Laser_Eye_Protection_-_DRAFT_LEP_Spec_3_Mar_2015_(FBO).pdf

PMA202-11001/R-0

DRAFT

DEPARTMENT OF THE NAVY

PROGRAM EXECUTIVE OFFICE PMA202

NAVAL AIR SYSTEMS COMMAND

PATUXENT RIVER, MD 20670

PERFORMANCE SPECIFICATION

FOR

MULTIPLE WAVELENGTH

AIRCREW LASER EYE PROTECTION

THREAT SPECTACLES

DISTRIBUTION STATEMENT D: Distribution limited to DoD and DoD Contractors only; Critical Technology: To protect information and technical data that advance current technology or describe new technology in an area of significant or potentially significant military application or that relate to a specific military deficiency of a potential adversary.

Information of this type may be classified or unclassified; when unclassified, it is export-controlled and subject to the provisions of DOD Directive 5230.25. Other requests for this document shall be referred to Commander, Naval Air Systems Command (PMA202), 21491 Great Mills Road, Lexington Park, MD 20653-1394.

APPROVED: _______________________________ DATE: ______________

TITLE: PROGRAM MANAGER

TITLE: SYSTEMS ENGINEERING DEPT. (AIR-4.1)

TITLE: LOGISTICS MANAGEMENT INTEGRATION (AIR-6.6)

ii

TABLE OF CONTENTS

1.0 SCOPE

1.1 SCOPE

1.2 THREAT

2.0 APPLICABLE DOCUMENTS

2.1 GENERAL

2.2 GOVERNMENT DOCUMENTS

2.2.1 Specifications, standards, and handbooks

2.3 NON-GOVERNMENT PUBLICATIONS

2.4 ORDER OF PRECEDENCE

3.0 PERFORMANCE REQUIREMENTS

3.1 GENERAL

3.2 QUALIFICATION INSPECTION

3.3 DESIGN

3.3.1 Anthropometrics

3.3.2 Frame color

3.3.3 Prescription eyewear compatibility

3.3.4 Weight

3.3.5 Diagnostics

3.4 LASER PROTECTION

3.5 COMPATIBILITY

3.5.1 Physical compatibility

3.5.2 Visual compatibility

3.6 OPTICAL QUALITY

3.6.1 Vertical prismatic deviation

3.6.2 Horizontal prismatic deviation

3.6.3 Spherical and cylindrical power

3.6.4 Optical distortion

3.6.5 Haze

3.7 LUMINOUS TRANSMITTANCE

3.7.1 Photopic luminous transmission

3.7.2 Scotopic luminous transmission

3.7.3 P43 transmission

3.7.4 Erythemal ultraviolet transmittance

3.7.5 Red edge visibility

3.8 ENVIRONMENTAL

3.8.1 Solar radiation

3.8.2 Laser saturation

3.8.3 High temperature

3.8.4 Low temperature

3.8.5 Temperature shock

3.8.6 Humidity

3.8.7 Salt fog

3.8.8 Chemical

3.9 MECHANICAL

3.9.1 Abrasion resistance

3.9.2 Lens coating adhesion resistance

3.9.3 Lens impact resistance

3.9.4 Prescription lens carrier impact resistance

3.9.5 Lens fit

3.9.6 Frame

iii

3.9.7 Protective carrying case

3.10 IDENTIFICATION OF PRODUCT

3.10.1 Spectacle identification

3.10.2 Protective case identification

3.11 WORKMANSHIP

3.11.1 Defects in viewing surface

3.11.2 Frame defects

3.12 MAINTAINABILITY

3.12.1 Maintenance

3.12.2 Mean time to repair (MTTR)

3.13 RELIABILITY OF LEP SPECTACLE

4.0 VERIFICATION

4.1 CLASSIFICATION OF INSPECTIONS

4.2 QUALIFICATION INSPECTION

4.3 CONFORMANCE INSPECTION

4.4 INSPECTION LOT

4.5 DESIGN VERIFICATION

4.5.1 Prescription eyewear compatibility

4.5.2 Weight

4.6 LASER PROTECTION

4.6.1 Reflective filtering technologies

4.6.2 Absorptive filtering technologies

4.7 COMPATIBILITY

4.7.1 Physical compatibility

4.7.2 Visual compatibility

4.8 OPTICAL QUALITY

4.8.1 Vertical prismatic deviation

4.8.2 Horizontal prismatic deviation

4.8.3 Spherical and cylindrical power

4.8.4 Optical distortion

4.8.5 Haze

4.9 LUMINOUS TRANSMITTANCE

4.9.1 Photopic luminous transmittance

4.9.2 Scotopic luminous transmittance

4.9.3 P43 transmittance

4.9.4 Erythemal ultraviolet transmittance

4.9.5 Red edge visibility

4.10 ENVIRONMENTAL TESTS

4.10.1 Solar radiation

4.10.2 Laser saturation

4.10.3 High temperature

4.10.4 Low temperature

4.10.5 Temperature shock

4.10.6 Humidity

4.10.7 Salt fog

4.10.8 Chemical

4.11 MECHANICAL

4.11.1 Taber abrasion resistance

4.11.2 Bayer abrasion resistance

4.11.3 Lens coating adhesion resistance

4.11.4 Impact resistance

4.11.5 Prescription lens carrier impact resistance

4.11.6 Lens fit

4.11.7 Frame ductility

4.11.8 Frame adhesion of plating

iv

4.12 PROTECTIVE CARRYING CASE

4.12.1 Transit drop

4.12.2 Crush resistance of carrying case

4.12.3 Case lining

4.13 WORKMANSHIP

4.13.1 Defects in viewing surface

4.13.2 Frame defects

4.14 MAINTAINABILITY

4.14.1 Maintenance

4.14.2 Mean Time to Repair (MTTR)

4.15 RELIABILITY OF LEP

5.0 PACKAGING

5.1 PACKAGING

6.0 NOTES

6.1 PARENTHETICAL NOTE

6.2 INTENDED USE

6.3 ACQUISITION REQUIREMENTS

6.4 RESERVED

6.5 DEFINITIONS

6.5.1 Corrosion

6.5.2 Cosmetic defects

6.5.3 Interfere

6.5.4 Red edge

6.5.5 Safety zone

6.5.6 "as worn"

