This test method can be used with single or multiple plies of the same interlayer materials.  
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.  
1.3 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.  
1.4 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
4.1 This test method provides a guide for evaluating whether a specific solvent, chemical, or compound is detrimental to a transparent plastic as a result of a manufacturing process, a fabrication operation, or the operational environment. All transparent plastics are susceptible to crazing, though in widely varying degree and from a variety of causes. This test method is intended to allow establishment of the crazing stress when the simultaneous action of both load and a material that will cause crazing is applied, producing non-reversible damage that limits the usage of that transparent plastic in a specific application.
SCOPE
1.1 This test method covers the determination of the critical crazing stress for a transparent plastic material when exposed to a specific solvent, chemical, or compound at a specific temperature.  
1.2 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.  
1.3 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
3.1 This guide is intended for use by material suppliers, aircraft transparent enclosure fabricators, airframe manufacturers, government agencies, and others that may become involved in the testing of transparent interlayer materials. These test methods provide data on both individual interlayer materials and material combinations commonly used in the fabrication of aerospace transparent enclosures and provide a means of evaluating the performance of one interlayer material against another.  
3.2 Primary characteristics and their long-term stability are critical to the performance of an interlayer material. Basic tests define the as-manufactured material characteristics of the interlayer material. Ageing procedures provide for representative exposure to environments that induce changes in material characteristics. Tests performed before and after ageing exposure provide a means of estimating the potential useable life-span of an interlayer material or to compare the durability of one interlayer material with another.  
3.3 When employing these test methods for the comparison of interlayer materials after exposure to selected environmental conditions, the user shall be aware that many factors influencing degradation due to weathering vary from one location and exposure period to another location and exposure period. For direct weathering comparisons, the interlayer materials to be compared shall be subjected to the exposure and have the tests performed at the same time. It is emphasized that the test values obtained under these simultaneously applied conditions are for comparative use and their use as design characteristics shall be made with caution.  
3.4 The test methods listed include those considered critical to the performance of aircraft transparent enclosures. The user is advised to use the latest revision of any test method.
SCOPE
1.1 This guide summarizes the standard test methods available for determining physical and mechanical characteristics of interlayer materials used in multi-ply aerospace transparent enclosures.  
1.2 Interlayer materials are used to laminate glass-to-glass, glass-to-plastic, and plastic-to-plastic. Interlayer materials are basically transparent adhesives with high-quality optical properties. They can also serve as an energy absorbing medium, a fail-safe membrane to contain cockpit pressure and to prevent entry of impact debris; a strain insulator to accommodate different thermal expansion rates of members being laminated and as an adherent to prevent spalling of inner surface ply material fragments. The relative importance of an interlayer characteristic will be a function of the prime use it serves in its particular application.  
1.3 This guide, as a summary of various methods in Section 2, is intended to facilitate the selection of tests that can be applied to interlayer materials.  
1.4 The test methods listed are for use in determining basic design characteristics and in assuring lot-to-lot uniformity of the materials being tested except as noted in 3.3.  
1.5 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.  
1.6 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
4.1 Prisms are useful tools for viewing areas otherwise obstructed or hidden from normal viewing. For example, transparency bolt holes, voids, and delaminations that are covered by edge strips or frames can be seen through a prism. The prism, once put against the transparency, with a coupling agent to wet the surfaces, allows viewing of the area below where the prism is placed.
SCOPE
1.1 Aerospace transparencies undergo high stresses induced by flight, environmental, or other factors. The transparency attachment points are especially subject to fatigue. These areas of fatigue are often obstructed or hidden from normal inspection. An inspector, following the techniques described in this practice, shall use a prism to view damage located near transparency bolt holes, voids, and delamination that are hidden by edge strips or frames.  
1.2 The purpose of this practice is to provide acceptable methods for performing prism inspections of transparent materials with specific emphasis on aircraft windscreens and canopies. Caveats and lessons learned from experience are included to assist authors in writing tailored inspection instructions for specific applications.  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.  
