1、MIL-H-43174C 9 November 1983 SUPERSEDING MIL-H-43174B 12 December 1975 MILITARY SPECIFICATION *HELMET, PARACHUTISTS: FREE FALL This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 helmet . Scope. This document covers the requirements for t
2、he free fall parachutists 1.2 Classification. The helmet shall be two types in the following sizes: Type I - Without communication equipment Type II - With communication equipment Sizes : Small Medium Large 2. APPLICABLE DOCrnNTS * 2.1 Government documents. Unless otherwise specified, the following
3、documents, of the issue in effect on date of invitation for bids or request for proposal, form a part of this document to the extent specified herein: SPEC IF ICATIOM FEDERAL PPP-B-636 - Boxes, Shipping, Fiberboard Beneficial comments (recommendations, additions, deletions) and any pertinent data wh
4、ich may be of use in improving this document should be addressed to: U.S. Army Natick Research and Development Center, Natick, E - Helmet, Parachutists , Sinall, Medium and Large; Type I Without Communication Equipment; Assembly Inner Shell and Outer Shell; Types I and II; Assembly - Helmet, Parachu
5、tists, Small, Medium and Large; Outer Shell; Types I and II; Assembly and Sections - Helmet, Parachutists, Small, Medium and Large; Inner Shell; Types I and 11; Assembly and Sections - Helmet, Parachutists; Types 1 and II; Patterns, Size Small - Helmet, Parachutists; Types I and II; Patterns, Size M
6、edium - Helmet, Parachutists; Types I and II; Patterns, Size Large - Helmet, Parachutists; Types I and II; liiscellaneous Patterns for Small and Nedium Sizes - Helmet, Parachutists, Small, Medium and Large; Type II with Communication Equipment; Assembly - Bracket, Microphone PE-l627/AIC Assembly - H
7、elmet, Parachutists, Small, Medium and Large; Types I and II; Chin Strap Details U.S. AIR FORCE 55C13289 - Bracket, Microphone, MT-l627/AIC, Assembly of 56E12858 - Cushion, Earphone, MS-2088/U; Assembly of 57C12630 - Bracket, Earphone Cushion, Electrical Xeadset 60C4459 - Receiver, Oxygen Flask; Ass
8、embly of (Copies of documents required by manufacturers in connection with specific acquisition functions should be obtained from the contracting activity or as directed by the contracting officer .) 2 /LI - - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
9、IHS-,-,- - - -I_- MIL-H-43174C 4 = 7777706 0372370 2 = MIL-H-43174C 2.2 Other publications. Unless otherwise specified, the following documents of the issue in effect on date of invitation for bids or request for proposal, form a part of this document to the extent specified herein. AMERICAN SOCIETY
10、 FOR TESTING AND MATEIALS (ASTM) D 3951 - Standard Practice for Commercial Packaging (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) (Technical society and technical association documents are generally availabl
11、e for reference from libraries. using Federal agencies.) They are also distributed among technical groups and * 2.3 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document shall take precedence . 3 . REQUIREMENTS 3.