6.5.7 Base in

6.5.8 Base out

6.5.9 Base up

6.5.10 Base down

6.6 LESSONS LEARNED

6.7 GOVERNMENT-FURNISHED AND GOVERNMENT-LOANED PROPERTY

6.8 RESERVED

6.9 CLASSIFIED INFORMATION REQUEST

6.10 CUSTODIANS AND PREPARING ACTIVITY

APPENDIX A

A.1 SCOPE

A.2 APPLICABLE DOCUMENTS

A.3 LUMINOUS TRANSMITTANCE

6.10.1 Design eye point

A.4 PHOTOPIC AND SCOTOPIC TRANSMITTANCE CALCULATION

APPENDIX B

B.1 SCOPE

B.2 EQUIPMENT LIST

B.3 TEST METHODS

APPENDIX C – Classified Appendix v

LIST OF FIGURES

FIGURE 1. TEST POINT MERIDIANS AND NOMENCLATURE

FIGURE 2. LENS TEST LOCATIONS

FIGURE A-1. NORMALIZED WEIGHTING FACTORS USED TO DETERMINE PHOTOPIC, SCOTOPIC, AND P43

TRANSMITTANCE

LIST OF TABLES

TABLE I. DESIGN PARAMETERS

TABLE II. QUALIFICATION - VERIFICATION CROSS REFERENCE

TABLE III. CONFORMANCE – VERIFICATION CROSS REFERENCE

TABLE IV. INSPECTION LOT – VERIFICATION CROSS REFERENCE

TABLE V. TEST SUBJECT POPULATION BREAKDOWN

TABLE VI. EXPOSURE LEVELS FOR LASER SATURATION TESTING

TABLE VII - SERVICE LIFE TESTS

TABLE A-I. EXAMPLES OF PASS OR FAILED TRANSMITTANCE IMBALANCE VALUES

TABLE A-II. LUMINOUS AND P43 TRANSMITTANCE DATA

TABLE B- I. LASER EYE PROTECTION INTERFACE CONTROL REQUIREMENTS

LIST OF EQUATIONS

EQUATION A-1. WEIGHTING AVERAGE FOR LUMINOUS AND P43 TRANSMITTANCE ACCEPTABILITY FOR

MULTI-WAVE LASER EYE PROTECTION

vi

Document History Log

Status

(Baseline/

Revision/

Canceled)

Document

Revision Effective Date Description

DRAFT DRAFT

PMA202-11001/R-0

DRAFT

1.0 SCOPE

1.1 Scope.

This performance specification details the functional requirements and technical characteristics of aircrew laser eye protection (LEP) spectacles. The LEP spectacles are to protect against exposure to multiple, fixed wavelength laser radiation. The LEP spectacles are to be used by all fixed and rotary wing aircrew in day and night, combat and training missions.

1.2 Threat.

Specific threat wavelengths and optical density (OD) requirements are contained in the classified, Appendix C. Only persons with a “need-to-know” will be authorized access.

Information on requesting access is included in 6.9.

2.0 APPLICABLE DOCUMENTS

2.1 General.

The documents listed in this section are specified in Sections 3 or 4 of this specification. This section may include documents that are mentioned in other sections of this specification, recommended for additional information, or as examples. While every effort has been made to ensure the completeness of this list, users are cautioned that they must meet all specified requirements of documents cited in Sections 3 and 4 of this specification, whether or not they are listed as applicable documents.

2.2 Government documents.

2.2.1 Specifications, standards, and handbooks.

The following specifications, standards, and handbooks of the exact revision listed below form a part of this specification to the extent specified herein.

DEPARTMENT OF DEFENSE STANDARDS

MIL-DTL-43511 - Detail Specification, Visors Flyers Helmet, Polycarbonate

MIL-STD-129 - Marking for Shipment and Storage

MIL-STD-130 - Identification Marking of US Military Property

MIL-STD-810G - Environmental Engineering Considerations and

Laboratory Tests

(Copies of these documents are available online at http://quicksearch.dla.mil/ or from the Standardization

Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)

2.3 Non-Government publications.

The following documents of the exact revision listed below form a part of this document to the extent specified herein.

AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI)

http://quicksearch.dla.mil/

ANSI/ASQC Z-1.4 - American National Standard Sampling Procedures &

Tables for Inspection by Attributes

ANSI Z80.1

Ophthalmic – Prescription Ophthalmic Lenses –

Recommendations

ANSI/ISEA Z87.1-2010 - Occupational and Educational Personal Eye and Face

Protection Devices

ANSI Z136.7 - Testing and labeling of Laser Eye Protection

Equipment (Copies of these documents are available from www.ansi.org )

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM-D412 - Standard Test Methods for Vulcanized Rubber and

Thermoplastic Rubbers and Thermoplastic Elastomers

- Tension (DoD adopted)

ASTM-D1003 - Standard Test Methods for Haze and Luminous

Transmittance of Transparent Plastics

ASTM-D1044 - Standard Test Method for Resistance of Transparent

Plastics to Surface Abrasion

ASTM-D1415 - Standard Test Method for Rubber Property -

International Hardness. (DoD adopted)

ASTM-D3359 - Standard Test Method for Measuring Adhesion by

Tape Test

ASTM-F735 - Abrasion Resistance of Transparent Plastics and

Coatings Using the Oscillating Sand Method (Copies of these documents are available from www.astm.org or by application from the American

Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.)

OTHER NON-GOVERNMENT PUBLICATIONS

Farnsworth, D., “The Farnsworth-Munsell 100 Hue and Dichotomous Tests for Color

Vision,” Journal of the Optical Society of America, Vol 33, 1943, pp. 568–578.

Copies of these documents can be found at The Optical Society’s (OSA) website http://www.opticsinfobase.org/ or by application from the OSA at 2010 Massachusetts Ave., N.W.

Washington, D.C. 20036-1012 USA

COMMERCIAL ITEM DESCRIPTIONS

A-A-113D - Tape, Pressure Sensitive Adhesive

(Copies of these documents are available online at http://quicksearch.dla.mil/ or from the Standardization

Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)

http://www.ansi.org/ http://www.astm.org/ http://www.opticsinfobase.org/ http://quicksearch.dla.mil/

2.4 Order of precedence.

In the event of a conflict between the text of this specification and the references cited herein, the text of this specification takes precedence. Nothing in this specification, however, supersedes applicable laws and regulations, unless a specific exemption has been obtained.

3.0 PERFORMANCE REQUIREMENTS

3.1 General.

Unless otherwise noted, all performance requirements detailed herein shall apply to the LEP

(lens and frame assembly). When requirements address subordinate components, such as lens, frame, prescription component, or protective carrying case, it will be indicated.

3.2 Qualification inspection.

When specified (see 6.3), a sample shall be subjected to qualification inspection.

3.3 Design.

3.3.1 Anthropometrics

The design and dimensions of the LEP shall accommodate the anthropometric dimensions listed in TABLE I.

