1、 INCH-POUND MIL-PRF-27260D 26 June 2013 SUPERSEDING MIL-PRF-27260C 28 November 1998 PERFORMANCE SPECIFICATION TIE DOWN, CARGO, AIRCRAFT, CGU-1/B This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers one type
2、 of flight safety critical aircraft cargo tie down assembly. The tie down has been designated CGU-1/B with a 5,000-pound capacity and is furnished in a minimum length of 240 inches. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified in sections 3, 4, or 5 of this
3、 specification. This section does 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 this list, document users are cautioned that they must meet all specified req
4、uirements of documents cited in sections 3, 4, or 5 of this specification, whether or not they are listed. Comments, suggestions, or questions on this document should be addressed to AFLCMC/ENRS, 2145 Monahan Way, Bldg 28, Wright-Patterson AFB OH 45433-7017 or e-mailed to AFLCMC.ENEZ.Engineering.Sta
5、ndardswpafb.af.mil. Since contact information can change, you may want to verify the currency of this address information using the ASSIST Online database at https:/assist.dla.mil. AMSC N/A FSC 1670 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot
6、for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-27260D 2 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwi
7、se specified, the issues of these documents are those cited in the solicitation or contract. DEPARTMENT OF DEFENSE STANDARDS MIL-STD-130 Identification Marking of US Military Property MIL-STD-810 Environmental Engineering Considerations and Laboratory Tests (Copies of these documents are available o
8、nline 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 form a part of this document to the extent specified herein. Unless otherwise specified, the iss
9、ues of these documents are those cited in the solicitation or contract. AMERICAN SOCIETY FOR QUALITY (ASQ) ANSI/ASQ Z1.4 Sampling Procedures and Tables for Inspection by Attributes (DoD Adopted) (Copies of this document are available online at http:/www.asq.org or from the American Society for Quali
10、ty, 600 North Plankinton Avenue, Milwaukee, WI 53203.) RTCA RTCA/DO-160 Environmental Conditions and Test Procedures for Airborne Equipment (Copies of this document are available online at http:/www.rtca.org or from RTCA Inc., 1828 L Street, NW, Suite 805, Washington, DC 20036.) 2.4 Order of precede
11、nce. Unless otherwise noted herein or in the contract, in the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption h
12、as been obtained. 3. REQUIREMENTS 3.1 Qualification. The tie downs furnished under this specification shall be products that are authorized by the qualifying activity for listing on the applicable qualified products list before contract award (see 4.2 and 6.3). 3.2 Recycled, recovered, or environmen
13、tally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent possible, provided that the material meets or exceeds the operational and maintenance requirements, and promotes economically advantageous life cycle costs. Provided by IHSNo
14、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-27260D 3 3.3 Materials. All materials shall be treated to resist corrosion due to electrolytic decomposition, fungus, salt spray, and any other atmospheric conditions that may be encountered during operational u
15、se or storage (see 4.6). The use of toxic chemicals, hazardous materials, or ODCs shall be avoided. 3.4 Design. The tie down assembly shall be designed as an integral unit and shall not require attachment or assembly of separate parts for operation. The tie down assembly shall be designed so that no
16、 parts become loose while in service. The tie down assembly shall be designed so that, no portions of the tie down, which bear on the strap when in the operating position, shall not incorporate knurled, serrated, or other types of surfaces that would degrade the strap strength. The tie down shall be
17、 designed to allow easy operation by aircrew and ground support personnel while wearing standard work gloves (see 4.6). The tie down assembly shall be operable without the use of tools. 3.5 Components. The tie down major components shall consist of a strap, a fixed hook assembly, and an adjustable h
18、ook assembly that has an integrated adjusting, tensioning and release mechanism (see 4.6) as shown on Figure 1. FIGURE 1. CGU-1/B tie down assembly. 3.5.1 Strap. The strap shall incorporate a stop to prevent it from threading loose through the adjustable hook assembly as shown on Figure 2. The strap
19、 shall not have frayed ends (see 4.6). The strap shall not interfere with the operation and locking of the tensioning mechanism. FIGURE 2. CGU-1/B strap. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-27260D 4 3.5.2 Fixed hook assembly. The
20、fixed hook assembly shall have a non-swiveling hook with a mechanism on the hook to prevent inadvertent disengagement (see 4.6 and 4.7.1.3) as shown on Figure 3. FIGURE 3. CGU-1/B fixed hook assembly. 3.5.3 Adjustable hook assembly. The adjustable hook assembly shall have a non-swiveling hook, witho
