Attachment_0004_-_RA1_Manufacturing_Specification_2-8-2016.pdf

08 February 2016 supersedes 06 March 2015

Manufacturing Specification For:

RA-1 Parachute System:

P/N 11-1-9100

1. SCOPE

1.1. Scope. This specification covers detail instructions relative to the dimensions, tolerances, repair procedures and other specific manufacturing instructions to be used in the assembly of the RA-1 parachute system.

2. APPLICABLE DOCUMENTS

2.1. General. The documents listed in this section are cited in sections 3 and 4 of this specification. These lists do not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of these lists, document users are cautioned that they must meet all specified requirements documents cited in sections 3 and 4 of this specification, whether or not they are listed.

2.2. Government Documents.

2.2.1. Specifications and Standards. The following specifications and standards form a part of this document to the extent herein. Unless otherwise specified, the issues of these documents are those listed in the issue of the Department of Defense Index of Specifications and Standards (DoDISS) and supplement thereto, cited in the solicitation (see 5.2).

SPECIFICATIONS

DEPARTMENT OF DEFENSE

MIL-DTL-6645 - Parachutes, Personnel, General Specification for

STANDARDS

DEPARTMENT OF DEFENSE

MIL-STD-849 - Inspection Requirements, Definitions and Classification of Defects in Parachutes

2.2.2. This document supersedes MIL-DTL-7567 for manufacture of the RA-1 parachute system.

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2.3. Non-Government Publications. The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of the documents that are DoD adopted are those listed in the issue of the DoDISS cited in the solicitation. Unless otherwise specified, the issues of documents not listed in the DoDISS are the issues of the documents cited in the solicitation.

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM D6193 – Standard Practice for Stitches and Seams

(Application for copies should be addressed to the American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.)

2.4. Order of Precedence. In the event of a conflict between the text of this document and the references cited herein (except for related associated specifications or specification sheets), the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

3. REQUIREMENTS

3.1. General Requirements of the Parachute System.

3.1.1. Definitions of Nomenclatures. See MIL-STD-849 and Specification Conversion Table for any applicable deviations to MIL-STD-849.

3.1.2. Materials. Materials shall conform to the requirements on the applicable drawings and to subsidiary specifications and standards applicable thereto.

3.1.3. Material Defects. The acceptability of materials used in the manufacture of the RA-1 system shall be governed by the pertinent specification unless waived by the procuring activity. During the spreading, cutting and manufacturing process, components having material defects or damages that are classified as defects in the applicable specifications shall be removed from production and replaced with non-defective components. Materials damaged during rework/repairs shall be cause for total rejection of the damaged section/component.

3.1.4. Construction. The construction shall conform in all respects to the applicable drawings and as specified herein.

3.1.5. General Quality Guidelines.

3.1.5.1. Cut ends of webbing, tape, and hook and loop fastener tape must be cut neatly and straight.

Unless the cut is intentionally angled, the cut must be square to the material. Heat sealed ends shall be free of sharp edges and have a cleanly burned appearance.

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3.1.5.2. Unless an offset is specified, the edges of sewn material layers must be neatly aligned.

3.1.5.3. Turnbacks must be neatly formed with the turned back end of the material neatly aligned with itself.

3.1.5.4. Stitching is to be straight, tensions equal, and pucker minimized. Seams shall be neatly sewn, with consistent seam margins, and with minimal deviation from the contours – curved stitching shall reasonably follow the edge.

3.1.6 Use of Hot Glue. When hot glue is used as a temporary bonding aid in preparation for sewing or assembly, prior Government approval is required. When applying hot glue, a minimal quantity should be used to prevent unnecessary stiffening of the assembly. Hot glue shall be neatly applied with minimal squeeze-out from plies and joints. Excess glue visible in the folds or layers of the material is not permitted.

3.1.7. Dimensions.

3.1.7.1. Cloth Dimensions after Cutting. The dimensions of fabric sections after cutting are not required to duplicate the measurements in the applicable TDP because the latter dimensions are intended for the pattern only. Variation in the finished size of the cut shape due to humidity or relaxation of tension after cutting and variation of measurement from the top to the bottom of the lay after cutting shall be recognized.

3.1.7.2. Cut Dimensions on Parts Lists (PL). On parts lists, cut dimensions in parentheses are for reference only. Finished dimensions for these items are specified in the detail drawings. Cut dimensions not in parentheses are subject to the tolerance block of the applicable detail drawing and not subject to a finished dimensional tolerance.