TABLE I. Design Parameters

Design Parameter for Spectacles Limiting Value

Maximum pupil diameter 7 mm

Maximum eye rotation ±35º

Distance in front of canthus 9 mm

Average distance from pupil plane to center of rotation of line of sight

11.3 mm

Vertical Fit Tolerance 4 mm

Horizontal Fit Tolerance 6.5 mm

Eye Relief 12-15 mm th percentile Interpupillary Distance 56.5 mm th percentile Interpupillary Distance 69.5 mm

Average Interpupillary Distance 62.5 mm th percentile Head Breadth 140 mm th percentile Head Breadth 161 mm

Average Head Breadth 150 mm

3.3.2 Frame color.

The color of the frame shall be matte black.

3.3.3 Prescription eyewear.

The LEP shall physically and optically support a prescription (Rx) eyewear component with a range of ± 4 diopters of sphere and 0 to -2 diopters of cylinder. The LEP spectacle, with prescription, shall meet all requirements in this specification, except for 3.4, 3.5.1.2, 3.6 and 3.7.

The LEP spectacle prescription solution shall meet the optical requirements in Section 5 of ANSI

Z80.1. The Rx component shall not require the use of tools for installation or removal. Rx component shall have a means of retention (i.e., locking mechanism) that requires intentional action to remove. All lens surfaces, both Rx and LEP shall have the ability to be wiped clean in flight.

3.3.4 Weight.

The LEP spectacle without prescription shall weigh no more than 25g. The LEP spectacle, with prescription component of +4.0 diopters of sphere installed, shall weigh no more than 40g.

3.3.5 Diagnostics.

Unserviceable conditions, such as scratches, delaminating, laser burns, which could degrade LEP performance, shall be identifiable in the field by visual inspection without the need for specialized test equipment.

3.4 Laser protection.

The LEP spectacle shall provide protection at the required optical densities and wavelengths specified in Appendix C, throughout the entire safety zone. Safety zone geometry shall be determined in accordance with ANSI Z136.7.

3.5 Compatibility.

3.5.1 Physical compatibility.

The LEP spectacle shall be physically compatible and not interfere with the operation and use of all equipment listed in Table B-1-. No optical devices (Lens, Visor, Eye piece of NVD, Display monocle, etc…) shall come into contact with one another.

3.5.1.1 Fit and comfort.

The LEP spectacle shall not cause hot spots, pressure points, or slippage on greater than five percent of the aircrew to the extent that it prevents mission completion over a three hour consecutive time period.

3.5.1.2 Fitting time.

The initial fit time shall be no greater than 20 minutes. Fitting shall be defined as the process of determining proper fit and pupil alignment.

3.5.2 Visual compatibility.

The LEP spectacle shall, in all lighting conditions, be visually and spectrally compatible with all aircraft cockpit displays and lighting, canopies and windscreens, all airfield lighting systems as well as all helmet mounted displays, visors, and night vision systems listed in Table B-I in

Appendix B. The LEP spectacle shall allow for display readability so as to not degrade mission performance. The LEP spectacles shall not degrade the user’s ability to distinguish terrain colors and geological features.

3.5.2.1 Visual acuity

Distance Visual Acuity Shall not be less than 20/20 when LEP spectacles are worn. Near Visual

Acuity shall not be less than 20/40 when LEP spectacles are worn.

3.5.2.2 Eye strain.

The LEP spectacle shall not cause eye strain, visual fatigue, or optical distortion on more than 5 percent of aircrew, to the extent that it interferes with the mission completion during missions of no less than three hours.

3.5.2.3 Farnsworth Munsell Hue-100.

The LEP delta total error score shall be no more than 50 when tested as specified in 4.7.2.4.

3.5.2.4 Anti-reflection.

The LEP spectacle shall not exhibit extraneous reflections (ghost images) in the backward direction such that it degrades mission performance.

3.5.2.5 Field of view.

The LEP spectacle shall allow for adequate field of view (FOV), including FOV through NVDs and other HMDs, so as to not degrade mission performance.

3.6 Optical quality.

3.6.1 Vertical prismatic deviation.

The vertical prismatic power along the line of sight, through the design eye point shall not exceed ±0.18 prism diopters. The imbalance of vertical prismatic power between the left and right lens, along the lines of sight, through the design eye points, shall not exceed 0.125 prism diopters. For off-axis points identified in Figure 2 vertical prismatic imbalance shall not exceed

±0.33 prism diopters.

3.6.2 Horizontal prismatic deviation.

The horizontal prismatic power along the line of sight, through the design eye point, shall not exceed 0.18 prism diopters, BASE IN, and shall not exceed 0.25 prism diopters, BASE OUT.

The imbalance of horizontal prismatic power between the left and right lens, along the lines of sight, through the design eye points shall not exceed 0.125 prism diopters, BASE IN, or 0.25 prism diopters, BASE OUT. For off-axis points identified in Figure 2 horizontal prismatic imbalance shall not exceed ±0.33 prism diopters.

3.6.3 Spherical and cylindrical power.

The spherical and cylindrical power shall not exceed ±0.125 diopters or differ by more than

0.125 diopters between left and right lens.

3.6.4 Optical distortion.

Each lens of the assembled LEP shall conform to one of the five acceptable fringe patterns as depicted in figure titled, “Visors optical distortion standards", of MIL-DTL-43511 throughout the viewing area.

3.6.5 Haze.

Haze shall be no greater than 3.00 percent.

3.7 Luminous transmittance.

In addition to the transmission requirements herein, the luminous transmission values [PLT, SLT, P43] of the left vs. right lens shall not differ by more than 10 percent of the higher of the two values.

3.7.1 Photopic luminous transmission.

The LEP photopic luminous transmittance (PLT) shall be no less than 60 percent.

3.7.2 Scotopic luminous transmission.

The LEP scotopic luminous transmission (SLT) shall be no less than 10 percent.

3.7.3 P43 transmission.

The P43 transmittance shall be no less than 10percent.

3.7.4 Erythemal ultraviolet transmittance.

The erythemal ultraviolet transmittance of the lens shall be no greater than one percent.

3.7.5 Red edge visibility.

The wavelength at which the spectral transmittance initially drops below one percent, scanning from shorter to longer wavelengths, shall be no less than 650 nm.

3.8 Environmental.

The LEP spectacle shall meet the requirements of this specification following exposure to the requirements listed in 3.8.

3.8.1 Solar radiation.

The LEP spectacle shall meet the requirements of this specification following exposure to solar radiation up to 1120W/m at 49± 2° C (120° F) for 80 hours (4 cycles).

3.8.2 Laser saturation.

Lenses that employ an absorptive material shall not exhibit temporary or permanent reductions in laser protection, for the discrete wavelengths specified in the Appendix C.

3.8.3 High temperature.

The LEP spectacle shall be exposed to a high temperature of 71°C ±2° (160°F) while in the protective case. Following this exposure, the LEP spectacle shall meet the requirements of this specification.

3.8.4 Low temperature.

Following low temperature exposure of -54°C ±2° (-65°F), the LEP spectacle, while in protective case, shall meet the requirements of this specification.