1.4 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.
SCOPE
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 and health 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
4.1 Plastic materials, when used as transparencies, covers, or enclosures, are subject to wiping, cleaning, or other types of rubbing actions that cause abrasion. It is the intent of this test method to provide a means of estimating the resistance of such materials to this type and degree of abrasion.
SCOPE
1.1 This test method determines the resistance of transparent plastics and transparent coatings utilized in windows or viewing ports, to surface abrasion using oscillating sand.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.2.1 Exception—The inch-pound units in parentheses are provided for information only.  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.  
1.4 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 This practice is applicable for qualitatively evaluating coated and uncoated monolithic polycarbonate sheet material, for monitoring process control, for screening studies, and as an aid in the prediction of hardware performance when exposed to impact service conditions.  
5.2 A limitation of Type A specimen testing is that a thick sheet may not fail since the available impact energy is limited by the maximum drop height and falling weight capacity of the test apparatus. Use Specimen Type A for material less than 12.7 mm (0.50 in.) thick.  
5.3 Within the range of drop heights of this system, tests employing different velocities are not expected to produce different results. However, for a given series of tests, the drop height should be held constant so that velocity of impact (strain rate) will not be a variable.  
5.4 As the polycarbonate specimen undergoes large plastic deformation under impact, the down (opposite impact) side is under tensile loading and most influential in initiating failure. For that reason, polycarbonate sheet coated on one side should be tested with the coated side down.  
5.5 Direct comparison of specimen Type A and specimen Type B test results should not be attempted. For test programs that will require the comparison of interlaboratory test results the specimen type and the approximate drop height must be specified.  
5.6 Monolithic polycarbonate sheet is notch sensitive. Data obtained from other test methods, particularly notched Izod/Charpy test results, and extremely high- or low-strain rate test results, should not be compared directly to data obtained from this method. It is noted that Type A specimens, free of flaws, have not experienced the characteristic ductile-to-brittle transition between thin, less than 3.18 mm (1/8 in.), and thick, greater than 7.94 mm (5/16 in.), sheet as reflected by other test methods.
SCOPE
1.1 This test method covers the determination of the energy required to initiate failure in monolithic polycarbonate sheet material under specified conditions of impact using a free falling weight.  
1.2 Two specimen types are defined as follows:  
1.2.1 Type A consists of a flat plate test specimen and employs a clamped ring support.  
1.2.2 Type B consists of a simply supported three-point loaded beam specimen (Fig. 1) for use with material which can not be failed using the Type A specimen. For a maximum drop height of 6.096 m (20 ft) and a maximum drop weight of 22.68 kg (50 lb), virgin polycarbonate greater than 12.70 mm (1/2 in.) thick will require use of the Type B specimen.  
Note 1: See also ASTM Methods: D1709, D2444 and D3029.
FIG. 1 Type B Specimen Geometry and Loading  
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 inch-pound units in parentheses are provided 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statement, See Section 7.  
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 At this writing, aerospace quality extruded transparent polycarbonate material is not available in thicknesses greater than 0.5 in. (12.7 mm). When a requirement exists for sheets thicker than 0.5 in. (12.7 mm), two or more sheets are fusion bonded together to form a single sheet of the desired thickness.  
5.2 The structural integrity of the completed transparency depends on the integrity of the fusion bond. This test applies torsional shear loads to measure the structural integrity of the fusion bond. This test method is considered more reliable and more reproducible than shear tests in tension or compression.
SCOPE
1.1 This test method determines the shear yield strength Fsy   and shear ultimate strength Fsu   of fusion bonds in polycarbonate by applying torsional shear loads to the fusion-bond line.  
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.  
1.3 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
4.1 This test method shall be used for: bird impact testing of aircraft crew compartment transparencies and supporting structure to verify the design; compilation of test data for use in verification of future transparency and supporting structure design and analytical methods; and comparative evaluation of materials.
SCOPE
1.1 This test method covers conducting bird impact tests under a standard set of conditions by firing a packaged bird at a stationary transparency mounted in a support structure.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.