3.1.7.3. Symmetry of Like Features. Manufacturing tolerances shall be as specified on the drawings.

Unless otherwise specified on the detail drawings variation in symmetry of like features shall be kept within one-half of the total permitted tolerance. For example if a tolerance is stated as ±1/4", the total permitted variation is 1/2 inch. However, the maximum variation between the like features may be 1/4 inch.

Centered Dimensions. In many instances one or more items of a defined length or width are centered on one another rather than being dimensioned from an external point. If these layers of materials were simply dimensioned either from one end or from one edge then the tolerances on the individual lengths or widths combined with the tolerance on the positioning dimension could dramatically affect the centering alignment. To address this RA-1 has adopted a convention of dimensioning to one end or edge with the notation “CENTERED ±X”. For example if this were CENTERED ±1/16 the intent is that the actual center of the item must fall within 1/16 inch of the nominal center. Centering is checked by measuring from each end or edge and determining the difference. With the example tolerance the two dimensions would differ by a

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maximum of 1/8 inch. This method allows for accurate centering without a series of excessively tight controlling tolerances on the component items, or, in the case of two different width webbings/tapes allows for accurate centering by negating the effect of allowable material width variations.

3.1.7.4. Measuring. Unless a specific tension requirement is stated on the drawing, dimensions shall be measured under hand tension. Proper hand tension is that which is sufficient to remove slack and/or pucker from the item without stretching. Nominal hand tension is generally considered to be approximately 3 – 5 pounds.

3.1.8. Cutting and Searing. Methods of pattern cutting and hot cut/searing or scissor cutting of raw edges of tape, webbing, and cord shall be as specified on the applicable drawings.

3.1.9. Cleaning. Spot-cleaning of textiles can be performed using exclusively the following:

EverBlum Spray-A-Spot cleaning fluid

Water

A soap and water solution using a mild, neutral soap, such as Ivory

A light dusting of baby powder can be used to extract oil. Baby powder must be gently brushed or blown off.

Care shall be taken with all cleaning methods to avoid discoloration or spotting of materials. All cleaning methods should be gentle; abrasive or aggressive agitation of the textiles is to be avoided.

3.1.10. Edge Binding. Binding shall be neatly applied with the bound fabric being caught by both rows of stitching. Corners shall be neatly turned with the tucked binding fold secured by stitching and no looping of the thread. Radiused corners shall be smoothly turned.

Binding shall be applied with start/stop locations as defined in the detail drawings. Unless otherwise specified binding terminations shall be heat sealed smoothly and flush with the edge on which it terminates.

3.1.11. Stitching. The tension of bobbin and needle thread shall be approximately equal such that both threads lie smoothly on the two surfaces of the material without looping, and the interlock falls between the top and bottom layers of fabric. Ideally, the knot will be centered and not visible from either side. The tension shall not be so tight as to cause excessive puckering or shrinkage of the fabric, or so loose as to cause loose or looped stitching on either the top or bottom surfaces of the item. Multiple needle machines shall be adjusted to provide approximately balanced tension from each needle.

Backstitching shall be as specified on the applicable drawings. See 3.1.11.2 for descriptions of backstitch requirements.

As specified on the detail drawings adjacent rows of 301 stitching shall be superimposed unless spacing is dimensioned. As a guideline, the space between superimposed stitching should not

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deviate by more than 1/16 inch.

Stitching repairs to both rows of double needle seams shall be done with a double needle stitch of the same gage as that being repaired. Repairs to one row of double need stitching may be done with a single row of stitching provided even spacing between rows is maintained. All stitching repairs shall be made with matching color thread of the same type and stitch length, with the repair stitching neatly superimposed over the existing stitching, and with the overlaps formed as specified in section 3.1.11.3. All fragmented pieces of sewing thread must be removed from the seam.

Many materials exhibit non-damage evidence of stitching repair. Evidence of stitching removal in the form of disturbed yarns, and halos in resins, coatings, and finishes shall not be considered defects. Reasonable effort shall be made to settle disturbed yarns back into place prior to re-sewing.

3.1.11.1. Bartacks. Bartacks are defined by stitch count (total number of stitches forming the bartack) and the finished width and length of the pattern. Actual stitch count may be ±2 stitches.

Bartacks shall be as specified in the detail drawing. Bartack width can measure differently on the top and bottom surfaces of the part. The width shall be considered compliant if one of the two sides conforms to specifications.