3.8.5 Temperature shock.

Following exposure to a temperature transition of 71°C ±2°C (160°F) to standard ambient conditions, IAW MIL-STD-810G, and a temperature transition of -54°C ±2° (-65°F) to standard ambient conditions, the LEP spectacle shall meet the requirements of this specification.

3.8.6 Humidity.

Following exposure to humidity, IAW MIL-STD-810G, Method 507.5, Procedure II, tailored for a maximum temperature of 52°C (126°F), the LEP spectacle shall meet the requirements of this specification

3.8.7 Salt fog.

Following exposure to salt fog, the LEP spectacle shall meet the requirements of this specification. After exposure to salt fog, the LEP spectacle shall not exhibit any corrosion.

3.8.8 Chemical.

The LEP lens shall continue to meet the requirements of this specification following exposure to the listed chemicals, as specified in 4.10.8.

a. Insect repellent, controlled release (98.1% DEET)

b. JP5 aircraft turbine fuel

c. JP8 aircraft turbine fuel, kerosene type

d. Aircraft lube oil, turbine engine, synthetic base

e. Aircraft hydraulic fluid, petroleum base

f. Aircraft hydraulic fluid, fire-resistant, synthetic base

g. Degreasing solvent, type I (mineral spirits)

h. Cleaning compound, turbine engine gas path, 20% solution

i. JP4 aircraft turbine fuel

j. Anti-fog compound

3.9 Mechanical.

3.9.1 Abrasion resistance.

3.9.1.1 Taber abrasion resistance.

The LEP lens haze shall not increase by more than two percent or transmittance decrease by more than four percent after being subjected to the Taber abrasion test, as specified in 4.11.1.

3.9.1.2 Bayer abrasion resistance.

The LEP lens Bayer ratio shall exceed a value of 4.0 or higher after being subjected to the Bayer abrasion test, as specified in 4.11.2.

3.9.2 Lens coating adhesion resistance.

Any lens coating on the outer surface shall not be damaged or removed when subjected to the tape adhesion test in 4.12.3

3.9.3 Lens impact resistance.

Following solar radiation exposure as specified in 4.11.1, the lens shall not fracture into two or more separate pieces, when tested as specified in 4.12.4.

3.9.4 Prescription lens carrier impact resistance.

When tested in accordance with 4.12.5, the complete device shall be capable of resisting an impact from a pointed projectile weighing 500 g (17.6 oz.) dropped from a height of 127 cm

(50.0 in.). The LEP device, with Rx carrier installed, shall remain intact, with no pieces separating from LEP spectacle frame.

3.9.5 Lens fit.

The LEP spectacle shall show no evidence of visible space between the frame and lens.

3.9.6 Frame.

3.9.6.1 Ductility.

The LEP spectacle temple arms shall not break or crack after being subjected to a 45 degree angle bend.

3.9.6.2 Adhesion of plating.

If the LEP frame or temple arm is coated (painted or plated), the adhesion of any layer shall not separate from each other or from the base material.

3.9.7 Protective carrying case.

A protective storage/carrying case shall be provided with each pair of LEP spectacles.

3.9.7.1 Transit drop.

The LEP spectacle carrying case shall remain closed, and protect the LEP spectacle from any damage, when dropped from a height of 5 meters.

3.9.7.2 Crush resistance.

The carrying case shall prevent damage or degradation to the LEP spectacle when a 13.3kg (29 pounds) force is applied as specified in 4.13.2.

3.9.7.3 Case lining.

The inside surface of the LEP spectacle carrying case shall be lined with a non-shedding material. The case lining shall not scratch the LEP spectacle lens.

3.10 Identification of product.

3.10.1 Spectacle identification.

The LEP spectacle shall be identified in accordance with MIL-STD-130 by type designator and serial number engraved or etched on each frame, part number on inside of right temple arm and bridge size on inside of nose bridge area if multiple sizes, to allow tracking from the time of final assembly until disposal. The identification marking shall not interfere with the optical or protective properties or its mounting assembly. The identification marking shall not cause the device to be classified.

3.10.2 Protective case identification.

The carrying case shall display the following information inside:

SPECTACLES, AVIATOR’S

LASER EYE PROTECTION,

XXX-XX

PMA202-11001/R-0

IMPACT RESISTANT – NOT SAFETY GLASSES

MANUFACTURER’S IDENTIFICATION

CONTRACT OR ORDER NUMBER

3.11 Workmanship.

3.11.1 Defects in viewing surface.

The LEP spectacle lens shall not contain any cosmetic defects.

3.11.2 Frame defects.

The frame shall be free of mechanical damage or warping in any region. There shall be no burrs or sharp edges..

3.12 Maintainability.

3.12.1 Maintenance

If item is repairable, maintenance shall be designed to be performed by Fleet users utilizing common shop tools requiring no special training, additional skills, or additional manpower for storage, operation and maintenance of the spectacles beyond basic skills of a USN/USMC

Aircrew Survival Technician Rating. These maintenance requirements shall include, but are not limited to cleaning, inspection, alignment, and repair (if applicable).

3.12.2 Mean time to repair (MTTR).

If the LEP is a repairable, the LEP shall demonstrate a Mean Time to Repair (MTTR) of 0.25 hours or less. MTTR is determined by dividing the sum of elapsed maintenance time to perform all repair tasks by the sum of all failures. No repair task shall take more than 0.5 hours. The

LEP shall be designed to be maintained by Navy and Marine Corps Organizational Level

Maintainers.

3.13 Reliability of LEP spectacle

The LEP spectacle shall meet the requirements of this specification for service life of at least five years with no defects. Service life starts when the Government takes possession of the LEP.

4.0 VERIFICATION

4.1 Classification of inspections.

The inspection requirements specified herein are classified as follows:

a. Qualification Inspection (4.2)

b. Conformance Inspection (4.3)

c. Inspection Lot (4.4)

4.2 Qualification inspection.

All assets developed during the engineering, manufacturing and development (EMD) phase of the acquisition process shall be subject to Qualification inspection. Qualification inspection shall include the requirements and verification examinations and tests listed in TABLE II.

TABLE II. Qualification - Verification Cross Reference

(Includes all requirements within this specification. These tests are performed on EDM units.)