SIGNIFICANCE AND USE
4.1 These test methods provide a means to measure quantitatively the bond integrity between the outer layers of the transparency and the interlayer, or to measure the cohesive properties of the interlayer, under various loading conditions.  
4.2 These test methods provide empirical results useful for control purposes, correlation with service results, and as quality control tests for acceptance of production parts.  
4.3 Test results obtained on small, laboratory-size samples shown herein are indicative of full-size part capability, but not necessarily usable for design purposes.
SCOPE
1.1 These test methods cover determination of the bond integrity of transparent laminates. The laminates are usually made of two or more glass or hard plastic sheets held together by an elastomeric material. These test methods are intended to provide a means of determining the strength of the bond between the glass or plastic and the elastomeric interlayer under various mechanical or thermal loading conditions.  
1.2 The test methods appear as follows:    
Test Methods  
Sections  
Test Method A—Flatwise Bond Tensile Strength  
5 – 11  
Test Method B—Interlaminar Shear Strength  
12 – 17  
Test Method C—Creep Rupture  
18 – 25  
Test Method D—Thermal Exposure  
26 – 30  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 Significance—This test method provides a means to measure the compatibility of a given transparency through which NVGs are used at night to view outside, nighttime ambient illuminated natural scenes.  
5.2 Use—This test method may be used on any transparent part, including sample coupons. It is primarily intended for use on large, curved, or thick parts that may already be installed (for example, windscreens on aircraft).
SCOPE
1.1 This test method covers apparatuses and procedures that are suitable for measuring the NVG-weighted transmissivity of transparent parts including those that are large, thick, curved, or already installed. This test method is sensitive to transparencies that vary in transmissivity as a function of wavelength.  
1.2 Since the transmissivity (or transmission coefficient) is a ratio of two radiance values, it has no units. The units of radiance recorded in the intermediate steps of this test method are not critical; any recognized units of radiance (for example, watts/m2-str) may be used, as long as it is consistent.2  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 All materials on exterior aircraft surfaces are subject to abrasion from airborne particles of various sizes and shapes. Transparent materials are particularly vulnerable to abrasion, since their performance is based on their ability to transmit light with a minimal amount of scatter. Scratches, pitting, and coating removal and delamination as a result of abrasion may increase scatter, reduce transmission, and degrade the performance of transparent materials. Visually transparent materials are required for pilot and air crew enclosures, such as canopies, windshields, and viewpoints. Materials transparent in the IR region (8 to 12 μm) are required for tracking, targeting, and navigational instrumentation.  
5.2 This test method is intended to provide a calibrated and repeatable means of determining the relative abrasion resistance of materials and coatings for optical and IR transparent materials and coatings. The test parameters for this test method can be directly related to dust cloud densities and velocities to which transparent materials are exposed in the field.
SCOPE
1.1 This test method covers the resistance of transparent plastics and coatings used in aerospace windscreens, canopies, and viewports to surface erosion as a result of dust impingement. This test method simulates flight through a defined particle cloud environment by means of independent control of particle size, velocity, impact angle, mass loading, and test duration.  
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method, when applied to aerospace transparencies of either monolithic glass/plastic or laminated combinations, is a measure of the ability of the transparency to withstand the effects of artificially induced environments. The test applies to on configurations employing electrically conductive coatings, and also to uncoated materials.  
4.2 The resistance of the transparent enclosure to environmental effects may vary appreciably depending on the size, geometry, material of construction, coating integrity, coating density, and other factors.
SCOPE
1.1 This test method covers determination of the effects of exposure to thermal shock, condensing humidity, and simulated weather on aerospace transparent enclosures.  
1.2 This test method is not recommended for quality control nor is it intended to provide a correlation to actual service life.  
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 Exceptions—Certain inch-pound units are furnished in parentheses (not mandatory) and certain temperatures in Fahrenheit associated with other standards are also furnished.  