12、1 Samples. 3.1.1 Guide samples. Samples, Ighen furnished re sol information to the contractor (see 6.3). Variation from - the samples, in which case the docuinent shall govern. ly for guidance and the document may appear in 3.1.2 Standard color samples. Unless otherwise specified, standard samples f
13、or color shall apply (see 6.3). 3.1.3 First article. When specified, a sample shall be subjected to first article inspection (see 4.3, 6.2 and 6.5). 3.2 Materials and components. Materials and components shall be as specified on the applicable drawings and as specified herein. For materials or compo
14、nents for which it is stated “or equal“, if the contractor proposes to use an item considered to be equal to the material or component specified, prior to its use the contractor shall furnish a sample of the material or component, with supporting data to the contracting officer for subsequent evalua
15、tion by the responsible military agency. 3.2.1 Instructions for use. An instructions for use sheet, of white paper, approximately 8-1/2 inches by 11 inches, shall be furnished with each helmet (see 5.1.1). The contents of the instruction sheet shall be as shown on figure 1. 3.3 Construction. The con
16、struction shall conform in all respects to-the drawings listed in 2.1 and as specified herein. 3.3.1 Stitching. Al1 stitching shall. be as specified on the applicable drawings and as specified herein. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,
17、-MIL-H-43174C 3.3.2 Thread tension. Thread tension shall be maintained so that there will be no loose stitching resulting in loose bobbin or top thread, or excessively tight stitching resulting in puckering of the materials sewn. in the materials sewn. The lock shall be embedded 3.3.3 Repairs of typ
18、e 301 stitching. Repairs of type 301 stitching shall be as follows : a. When a thread break or bobbin run-out occurs during sewing, the stitching shall be repaired by restarting the stitching a minimum of 1 inch back of the end of the stitching. i/ b. - Any thread break, two or more consecutive skip
19、ped stitches or runoff stitches noted during inspection of the item (in-process or end item) shall be repaired by overstitching. the defective area, continue over the defective area and continue a minimum of 1 inch beyond the defective area onto the existing stitching. tight stitching shall be repai
20、red by removing the defective stitching, without damaging the materials, and restitching in the required manner. i/ The stitching shall start a minimum of 1 inch in back of Loose or excessively - backstitched. O 3.3.4 Automatic stitching. Automatic machines may be used to perform any of the required
21、 stitch patterns provided the requirements for the stitch pattern, stitches per inch, size and type of thread are met, and at least three or more tying, overlapping or back stitches are used to secure the ends of the stitching. 3.3.5 Thread ends. Ail thread ends shall be trimmed to a length of not m
22、ore than 3.3.6 Setting of snap fasteners. A hole shall be prepunched to receive the button and eyelet components of the snap fasteners. the outside diameter of the button and eyelet barrels so that the barrel must be forced through the hole. The hole shall not be punched in the setting operation wit
23、h the button or eyelet barrel. cutting the adjacent materials. The hole shall be smaller than The fasteners shall be securely clinched without 3.3.7 Repairs. Fxcept as otherwise specified herein, repairs are not allowed to be made to the helmet. 3.3.8 Replacement of defective components. During the
24、spreading, cutting and manufacturing process, components having material defects or damages that are classified as defects in 4.4.3 shall be removed from production and replaced with non-defective and properly matched components. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted
25、 without license from IHS-,-,-MIL-H-43174C 3.3.9 Patterns. Standard patterns for the helmet components are shown full size on drawings and shall be used as a guide for cutting working patterns. patterns shall not be altered in any way and the working patterns shall conform exactly to the standard pa
26、tterns. The standard 3.3.10 Cutting of components. Components covered by a pattern shall be cut within +1/1C - 1/32 inch of the applicable pattern. 3.4 Communications equipment operation. After installation in the helmet, the communication equipment (headset microphone assembly) in the type II helme
27、t, shall function satisfactorily when tested as specified in 4.4.5. * 3.5 Fit. !3e assembled helmet shall fit snugly upon a standard head form when - tested as specified in 4.4.5. been used for previous contracts, shall be approved by the contracting officer prior to use (see 6.2). Head forms that m
28、ay be owned by a contractor and had 3.6 Workmanship. The helmet assembly shall conform to the quality of product established by this document and the occurrence of defects shall not exceed the applicable acceptable quality levels. 4. OUALIrJY ASSURANCE PROVISIONS 4.1 Responsibility for inspection. U
29、nless otherwise specified in the contract or purchase order, the contractor is responsible for the performance of all inspection requirements as specified herein. Except as otherwise specified in the contract or purchase order, the contractor may use his own or any other facilities suitable for the
30、performance of the inspection requirements specified herein, unless disapproved by the Government. inspections set forth in the document there such inspections are deemed necessary to assure supplies and services conform to prescribed requirements. The Government reserves the right to perform any of