Conformance Area / Test Requirement

Paragraph

Verification

Paragraph

Verification Method

In sp ec ti o n

A al y si s

T es t

D em o n st ra ti

Anthropometrics 3.3.1 4.8.1 X X X X

Frame Color 3.3.2 N/A X

Prescription Eyewear

Compatibility

3.3.3 4.6.1 X X X X

Weight 3.3.4 4.5.2 X

Diagnostics 3.3.5 N/A X

Laser Protection 3.4 4.6 X

Physical Compatibility 3.5.1 4.7.1 X X X

Fit and Comfort 3.5.1.1 4.7.1 X X

Fitting Time 3.5.1.2 4.7.1.1 X

Visual Compatibility 3.5.2 4.7.2 X

Visual Acuity 3.5.2.1 4.7.2.1 X

Eye Strain 3.5.2.2 4.7.2.2 X X

Farnsworth Munsell Hue-100 3.5.2.3 4.7.2.3 X

Anti-Reflection 3.5.2.4 N/A X X

Field of View 3.5.2.5 4.7.2 X

Vertical Prismatic Deviation 3.6.1 4.8, 4.8.1 X

Horizontal Prismatic Deviation 3.6.2 4.8, 4.8.2 X

(Includes all requirements within this specification. These tests are performed on EDM units.)

Conformance Area / Test Requirement

Paragraph

Verification

Paragraph

Verification Method

In sp ec ti al y si s

T o n st ra ti

Spherical and Cylindrical Power 3.6.3 4.8, 4.8.3 X

Optical Distortion 3.6.4 4.8, 4.8.4 X

Haze 3.6.5 4.8, 4.8.5 X

Luminous Transmittance 3.7 4.9 X

Photopic Luminous Transmission 3.7.1 4.9.1 X

Scotopic Luminous Transmission 3.7.2 4.9.2 X

P43 Transmission 3.7.3 4.9.3 X

Erythemal Ultraviolet

Transmittance

3.7.4 4.9.4 X

Red Edge Visibility 3.7.5 4.9.5 X X

Solar Radiation 3.8.1 4.10, 4.10.1 X

Laser Saturation 3.8.2 4.10, 4.10.2 X

High Temperature 3.8.33 4.10.3 X

Low Temperature 3.8.4 4.10.4 X

Temperature Shock 3.8.5 4.10.5 X

Humidity 3.8.6 4.10.6 X

Salt Fog 3.8.7 4.10.7 X

Chemical 3.8.8 4.10.8 X

Taber Abrasion Resistance 3.9.1.1 4.11.1 X

Bayer Abrasion 3.9.1.2 4.11.2 X

Lens Coating Adhesion

Resistance

3.9.2 4.11.3 X

Lens Impact Resistance 3.9.3 4.11.4 X

Prescription Lens Carrier Impact

Resistance

3.9.4 4.11.5

X

Lens Fit 3.9.5 4.11.6 X

Frame Ductility 3.9.6.1 4.11.7 X

Frame Adhesion of Plating 3.9.6.2 4.11.8 X

Transit Drop 3.9.7.1 4.12.1 X

Crush Resistance 3.9.7.2 4.12.2 X

Case Lining 3.9.7.3 4.12.3 X

Spectacle Identification 3.10.1 N/A X

Protective Case Identification 3.10.2 N/A X

Defects in Viewing Surface 3.11.1 4.13.1 X

(Includes all requirements within this specification. These tests are performed on EDM units.)

Conformance Area / Test Requirement

Paragraph

Verification

Paragraph

Verification Method

In sp ec ti al y si s

T o n st ra ti

Frame Defects 3.11.2 4.13.2 X

Maintenance 3.12.1 4.14.1 X X

Mean Time to Repair 3.12.2 4.14.2 X

Reliability of LEP Spectacle 3.13 4.15 X X

4.3 Conformance inspection.

Conformance inspections shall include the requirements and verification examinations and tests listed in TABLE III.

TABLE III. Conformance – Verification Cross Reference

Conformance Area / Test Requirement

Paragraph

Verification

Paragraph

Verification Method

In sp ec ti al y si s

T es t

D em o n st ra ti

Laser Protection 3.4 4.6 X

Vertical Prismatic Deviation 3.6.1 4.8, X

Horizontal Prismatic Deviation 3.6.2 4.8, 4.8.2 X

Spherical and Cylindrical Power 3.6.3 4.8, 4.8.3 X

Optical Distortion 3.6.4 4.8, 4.8.4 X

Haze 3.6.5 4.8, 4.8.5 X

Photopic Luminous Transmission 3.7.1 4.9.1 X

Scotopic Luminous Transmission 3.7.2 4.9.2 X

P43 Transmission 3.7.3 4.9.3 X

Erythemal Ultraviolet

Transmittance

3.7.4 4.9.4 X

Red Edge Visibility 3.7.5 4.9.5 X

Lens Fit 3.9.5 4.11.6 X

Spectacle Identification 3.10.1 N/A X

Protective Case Identification 3.10.2 N/A X

TABLE III. Conformance – Verification Cross Reference

Conformance Area / Test Requirement

Paragraph

Verification

Paragraph

Verification Method

In sp ec ti al y si s

T es t

D em o n st ra ti

4.4 Inspection lot.

Inspection lot shall consist of the examinations and tests as specified in Error! Reference source not found.. Failure of a lot sample shall result in rejection of the lot. Random samples shall be selected in accordance with ANSI/ASQC Z-1.4.

TABLE IV. Inspection Lot – Verification Cross Reference

Conformance Area / Test Requirement

Paragraph

Verification

Paragraph

Verification Method

In sp ec ti al y si s

T es t

D em o n st ra ti

Laser Protection 3.4 4.6 X

Haze 3.6.5 4.8, 4.8.5 X

Photopic Luminous Transmission 3.7.1 4.9.1 X

Scotopic Luminous Transmission 3.7.2 4.9.2 X

P43 Transmission 3.7.3 4.9.3 X

Erythemal Ultraviolet

Transmittance

3.7.4 4.9.4 X

Red Edge Visibility 3.7.5 4.9.5 X

Spectacle Identification 3.10.1 N/A X

Protective Case Identification 3.10.2 N/A X

4.5 Design verification.

4.5.1 Prescription eyewear compatibility.

If prescription lens solution entails the use of a component attached to the spectacles, then it shall be verified that the solution meets the requirements of 3.3.3. This test shall be accomplished with prescription eyewear of ±4.0 diopters of sphere and -2 diopters of cylinder.

4.5.2 Weight.

Spectacles shall be weighed on a balance or scale with a resolution of 0.001g. Spectacles shall be weighed both with and without Rx solution.

4.6 Laser protection.

The lens shall be tested to demonstrate the wearer is protected throughout the entire safety zone as defined in ANSI Z136.7. Optical density shall be verified at each threat wavelength or wavelength range using laser sources of the appropriate wavelength. Laser source shall have a bandwidth no greater than 1nm. OD shall be verified throughout the entire specified wavelength protection bands where lasers were not used, using a measurement system of appropriate wavelength range and dynamic range for the OD being measured. Optical density and angular testing shall be performed to test the full protection of the safety zone, up to the frame edge when it falls within the safety zone projected angle.