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 and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method shall be used to determine the hail impact resistance of windshields for acceptance, design, service, or research purposes. By coupling this method with the installed angle and velocity of a specific aerospace vehicle, design allowables, criteria, and tolerances can be established for that vehicle's windshield.
SCOPE
1.1 This test method covers the determination of the impact resistance of an aerospace transparent enclosure, hereinafter called windshield, during hailstorm conditions using simulated hailstones consisting of ice balls molded under tightly controlled conditions.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements see Section 7.

SIGNIFICANCE AND USE
4.1 Reflections from aircraft transparencies of instrument lights and other cockpit objects have been a concern to many pilots. Attempts to reduce these reflections have been hampered by the lack of a repeatable measurement method and variances in reflection measuring instrumentation.  
4.2 This test method reduces the instrument variations by standardizing the light source, calculation method, and area of specimen surface being measured; a brand of instrumentation is not specified. Since the reflectivity is defined as the ratio of two luminance measurements and does not depend on an absolute measurement, dependence upon the accuracy of the calibration of the measuring instrument is reduced.  
4.3 The test method may be used to objectively compare the reflection characteristics of various transparent materials. Furthermore, the test method may be used to evaluate reflections of a specified spectral distribution light source (for example, a monochromatic light-emitting diode) by using that source in place of the standard light source.  
4.4 Provisions are made to check for polarization effects of the sample and to record the reflectivity of a standard specimen. These provisions are offered as an option to the tester; it is up to the user or the requiring agency to determine the significance and use of these data.  
4.5 Since the reflections are measured photopically, the results are representative of what the pilot would visually perceive.
SCOPE
1.1 This test method covers a procedure for measuring the reflectivity of transparent materials, hereafter known as specimens. The results are repeatable without specifying a particular brand name of instrumentation.  
1.2 This test method applies to substantially flat parts. Errors in measurement can occur if the parts being measured are not substantially flat.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 One of the measures of optical quality of a transparent part is its angular deviation. It is possible that excessive angular deviation, or variations in angular deviation throughout the part, will result in visible distortion of scenes viewed through the part. Angular deviation, its detection, and quantification are of extreme importance in the area of certain aircraft transparency applications, that is, aircraft equipped with Heads-up Displays (HUD). It is possible that HUDs will require stringent control over the optics of the portion of the transparency (windscreen or canopy) which lies between the HUD combining glass and the external environment. Military aircraft equipped with HUDs or similar devices require precise knowledge of the effects of the windscreen or canopy on image position in order to maintain weapons aiming accuracy.  
5.2 Two optical parameters have the effect of changing image position. The first, lateral displacement, is inherent in any transparency which is tilted with respect to the line of sight. The effect of lateral displacement is constant over distance, and seldom exceeds a fraction of an inch. The second parameter, angular deviation, is usually caused by a wedginess or nonparallelism of the transparency surfaces. The effect of angular deviation is related to the tangent of the angle of deviation, thus the magnitude of the image position displacement increases as does the distance between image and transparency. The quantification of angular deviation is then the more critical of the two parameters.
SCOPE
1.1 This test method covers measuring the angular deviation of a light ray imposed by transparent parts such as aircraft windscreens and canopies. The results are uncontaminated by the effects of lateral displacement, and it is possible to perform the procedure in a relatively short optical path length. This is not intended as a referee standard. It is one convenient method for measuring angular deviations through transparent windows.  
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 The optical angular deviation of flat transparent parts, such as aircraft windshields, canopies, cabin windows, and visors, can be measured using these methods. Angular deviation in a windscreen or visor can cause objects to appear at a location different from where they actually are. Variations in angular deviation can be used to characterize distortion and magnification in transparent parts. Also, angular deviation measurements made from the typical right and left eye positions for a windscreen or other transparent medium can be used to determine binocular disparity differences (see Test Method F1181).
SCOPE
1.1 This test method covers the measurement of the optical angular deviation of a light ray imposed by flat transparent parts such as a commercial or military aircraft windshield, canopy, or cabin window.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.2.1 Exceptions—The values given in parentheses are for information only. Also, print size is provided in inch-pound measurements.  