Bartack quality guidelines:

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3.1.11.2. Backstitching. Backstitch requirements are specified on the detail drawings. Backstitching is not required if not specified on the drawing. The following terminology is used to define three different types of backstitch: Single Leg Backstitch, Backstitch, and Double Backstitch (see Figures 1, 2, 3 for formation requirements). The figures apply to backstitches sewn with both type 301 straight stitch and 308 zigzag.

Figure 1 Single Leg Backstitch

Section View

Figure 2 Backstitch

Section View

Figure 3 Double Backstitch

Section View

3.1.11.3. Stitching Overlaps (splices). Unless defined on the detail drawing, the location of the stitching start/stop point is optional. Stitching overlap requirements are as follows:

Size E, Type 301 3 inches ±1 inch

Size E, Type 308 1/2 inch ± 1/4 inch

Size FF, Type 301 2 inches ± 1/2 inch

Size 5, Type 301 1 1/2 inch ±1/2 inch

3.1.11.4. Thread Ends. Thread ends shall be trimmed to 1/2 inch or less.

3.1.11.5 Grommets. Grommets shall be set securely with no sharpness along the inside of the barrel.

Soft ridges in the barrel are acceptable. A securely set grommet shall be defined as one in which the teeth are not visible when the fabric is peeled away from the spur. If set into uneven thickness, visible teeth are acceptable in the thinner locations provided the grommet is securely set in the thick locations.

Flaked plating is not acceptable. When set into thin materials, the teeth of spur washers may be evident pressing against the grommet. This is acceptable so long as setting criteria above is maintained. Cut ends of material shall not protrude from under the grommet or from under the rolled barrel.

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3.1.12. Frequency of Repairs. Frequency of repairs to the canopy, pilot chute, container, deployment bag and pocket are specified below. See section 3.4 for repairs to other components of the parachute system, along with exceptions and limitations.

Length of Seams (inches) Number of Repairs

Up to 2 0

Over 2 up to 72 1

Over 72 up to 240 2

Over 241 up to 360 3

3.2. Canopy and Pilot Chute. The canopy assembly consists of the canopy, suspension lines, slider, and connector links.

3.2.7. Applicability. Section 3.2 applies to the following part numbers:

11-1-9102-1 CANOPY ASSY, MAIN, RA-1

11-1-9103-1 CANOPY ASSY, RESERVE, RA-1

11-1-9109-1 PILOT CHUTE, MAIN, RA-1

11-1-9112-1 DROGUE CANOPY ASSY, RA-1

11-1-9130-1 SLIDER, MAIN, RA-1

11-1-9131-1 SLIDER, RESERVE, RA-1

11-1-9132-1 SUSPENSION LINES, MAIN, RA-1

11-1-9133-1 SUSPENSION LINES, RESERVE, RA-1

11-1-9134-1 STEEERING LINES, MAIN AND RESERVE, RA-1

11-1-9137-1 PILOT CHUTE, RESERVE, RA-1

3.2.8. MIL-STD-849 Reference. Refer to Table XII for Items 11-1-9109-1, 11-1-9112-1 and 11-1-9137-1.

Refer to Table XVIII for all other items.

3.2.9. Darns. No darns are acceptable on main and reserve parachutes, main and reserve sliders, pilot chutes, or drogues.

3.2.10. Hot Tacks. No hot tacks (needle tacks) are authorized. Hot tacks are defined as any technique

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used to temporarily bond materials in preparation for sewing or assembly by melting or heat sealing the materials together.

3.2.11. Pleats. Pleats are defined as folds in the cloth caught by the stitching that is approximately perpendicular to the seam. Pleats are permitted as follows:

a. Canopy top and bottom rib seams- Pleats up to 1/16 inch in wide, and 1 pleat per seam are acceptable

b. Canopy tail seam- Pleats up to 1/16 inch in width, and up to 3 pleats per tail seam are acceptable. Pleats may be no closer than 50” apart. Note: folds in the rolled cloth that do not extend into the top or bottom panels are not counted as pleats.

c. Pilot chutes- Pleats 3/16 inch or less occurring in the pilot chute canopy at the cap are acceptable.

3.2.12. Stitching. Stitching requirements for canopies, pilot chutes, and drogues shall be as specified in section 3.1.11.

3.2.13. Stitching Defects and Repairs. A stitching repair shall be considered to be all the overlapping and the stitching required to correct stitching that is not in accordance with applicable drawings.

Repairs to stitching shall not be made if the original stitching has damaged the cloth, webbing or tape, or cord.

3.2.14. Improper Tension. Stitching with improper tension that is too tight or too loose shall be removed and replaced, as specified in 3.1.11 with stitching of proper tension. (Tension shall be determined by a firm pull with the hands along the line of stitching. If the tension is too tight, the stitching will break or appear tight to the point of breaking. If the tension is too loose, the stitching will appear as a series of loops.) See 3.1.13 for frequency of repairs.