21、ut an inadvertent disengagement mechanism (see 4.6) as shown on Figures 4 and 5. FIGURE 4. CGU-1/B adjustable hook assembly and tensioning mechanism. 3.6 Interface. 3.6.1 Tie down dimensions. The overall dimensions of the tie down are shown on Figure 5. 3.6.2 Hook dimensions. The hooks shall permit
22、insertion of the tie down to aircraft tie down rings having a minimum clear opening of 0.75 inch diameter and a maximum cross section diameter of 0.875 inch (see Figure 5). 3.6.3 Weight. The overall weight of the tie down assembly shall not exceed 3.75 pounds (see 4.6). 3.6.4 Strap color. The color
23、of the strap shall be natural white (see 4.6). 3.7 Operation. The fixed hook assembly and the adjustable hook assembly shall attach to the aircraft tie down rings (see 3.6.2) without the use of tools or other supplementary devices. The adjusting, tensioning, and release mechanism requirements (see 3
24、.8.3, 3.8.4, and 3.8.6) shall be accomplishable by aircrew and ground support personnel wearing standard work gloves. The Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-27260D 5 work gloves shall not cause interference with the operation of
25、the tensioning and release mechanism (see 4.7.1.1). 3.8 Performance. 3.8.1 Proof load. The tie down shall be capable of withstanding a proof load of 5,000 pounds for 30 seconds without slippage of the strap through the adjustment device. Damages such as broken stitching, torn or frayed strap, and de
26、formation or rupture of hardware shall not be permitted. The tie down shall be fully operational at the completion of this test (see 4.7.4). 3.8.2 Ultimate load. The tie down shall be subjected to an ultimate load of 6,000 pounds for 30 seconds. Damage such as broken stitching without complete separ
27、ation, torn or frayed strap without complete separation of the strap, and deformation but not rupture of hardware will be permitted. The release mechanism shall be operable at the completion of this test (see 4.7.4.1). 3.8.3 Adjusting mechanism. The tie down strap shall be capable of allowing the st
28、rap to be freely adjusted to any length within the limits as shown on Figure 5. It shall be possible to accomplish preliminary adjustments of the strap to the approximate length required in a maximum of 15 seconds. There shall be no inadvertent disengagement of the fixed hook assembly while securing
29、 the cargo (see 4.7.1.2). 3.8.4 Tensioning mechanism. The tensioning mechanism shall be of the progressive take-up-ratchet type or similar mechanism and shall be capable of taking up a minimum of one foot of strap The tensioning mechanism shall be capable of applying a tension of not less than 150 p
30、ounds using an applied force not to exceed 50 pounds. No more than seven progressive take-ups shall be required to obtain 150 pounds of tension with 18 feet of strap between the hooks. The mechanical advantage of the mechanism shall not exceed a ratio of 5:1 in the tightened position; the tensioning
31、 mechanism shall lock in accordance with Figure 5, running approximately parallel with the hook. A lock shall be incorporated in the tensioning mechanism and shall automatically engage upon completion of the tensioning operation. The force required to disengage the lock shall not exceed 5 pounds (se
32、e 4.7.1.2). 3.8.5 Tensioning mechanism strength. The tensioning mechanism shall be capable of withstanding a minimum applied force of 300 pounds without permanent deformation or malfunctioning of the mechanism. The tensioning mechanism shall be operable after completion of the test (see 4.7.1.2.1).
33、3.8.6 Release mechanism. The release mechanism shall release the tensioning mechanism when actuated and shall produce sufficient slack in the strap to permit removal of the attachment hooks from the tie down rings. It shall be possible to manually release a tension load of 750 pounds with the applie
34、d force not exceeding 60 pounds (see 4.7.1.3). 3.8.7 Strap strength. The strap shall have a minimum tensile strength of 9,500 pounds (see 4.7.2). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-27260D 6 3.9 Environmental conditions. The tie d
35、own shall be capable of satisfactory operation in various worldwide environmental conditions expected to be encountered during aircraft loading and unloading operations and long term storage to include the following conditions: a. Fungus growth as may be encountered in tropical climates (see 4.7.3.1
36、). b. Humidity of 100% (see 4.7.3.2). c. Salt spray as may be encountered in a salt sea atmosphere (see 4.7.3.3). d. Exposure to blowing sand and dust as may be encountered in desert regions (see 4.7.3.4). e. Vibration incident to service use (see 4.7.3.5). f. A minimum low temperature of -65 F (see
37、 4.7.3.6). g. A maximum high temperature of 160 F (see 4.7.3.7). h. Solar radiation as may be encountered in hot climates or from direct exposure to sunlight, showing no signs of degradation (see 4.7.3.8). 3.10 Durability. The tie down shall be designed to perform in its intended environment (see 3.