31、 the 4.2 Classification of inspection. The inspection requirements specified herein are classified as follows : a. First article inspection (see 4.3). b. Quality conformance inspection (see 4.4) . 4.3 First article inspection. When a first article is required (see 6.2), it shall be examined for the
32、defects specified in 4.4.3 and 4.4.4. defect shall be cause for rejection of the first article. The presence of any 4.4 Quality conformance inspection. Unless otherwise specified, sampling for inspection shall be performed in accordance with MIL-STD-105. 4.4.1 Component and material inspection. In a
33、ccordance with 4.1, components and materials shall be inspected in accordance with all requirements of referenced documents unless otherwise excluded, amended, modified or qualified in this document or applicable purchase document . 5 Provided by IHSNot for ResaleNo reproduction or networking permit
34、ted without license from IHS-,-,-MIL-H-43174C 4.4.2 In-process inspection. Inspection of the helmet components during the manufacturing operations shall be made to ascertain that construction details which can not be examined on the finished product are in accordance with specified requirements. The
35、 in-process inspection shall include inspection of the working patterns to assure that they conform to the standard patterns, inspection of the cut parts covered by patterns to ascertain that the parts are cut properly with respect to size and material directional requirements and that the diameter
36、of the holes for the snap fasteners is smaller than the outside diameter of the button and eyelet barrels. Whenever non-conformance is noted, corrections shall be made to the components affected and lot in-process. removed from production. Parts which cannot be corrected shall be * 4.4.3 End item vi
37、sual examination. The end item shall be examined for the defects listed below. The lot size shall be expressed in units of one helmet assembly. The sample unit shall be one helmet assembly. The inspection level shall be II and the acceptable quality level (AQL), expressed in terms of defects per hun
38、dred units, shall be 2.5 for major defects and 10.0 for total (major and minor combined) defects. Classification Defect Najor Minor Color not uniform Any hole, cut, tear, or rip X Any needle chews x. Any abraded area X Grain surface not on outside X Not soft or pliable X Finish omitted, flaky, crack
39、ed or tacky X Flanky, spongy, or boardy X Any mend, darn, or patch X Any mend, darn, or patch X .Edges not seared X Any hole, cut, or tear Any hole, cut, or tear Broken or malformed, corroded area, Finish omitted or not as specified, Any required component improperly burr, or sharp edge where requir
40、ed installed causing failure to serve intended purpose 6 /I- *% A i; I X X X X X Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-H-43174C Classification Examine Defect Major Minor Snap fastener D-Ring Receiver, oxygen mask Ear cuchion(s) Pressure
41、 pads Reinforcements (outer shell) NOTE : Clinched excessively tight, cutting adjacent materials Clinched loosely, permitting any component to rotate freely but not to the degree that any component can be expected to become detached during use Clinched loosely to the degree that components can be ex
42、pected to become detached during use Incorrect style Orientation of button and socket components on chin strap not as specified Any fastener not functioning properly, i.e., fails to be snapped closed, provide a secure closure or to open freely The fasteners shall be snapped and unsnapped twice to de
43、termine whether parts of fastener separate freely and also effect a secure closure. Not type, style, or size specified Attaching screw(s) not securely One or more screws omitted Short screw used where long screw is required or vice versa tightened Any hole, cut, tear or abraded area Not hand tacked
44、to helmet as specified Two or more screws omitted Two screws loose Three or more screws loose Any omitted, cut or torn hy reinforcement omitted (check by feel) X x X X X X X X X X X X. X X X X X 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I
45、-43174C Classification Examine Defect Major Minor Communication equipment (type II helmet) : General Earphone(s) Connecting cord, earphone Microphone Microphone boom Plug, earphone connecting cord Seams and Stitching : Open seams NOTE : Seams and stitch type Any wire cut, cracked, or abraded Any har
46、dware component: - Corroded - Omitted - Not attached as specified Any component omitted Dirt or any foreign matter in earphone baffle holes Not routed as specified Any stitching passing through cord Cracked Not adjustable by hand Broken or deformed Will not adjust or swing when locking screw is loos
47、ened, or cannot be locked in set position Not secured to helmet as specified Any on leather component On materials other than leather: - One-half inch or less - More than 1/2 inch A seam shall be classified as open when one or more stitches joining a seam are broken or when two or more consecutive s
48、kipped or runoff stitches occur Incorrect seam or stitch type Any seam not flat and smooth X X X X X X X X X X X X X X X X 8 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Stitch tension NIL-H-43174C 4 = 7777706 0372376 3 = - MIL-H-43174C Classifica
49、tion Examine Defect Major Minor Stitches per inch NOTE : Thread breaks, skipped stitches, or runoffs NOTE : Stitching ends Rows of stitching Loose, resulting in loose top or Excessively tight, resulting in bobbin thread puckering of material One to two stitches less than minimum Three or more stitches less than TITO or more stitches in excess of specified minimum specified maximum specified Variation in