4.6.1 Reflective filtering technologies.

The optical density shall be verified using parameters specified in TABLE I of this specification with an eye relief of 12mm. The laser shall be circularly polarized or ‘P’ polarized with respect to the lens surface angle of incidence. Test points measurements shall be performed in the horizontal and vertical directions in increments equal to the beam diameter along the four axes/meridians pictured in FIGURE 1. Testing shall conform to ANSI Z136.7, Test Methods, Optical Density, and Appendix D – Procedure for Laser Based Testing of OD for Reflective

Filters.

4.6.2 Absorptive filtering technologies.

The optical density shall be verified by conforming to ANSI Z136.7, Test Methods, Optical

Density, and Appendix C – Procedure for Laser Based Testing of OD for Absorptive Filters. For lenses of non-uniform thickness, OD shall be measured at the thinnest point of lens. Laser incidence angle shall be normal.

FIGURE 1. Test Point Meridians and Nomenclature

4.7 Compatibility.

4.7.1 Physical compatibility.

The LEP spectacle, with and without prescription, shall be donned with the gear identified in section B-2, Appendix B, to verify fit and compatibility; such as fit and comfort, physical interference (both static and moving), misalignments that cause improper viewing of helmet-mounted displays, or reduction in the field of view. Fit and comfort will be evaluated in an aircraft environment representative of all aircraft listed in TABLE B-I, Laser Eye Protection

Interface Control Requirements, section B-2, Appendix B. Test subjects and aircrew will wear

LEP, note physical incompatibilities (discomfort and hot spots), deficiencies, and impact on mission performance using the Bedford Workload rating scale. TABLE V details the subjects required for each of the tests detailed in section B-3, Appendix B.

TABLE V. Test Subject Population Breakdown

Males (48 subjects)

IPD IPD IPD

Head Breadth 54-59mm Head Breadth 59.5-62mm Head Breadth 62.5-68mm

138-151

(5.43-5.94 in) 6 subjects

142-152

(5.59-5.98 in) 6 subjects

141-152

(5.55-5.98 in) 8 subjects

151-156

(5.94-6.14 in) 4 subjects

152-156

(5.98-6.14 in) 4 subjects

152-156

(5.98-6.14 in) 6 subjects

TABLE V. Test Subject Population Breakdown

156-175

(6.14-6.89 in) 4 subjects

156-174

(6.14-6.85 in) 4 subjects

156-168

(6.14-6.61 in) 6 subjects

Females (35 subjects)

IPD IPD IPD

Head Breadth 56.5-61mm Head Breadth 61.5-65.5mm Head Breadth 66-71mm

131-143

(5.16-5.63 in) 4 subjects

133-143

(5.24-5.63 in) 4 subjects

135-145

(5.31-5.71 in) 6 subjects

143-148

(5.63-5.83 in) 3 subjects

143-146

(5.63-5.75 in) 4 subjects

145-147

(5.71-5.79 in) 5 subjects

148-170

(5.83-6.70 in) 2 subjects

146-159

(5.75-6.26 in) 3 subjects

147-163

(5.79-6.42 in) 4 subjects

NOTE:

This table was generated from naval aviation population based on a 2002 survey of 747 naval aviation personnel.*

* these dimensions match Joint Strike Fighter population

4.7.1.1 Fitting time.

Time required to fit the LEP shall be verified by demonstration in a lab environment. A

Parachute Rigger or Flight Equipment Technician familiar with applicable fitting procedures shall conduct the demonstration and fitting time shall be recorded.

4.7.2 Visual compatibility.

Visual compatibility tests shall be conducted in an aircraft environment representative of all aircraft listed in Table B-1. Day, night, and transition lighting conditions shall be targeted for this evaluation. Applicable visors and HMDs shall be evaluated in each lighting condition. Test subjects shall consist of qualified aircrew and shall evaluate the visual compatibility of the LEP spectacles through the use of mission performance based measures, such as the Bedford

Workload or Hawthorn-Newman Display Readability Scales, and through human factors questionnaires. Visual compatibility with cockpit and cabin interior lighting and displays, aircraft windscreen and canopy, Heads Up Displays (HUDs), targeting systems, maps and other printed materials, exterior aircraft lights, airfield lights, terrain colors, visibility of geographic formations, and performance of normal aircrew duties shall be assessed. Tests shall be conducted with a minimum of three prescription users. Tests shall be conducted with a minimum of three non-prescription users.

4.7.2.1 Visual acuity.

Visual Acuity shall be assessed in an aircraft environment. Distance Visual Acuity shall be assessed using eye charts placed an appropriate distance outside the aircraft. Near Visual Acuity shall be assessed using eye charts at a distance of 406.4 mm (16 inches) from the test subject.

4.7.2.2 Eye strain.

Subjects shall fill out a survey provided by the Government to develop a baseline score prior to testing. Subjects shall then wear LEP spectacles in a simulated mission representative environment for three consecutive hours. Subjects shall then fill out the survey again and a delta from the baseline shall be computed. After 24 hours subjects shall fill out a survey and a delta from the baseline shall be computed.

4.7.2.3 Farnsworth Munsell Hue-100.

The Farnsworth Munsell Hue-100 test shall be performed in accordance with the Farnsworth document referenced in Section 2. Test shall be conducted under a D65 Illuminant using binocular vision. A baseline score shall be generated by having subjects initially perform the test without spectacles donned. The test shall be repeated with spectacles donned and scores shall be generated. Degradation of performance shall be calculated by subtracting the donned score from the baseline.

4.8 Optical quality.

The optical quality tests below shall be measured in the "as worn" position, at the area of the lens defined by the design eye point. Prismatic deviation measurements may use a telescope, lens meter, or optical beam deviation along the selected line of sight.

FIGURE 2. Lens Test Locations

4.8.1 Vertical prismatic deviation.

BASE UP prism shall be designated positive (+) and BASE DOWN prism shall be designated negative (-). The vertical prismatic deviation imbalance shall be calculated by determining the algebraic difference between the prism at the right and left design eye points. The vertical prismatic deviation shall meet the requirements of 3.6.1. Test shall be conducted using the test location identified in Figure 2. Point 1 is located directly in front pupil location. Points 2, 3, 4, and 5 are located 15 degrees off axis. For comparison: points 2L shall be compared with 3R, and

2R shall be compared with 3L as these are the points that a user would be looking through at the same time when looking left or right.

4.8.2 Horizontal prismatic deviation.

BASE OUT prismatic deviation shall be designated positive (+) and BASE IN prismatic deviation shall be designated negative (-). The horizontal prismatic deviation imbalance shall be calculated by determining the algebraic sum between the amount of prism at the right and left design eye point. Test shall be conducted using the test location identified in Figure 2. Point 1 is located directly in front pupil location. Points 2, 3, 4, and 5 are located 15 degrees off axis. For comparison: points 2L shall be compared with 3R, and 2R shall be compared with 3L as these are the points that a user would be looking through at the same time when looking left or right.