38、9) for a minimum of 30 years continuous use with no loss of function or safety (see 4.7.5). 3.11 Interchangeability. All parts having the same manufacturers part number shall be functionally and dimensionally interchangeable (see 4.6). 3.12 Item identification. The tie down major components (strap,
39、fixed hook, and adjustable hook assemblies) shall be permanently marked for identification in accordance with MIL-STD-130. The identification shall include the contract number, vendor, and contractor CAGE code (see 4.6). The following special marking shall be included: 5000 Lb. CAP (see 4.6). 3.13 S
40、afety. The tie downs shall be functional without sharp edges, burrs, or protrusions that might injure personnel or prevent the safe operation of the tie downs in areas of the aircraft with limited access or movement. Operation of the tie down assembly shall not present undue hazards to aircrew and g
41、round support personnel during tie down of cargo while the cargo is secured, during the release of cargo restraint, or during removal or stowage of the tie downs. Normal operation shall not present cutting, pinching, stabbing, nor abrupt impact hazards to personnel. Tie down straps shall not have de
42、fects such as holes, cuts, tears, splices, or abrasions which may cause strap failure and result in injury to personnel or damage to cargo. The strap shall also be free of grease, oil, dirt, or any other foreign matter that is not removable without damaging the strap and degrading its strength (see
43、4.6). 3.14 Toxic chemicals, hazardous substances, and ozone depleting chemicals (ODCs). The use of toxic chemicals, hazardous substances, or ODCs shall be avoided (see 4.6). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-27260D 7 4. VERIFICA
44、TION 4.1 Classification of inspections. The inspection requirements specified herein are classified as follows: a. Qualification inspection (see 4.2). b. Conformance inspection (see 4.3). 4.1.1 Sampling for inspection. Unless otherwise specified, sampling shall be in accordance with ANSI/ASQ Z1.4. 4
45、.2 Qualification inspection. Qualification inspection shall be performed on three complete tie down assemblies (A, B, and C). The three tie down assemblies will be visually examined as specified in 4.6. The three complete tie down assemblies will then be subjected to the tests as specified in 4.7, i
46、n accordance with the sequence specified in Table I (see 4.7). TABLE I. Testing sequence. Test Paragraph Test Article A Test Article B Test Article C 4.7.1 4.7.1.3 1 4.7.1.2 6 4 4.7.1.3 7 5 4.7.2 (strap only) 6 4.7.3.1 2 4.7.3.2 5 4.7.3.3 3 4.7.3.4 4 4.7.3.5 1 4.7.3.6 2 4.7.3.7 3 4.7.3.8 2 4.7.4 3 4
47、.7.4.1 4 4.7.5 1 4.3 Conformance inspection. Conformance inspection shall include the inspections (see 4.6) and the tests as specified in 4.7.1 to 4.7.1.3. 4.4 Test conditions. Unless otherwise specified, all inspections shall be performed in accordance with the test conditions specified in RTCA/DO-
48、160 for the applicable test. 4.5 Requirements cross-reference matrix. Table II provides a cross-reference matrix of the Section 3 requirements tested or verified in the paragraphs below. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-27260D
49、8 TABLE II. Requirements cross-reference matrix. Requirement Verification Requirement Verification 3.3 4.7.3.1 4.7.3.2 3.8.1 4.7.4 4.7.4.1 3.4 4.6 3.8.2 4.7.4.1 3.5 4.6 3.8.3 4.7.1.2 3.5.1 4.6 3.8.4 4.7.1.2.1 3.5.2 4.6, 4.7.1.3 3.8.5 4.7.1.2.1 3.5.3 4.6 3.8.6 4.7.1.3 3.6 4.6 3.9 4.7.3.1 4.7.3.8 3.6.1 4.6 3.10 4.7.5 3.6.2 4.6 3.11 4.6 3.6.3 4.6 3.12 4.6 3.6.