3.2.15. Run-offs. Run-offs onto a single layer of cloth or beyond the seams or hem margins shall be removed and replaced as specified in 3.1.11. See 3.1.13 for frequency of repairs.

3.2.16. Kinks. Kinks (also called “knotty thread”) may occasionally be encountered. Stitching containing kinks that are closer to each other than 2 inches shall be reinforced as specified in 3.2.18 See

3.1.11 for frequency of repairs.

3.2.17. Splices. The stitching splices shall be either superimposed stitching or adjacent stitching that is placed a maximum of 1/16 inch, but within the minus tolerance specified for the seam margins, from the stitching which is being spliced. Overlaps shall be formed as specified in 3.1.11.3. See

3.1.13 for frequency of repairs.

3.2.18. Reinforcement Stitching. Reinforcement stitching shall lie adjacent to, or superimpose, the stitching being reinforced but shall not exceed the minus tolerance specified for the seam margins. Reinforcement stitching shall reasonably match the length and the tension of the stitches being reinforced, and the stitching shall overlap each end of the defective stitching 1 inch. See 3.1.13 for frequency of repairs.

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3.2.19. Replacement of Stitching. Replacement stitching shall overlap the existing stitching as specified in 3.1.11.3. See 3.1.13 for frequency of repairs.

3.2.20. Seams. Repairs to defective stitching. Defective stitching on seams due to incorrect number of stitches per inch may be repaired in accordance with the following conditions and limitations.

a. Fewer than the allowable stitches per inch and any length: Repair in accordance with 3.1.11.

See 3.1.13 for frequency of repairs.

b. More than the allowable stitches per inch and not over 12 S.P.I. for a distance of less than 2 inches: No repairs are allowed. The defective stitching is allowed if no more than 1 defect per slider and no more than 4 defects per canopy exist and the defective stitching has not damaged the canopy (see 3.2.13).

c. More than the allowable stitches per inch and not over 12 S.P.I. for a distance of more than 2 inches: No repairs are allowed and the defective stitching is not allowed.

d. Exceeding 12 stitches per inch, any length: No repairs are allowed and the defective stitching is not allowed.

e. For any condition, the defective stitching is not allowed if there is visual evidence of canopy damage caused by excessive stitches per inch (see 3.2.13).

f. Seams containing broken or skipped stitches shall be reinforced as specified in 3.2.18. The length of the reinforced stitching shall not exceed 12 inches. Original stitching shall be removed after 12 inches and re-stitched as specified in 3.1.11. See 3.1.13 for frequency of repairs.

3.2.21. Stitch Patterns and Bartacking. No repairs are allowed to defective stitch patterns and bartacking. Provided there is no needle damage, the defective area may be re-sewn.

3.3 Container, Deployment Bags, and Pockets.

3.3.1 Applicability. Section 3.3 applies to the following part numbers:

11-1-9101-1 HARNESS/CONTAINER ASSY, RA-1

(NOTE: THIS SECTION APPLIES TO ALL SIZE E AND SIZE FF STITCHING ON THE

HARNESS/CONTAINER)

11-1-9105-1 D-BAG, SL, INNER, RA-1

11-1-9106-1 D-BAG, SL, OUTER, RA-1

11-1-9107-1 D-BAG, FREE FALL, MAIN, RA-1

11-1-9116-1 RIPCORD, MAIN RELEASE, RA-1

11-1-9121-1 SEAT, RA-1

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11-1-9136-1 D-BAG AND BRIDLE ASSY, RESERVE, RA-1

11-1-9143-1 POCKET, RADIO, RA-1

11-1-9144-1 POCKET, O2, T53, RA-1

3.3.2 MIL-STD-849 Reference. Refer to Table XIX for all items listed.

3.3.3 Stitching. The stitching requirements for harness/containers, deployment bags and pockets shall be as specified in section 3.1.11.

3.3.4 Darns. Holes, cuts and tears are not repairable by darning or patching.

3.3.5 Pleats. Pleats up to 1/16 inch in width, and up to 3 pleats per harness/container are acceptable in the foam liner fabric only. No pleats are allowable in any other location on the harness/container or in any other product.