4.8.3 Spherical and cylindrical power.

The lens shall be tested for spherical and cylindrical power. Spherical and cylindrical power shall be measured in accordance with ANSI Z87.1 using a telescope, vertometer or lens meter

(minimum resolution of .01 D). Spherical and cylindrical power shall meet the requirements of

3.6.3.

4.8.4 Optical distortion.

The lens shall be tested for optical distortion in accordance with MIL-DTL-43511.

4.8.5 Haze.

Haze shall be determined in accordance with Procedure A of ASTM-D1003.

4.9 Luminous transmittance.

The spectral transmittance shall be measured using a spectrophotometer from 270 to 1200 nm at increments of 1 nm or less to ensure capturing of both the visible and infrared portions of the spectrum. The computed transmissions [PLT, SLT, and P43] of the right vs. left lens, in each pair of LEP spectacles, shall differ by no more than 10%, as shown by example in Appendix A, TABLE A-I. TABLE A-II, Appendix A lists only the visible portion of the spectrum that is required for calculating the photopic, scotopic, and P43 transmittances.

4.9.1 Photopic luminous transmittance.

Photopic luminous transmittance shall be calculated from the spectral transmission measurement of 3.7, according to Equation A-1 and Figure A-1, Appendix A.

4.9.2 Scotopic luminous transmittance.

Scotopic luminous transmittance shall be calculated from the spectral transmission measurement of 3.7, according to Equation A-1 and Figure A-1, Appendix A.

4.9.3 P43 transmittance.

P43 Transmittance shall be calculated from the spectral transmission measurement of 3.7, according to Equation A-1 and Figure A-1, Appendix A.

4.9.4 Erythemal ultraviolet transmittance.

The erythemal ultraviolet transmittance of the lens shall be computed by averaging the transmittance at 290, 300, 310 and 320 nm.

4.9.5 Red edge visibility.

From the transmission spectral measurement of 3.7.5, red edge, as specified, shall be reported in nanometers (nm).

4.10 Environmental tests.

Before performing the environmental tests, LEP spectacles shall be measured and meet the requirements of optical density, optical distortion, haze, luminous transmittance, and workmanship. LEP spectacles shall be placed in the environmental chamber to allow adequate circulation around the item, with the exception of High and Low temperature testing which is conducted with LEP in case. Interruptions during which the prescribed test tolerances are not exceeded shall be considered as part of the total test duration. Unless otherwise specified, digital photographic documentation is required for test reporting to indicate proximity of sensors, and to document the appearance of LEP spectacles before and after environmental conditioning tests.

Digital photographs shall be required to document any visible damage to the lens or frame.

Videotape records of resolution equivalent to photographs may be substituted wherever photographs are required in the test procedures.

4.10.1 Solar radiation.

The LEP shall be placed in a solar simulator and tested to the methods defined in MIL-STD-

810G, Solar Radiation Exposure, Procedure II. The total incident flux shall be monitored and recorded throughout the exposure. The exposure test cycle shall be repeated until the LEP spectacles fail or the equivalent of 200 hours is reached. The LEP spectacles shall be placed in the test chamber ensuring that it is positioned so that the entire front surface can be photographed from the viewing port without disturbing the sample. A white light source shall be placed behind the sample so the illumination is uniform throughout the sample. Photographs shall be taken at stabilization temperature and at 5 hour intervals during the light phase of the 24 hour cycle.

4.10.2 Laser saturation.

Lenses that utilize an absorptive material for reducing transmission of threat wavelengths shall be tested for laser induced changes at those particular threat wavelengths as specified in ANSI

Z136.7, Test Protocols, Saturable Absorption, and Appendix B - Procedure for Laser Based

Testing of OD for Absorptive Filters. Lenses shall be exposed to Q-switched energy levels specified in TABLE VI based on OD levels specified inAppendix C. The results shall be stated in terms of wavelength and energy density at which bleaching and/or damage occurs.

TABLE VI. Exposure Levels for Laser Saturation Testing

DESIGN

OPTICAL

DENSITY

>180-1400 nm

Q-switch pulse width = 10 -9

- 10 -5

Minimum Exposure (J/cm

4 5 × 10 -3

5 5 × 10 -2

6 5 × 10 -1

7 5

4.10.3 High temperature.

High temperature test shall be conducted IAW MIL-STD-810G, Method 501.5, using Procedure

I - Storage, and Table 501.5-III, for seven cycles.

4.10.4 Low temperature.

Low temperature test shall be conducted IAW MIL-STD-810G, Method 502.5, using Procedure

I–Storage, for 3 cycles. Soak time shall be 10 hours after low temperature stabilization.

4.10.5 Temperature shock.

Temperature shock test shall be conducted IAW MIL-STD-810G, Method 503.5, Procedure I-D, and the following exposure conditions.

Step 1. Place the LEP in the test chamber.

Step 2. Raise the internal chamber temperature to 71°C ± 1° (160°F) at a rate no greater than

3°C/min (5°F/min).

Step 3. Maintain at high temperature for a period of four hours after temperature stabilization.

Step 4. Transfer the LEP within 1 minute, to a chamber with controlled ambient conditions, IAW MIL-STD-810G, until LEP reaches temperature stabilization.

Step 5. Remove LEP from chamber. Inspect, photograph, and record the results.

Step 6. Repeat steps 1 thru 5, two more times for a total of 3 cycles.

Step 7. Place the LEP in the test chamber.

Step 8. Lower the internal chamber temperature to -54°C ±2° (-65°F) at a rate no greater than

3°C/min (5°F/min).

Step 9. Maintain the LEP at low temperature for a period of 4 hours after temperature stabilization.

Step 10. Transfer LEP within 1 minute, to standard ambient conditions, IAW MIL-STD-810G.

Step 11. Inspect, photograph, and record results immediately after LEP defrosts, and again at 1 and 4 hours periods.

Step 12. Repeat steps 7 thru 11 two more times for a total of 3 cycles. Ensure that lenses are clean before placing back into chamber.

4.10.6 Humidity.

Humidity test shall be conducted IAW MIL-STD-810G, Method 507.5, using Procedure II–

Aggravated Cycle (Figure 507.5-7), for 10 cycles. Duration consists of one 24-hr conditioning period, followed by ten 24-hr cycles, for a total of 11 days or 264 hours. At test completion, the device shall be removed from the chamber. Ensure lenses are clean, photograph and inspect in detail to document the condition of lenses and coatings.