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.

SCOPE
1.1 These definitions cover generic optical terms which appear in one of more standards relating to aerospace transparent materials and enclosures.  
1.2 The definitions cover, in most cases, special meanings used in the transparency industry. No attempt has been made to include common meanings of the same terms as used outside of the transparency industry.  
1.3 Definitions included have, in general, been approved as standard.

SIGNIFICANCE AND USE
5.1 With the advent of thick, highly angled aircraft transparencies, multiple imaging has been more frequently cited as an optical problem by pilots. Secondary images (of outside lights), often varying in intensity and displacement across the windscreen, can give the pilot deceptive optical cues of his altitude, velocity, and approach angle, increasing his visual workload. Current specifications for multiple imaging in transparencies are vague and not quantitative. Typical specifications state “multiple imaging shall not be objectionable.”  
5.2 The angular separation of the secondary and primary images has been shown to relate to the pilot's acceptability of the windscreen. This procedure provides a way to quantify angular separation so a more objective evaluation of the transparency can be made. This procedure is of use for research of multiple imaging, quantifying aircrew complaints, or as the basis for windscreen specifications.  
5.3 It is of note that the basic multiple imaging characteristics of a windscreen are determined early in the design phase and are virtually impossible to change after the windscreen has been manufactured. In fact, a perfectly manufactured windscreen has some multiple imaging. For a particular windscreen, caution is advised in the selection of specification criteria for multiple imaging, as inherent multiple imaging characteristics have the potential to vary significantly depending upon windscreen thickness, material, or installation angle. Any tolerances that might be established are advised to allow for inherent multiple imaging characteristics.
SCOPE
1.1 This test method covers measuring the angular separation of secondary images from their respective primary images as viewed from the design eye position of an aircraft transparency. Angular separation is measured at 49 points within a 20 by 20° field of view. This procedure is designed for performance on any aircraft transparency in a laboratory or in the field. However, the procedure is limited to a dark environment. Laboratory measurements are done in a darkened room and field measurements are done at night.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.2.1 Exception—The values in parentheses are for information only.  
1.3 This standard possibly involves hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 Diplopia or doubling of vision occurs when there is sufficient binocular disparity present so that the bounds of Panum's area (the area of single vision) is exceeded. This condition arises whenever one object is significantly closer (or farther) than another so that looking at one will cause the image of the other to appear double. This can be easily demonstrated: Close one eye and look at a clock (or other object) on a distant wall. Now place your thumb to one side of the image of the clock. Now open both eyes. If you look at the clock, you should see two thumbs. If you look at your thumb, you should see two clocks.  
5.2 Complaints from pilots flying aircraft equipped with wide field of view head up displays (HUDs) such as the LANTIRN HUD indicated that they were experiencing discomfort (eye fatigue, headaches, and so forth.) or seeing either two targets or two pippers (aiming symbols on the HUD) when using the HUD. Subsequent investigations revealed that the problem arose from the fact that the aircraft transparency and the HUD significantly changed the optical distances of the target and the HUD imagery so that binocular disparity, which exceeded Panum's area was induced. Use of this test method provides a procedure by which the amount of binocular disparity being experienced by a human operator due to the presence of a transparent part in his field of view may be easily and precisely measured.
SCOPE
1.1 This test method covers the amount of binocular disparity that is induced by transparent parts such as aircraft windscreens, canopies, HUD combining glasses, visors, or goggles. This test method may be applied to parts of any size, shape, or thickness, individually or in combination, so as to determine the contribution of each transparent part to the overall binocular disparity present in the total “viewing system” being used by a human operator.  
1.2 This test method represents one of several techniques that are available for measuring binocular disparity, but is the only technique that yields a quantitative figure of merit that can be related to operator visual performance.  
1.3 This test method employs apparatus currently being used in the measurement of optical angular deviation under Method F801.  
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.