3.4 Harness, Risers, and Main Static Line.

3.4.1 Applicability. Section 3.4 applies to the following part numbers:

11-1-9101-1 HARNESS/CONTAINER ASSY, RA-1

(NOTE: THIS SECTION APPLIES TO ALL SIZE 5 STITCHING ON THE

HARNESS/CONTAINER)

11-1-9104-1 RISERS, MAIN, RA-1

11-1-9119-1 STATIC LINE, MAIN, RA-1

3.4.2 MIL-STD-849 Reference. Refer to Table XIV for items 11-1-9101-1 and 11-1-9104-1. Refer to Table VII for item 11-1-9119-1.

3.4.3 Stitching. The stitching requirements for harness, risers, and main static lines shall be as specified in section 3.1.11.

3.4.4 Stitch Repairs. The complete removal and replacement of 3 or 4 point stitch patterns shall not be conducted without oversight.

3.4.4.1 Broken Stitches. Broken stitches may be repaired by overlapping the existing stitching on either side of the broken stitching. Overlaps shall be formed as specified in 3.1.11.3. Four repairs are allowed to the harness assembly inclusive of the reserve risers (no more than 1 repair per stitch formation). One repair is allowed to each main riser and main static line.

3.4.4.2 Skipped Stitches. One skipped stitch per stitch pattern will be acceptable on the back strap or the leg strap of the harness with a total of 3 skipped stitches allowed per harness exclusive of the reserve risers. Consecutive skipped stitches are not acceptable. No skipped stitches are allowed on the main risers, reserve risers of the harness, or main static line. Skipped stitches on main and reserve risers may be repaired by reinforcing the existing stitching and overlapping the defective portion 1/2”.

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3.4.4.3 Loops. Loops in the harness’s stitching (excluding the back strap and leg straps) over varying thickness of webbing are acceptable, providing that no loop is in excess of 3/32 inch high or 1 stitch in length, and the loops must be a minimum of 2 inches apart. Three such defects are allowed per harness. Loops are not allowed on other areas of the parachute assembly.

3.4.4.4 Kinks. Kinks are not repairable. Stitching containing kinks are acceptable provided the kinks are no closer than 1 inch apart, the kink is embedded or laying flat on the webbing, and the kinks do not exceed the following limitations: 5 per harness, 2 per riser, and 2 per main static line.

3.5 Bridle Lines, Straps, and Miscellaneous Components.

3.5.1 Applicability. Section 3.5 applies to the following part numbers:

11-1-9108-1 BRIDLE, MAIN, RA-1

11-1-9110-1 CROSS CONNECTOR, RA-1

11-1-9111-1 CONTROL LINE, DROGUE/SLIDER, RA-1

11-1-9115-1 STATIC LINE, RESERVE, RA-1

11-1-9117-1 CONNECTOR LINE, DROGUE/SLIDER, RA-1

11-1-9118-1 TOGGLES, STEERING

11-1-9120-1 LOOP, CLOSING, MAIN, 1.25”

11-1-9122-1 BUTT STRAP, RA-1

11-1-9135-1 SLIDER BUMPER

11-1-9138-1 LOOP, SAFETY STOW, 7 1/2”

11-1-9138-2 LOOP, SAFETY STOW, 7”

11-1-9140-1 RETRACTING LINE, MAIN BRIDLE, RA-1

11-1-9141-1 STRAP, TRIM

11-1-9142-1 LOOP, DEPLOYMENT BAG ATTACHMENT

3.5.2 MIL-STD-849 Reference. Refer to Table XIV for all items listed.

3.5.3 Stitching. The stitching requirements for bridle lines, straps, and miscellaneous components shall be as specified in section 3.1.6.10.

3.6 Workmanship. The parachute assemblies and components shall conform to the quality of product established by this specification and documents referenced herein.

4. VERIFICATION

4.1. Classification of Inspections. The inspection requirements specified herein are classified as followed:

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a. First article inspection (see 4.2).

b. Qualification inspection (see 4.2).

c. Conformance inspection (see 4.2).

4.2. First Article, Qualification and Conformance Inspections. Inspections shall be performed as specified in section 4 of MIL-DTL-6645.

5. NOTES

5.1. Intended Use. The manufacturing instructions covered by this specification are intended to provide additional detailed manufacturing requirements not specified in the TDP.

5.2. Acquisition Requirements. Acquisition documents should specify the following:

a. Title and date of this specification.

b. Issue of DoDISS to be cited in the solicitation and if required, the specification of individual documents referenced (see 2.2.1).

5.3. Manufacturing Specifications. Not all personnel systems use MIL-DTL-7567 as a supplemental manufacturing specification. This RA-1 specific document replaces MIL-DTL-7567 and is not a standardization document.