4.10.7 Salt fog.

The LEP shall be tested for salt fog effects as outlined in this section. The salt used for this test shall be sodium chloride containing (on a dry basis) not more than 0.1 percent sodium iodide and not more than 0.5 percent total impurities. A 5 ± 1 percent solution shall be prepared by dissolving 5 parts by weight of salt in 95 parts by weight of water. The solution shall be adjusted to, and maintained at, a specific gravity by using the measured temperature and density of the salt solution. Sodium tetra borate (borax) may be added to the salt solution as a pH stabilization agent in a ratio not to exceed 0.7g sodium tetra borate to 75 liters of salt solution. The pH of the salt solution as collected as fallout in the exposure chamber shall be maintained between 6.5 and

7.2 with the solution temperature at +35°C (+95F). Only diluted chemically pure hydrochloric acid or chemically pure sodium hydroxide shall be used to adjust the pH. The pH shall be assessed electrometrically or colorimetrically.

Step 1 Adjust the test chamber temperature to 35°C ±1° (95F ± 2). Photograph the LEP.

Step 2 After introduction of salt fog, the LEP spectacles shall remain in the chamber for 48 hours.

Step 3 Remove the LEP from the chamber. Wash and photograph the LEP.

Step 4 The LEP shall be stored at ambient temperature for 48 hours. Photograph the LEP at the end of this period.

4.10.8 Chemical.

All external lens coatings of LEP shall be exposed to the chemicals listed in 3.8.8 for a 24 hour period at ambient room temperature conditions. At least 3 drops of the chemical shall be puddled on the lens surface. A drop shall be at least 1 ml in volume.

4.11 Mechanical.

4.11.1 Taber abrasion resistance.

The surface abrasion procedure shall be performed as specified in ASTM-D1044, using an abrasion of 500 cycles with a 500 gram load on 4 inch by 4 inch flat samples which are coated by the same material and process as the lens. The sample plate shall be provided with test point locations.

4.11.2 Bayer abrasion resistance.

An uncut lens blank which is coated by the same material and process as the LEP lens shall be tested using the oscillating sand method for 600 cycles as defined in ASTM-F735. Replacement of Alundum with Kryptonite B is authorized. A CR-39 reference lens or equivalent of same size, shape and curvature will be tested in parallel with the coated specimen. The resulting ratio will be the change in haze, tested using ASTM-D1003, of the reference specimen divided by the change in haze of the coated specimen.

𝐵𝑎𝑦𝑒𝑟 𝑅𝑎𝑡𝑖𝑜 =

(𝑃𝑜𝑠𝑡 𝑡𝑒𝑠𝑡 𝐻𝑎𝑧𝑒 𝐶𝑅−39)−(𝑃𝑟𝑒 𝑡𝑒𝑠𝑡 𝐻𝑎𝑧𝑒 𝐶𝑅−39)

(𝑃𝑜𝑠𝑡 𝑡𝑒𝑠𝑡 𝐻𝑎𝑧𝑒 𝑇𝑒𝑠𝑡 𝑆𝑎𝑚𝑝𝑙𝑒)−(𝑃𝑟𝑒 𝑡𝑒𝑠𝑡 𝐻𝑎𝑧𝑒 𝑇𝑒𝑠𝑡 𝑆𝑎𝑚𝑝𝑙𝑒)

4.11.3 Lens coating adhesion resistance.

The lens shall be clean and dry, stabilized at room temperature, then subjected to the adhesion test as described. Tape used shall be IAW Commercial Item Description, A-A-113D, Type 1, Class B, 1/2 inch wide, except that the tape may be clear. Press a strip of pressure sensitive tape firmly across the entire span of each coated lens surface, removing all air entrapment. The time between application and removal of tape shall be less than one minute. Remove the tape by a rapid pull force applied approximately perpendicular (right angle) to the test area. This test shall be repeated immediately upon completion of the humidity test and after drying the lens thoroughly.

4.11.4 Impact resistance.

Using at least three (3) complete, LEP spectacles, test impact as specified in ANSI/ISEA Z87.1-

2010, Drop Ball Test.

4.11.5 Prescription lens carrier impact resistance.

Prescription lens carrier, as installed, shall be subjected to the high mass impact test, IAW

ANSI/ISEA Z87.1-2010, with the following modifications to sample quantities. For each spectacle size, a total of 3 frames shall be tested, with representative Rx lenses installed, one each of the following lens prescriptions:

Rx of +4.0 D sphere/-2.0 D cylinder

Rx of -4.0 D sphere/-2.0 D cylinder

Rx of 0.0 D sphere/0.0 D cylinder

Both left and right lenses shall be tested for each Rx configuration, resulting in a total of 6 tests for each frame size.

4.11.6 Lens fit.

The contact area between the frame and lens shall be inspected with a strong, neutral, non-glaring light from behind. Any visible light between the frame and lens indicates a space exists between the frame and the lens and shall be cause for rejection.

4.11.7 Frame ductility.

The temple arms of the LEP frame shall be bent 45 (once) over a 6 mm (0.25 inch) mandrel.

4.11.8 Frame adhesion of plating.

Sample used to verify this requirement shall have previously undergone the High and Low

Temperature tests, Temperature Shock, Humidity, and Salt Fog tests of 4.10. Adhesion of test articles shall be performed at room temperature by means of the following bend test. Plated temple arms shall be bent repeatedly through an angle of 180 on a diameter equal to the thickness of the temple arm until fracture of the base material occurs. No detachment of the coating shall be possible by probing with a sharp instrument. Cracks in the base metal or plating shall not be considered failure unless accompanied by flaking, peeling, or blistering.

4.12 Protective carrying case.

4.12.1 Transit drop.

A Transit Drop test shall be conducted IAW MIL-STD-810G, Method 516.6 Procedure IV. The

LEP spectacles in the case shall fall on a piece of two-inch thick piece of plywood backed by concrete from a height of 5 meters.

4.12.2 Crush resistance of carrying case.

The case, with the lens type protection inside, in the closed position, shall be on a flat surface. A force of 13.3 kg (29 pounds) shall then be applied over a circular area of 160 mm (0.25 square inches) on the face of the closed case over the center of each lens.

4.12.3 Case lining.

The requirement shall be verified through a visual examination and inspection of the case.

4.13 Workmanship.

4.13.1 Defects in viewing surface.

Lenses shall be examined using normal day light conditions, both in reflection and transmission.

The LEP spectacles shall be examined using a template to define the central viewing area and meet requirements as specified. When a defect is detected, a microscope of sufficient power shall be used to measure flaw.

4.13.2 Frame defects.

The frame shall be visually inspected for mechanical damage or warping. The frame shall be physically examined for sharp edges or burrs. The examination shall consist of donning a pair of clean cotton gloves, and running the palm along the entire edge of the frame.

4.14 Maintainability.

4.14.1 Maintenance.

Maintenance shall be verified through demonstration during the ground and flight test phase of the program.

4.14.2 Mean Time to Repair (MTTR).

The LEP spectacles maintainability shall be verified through…