Draft_-_Next_Gen_Cargo_Pallet_Replacement_MIL_DTL_27443.docx

DETAILED SPECIFICATION

PALLETS, CARGO, AIRCRAFT, TYPE HCU XXX, NEXT REVISION

USAF AFMC AFLCMC/WNZEB

235 Byron Street, Suite 19A Robins AFB GA 31098-1813

July 2016

DISTRIBUTION STATEMENT D: Distribution authorized to the Department of Defense and U.S. DoD contractors only (Critical Technology). Other requests shall be referred to AFLCMC/ WNZEB, 235 Byron Street, Suite 19A, Robins AFB, GA 31098-1813. .

Use or disclosure of data contained on this page is subject to the restriction on the cover page.

Table of Contents

List of Figures

1. SCOPE

1.1 Scope. Pallets, cargo, aircraft, covered by this specification have a capacity of 10,000 pounds.

1.2 Classification. Aircraft cargo pallets covered by this specification are of the following types: Type I - 10,000 pounds capacity designated HCU-XXX.

1.3 Part or Identifying Number (PIN). The PIN to be used for pallets acquired to this specification are created as follows:

M27443 - 1

Type 1

Specification

SPECIFICATION

DEPARTMENT OF DEFENSE

MIL-DTL-53022, Detail Specification: Primer, Epoxy Coating, Corrosion Inhibiting Lead and Chromate Free, Jan 2012.

MIL-DTL-27443F, Detailed Specification, Pallets, Cargo, Aircraft, Type HCU-6/E and HCU-112/E, 15 July 2003.

MIL-STD-1791, Designing for Internal Aerial Delivery in Fixed Wing Aircraft

STANDARDS

FEDERAL

FED-STD-595, Colors Used In Government Procurement PPP-B-601H, Federal Specification - Boxes, Wood, Cleated Plywood

DEPARTMENT OF DEFENSE

MIL-STD-130, Identification Marking of U.S. Military Property Ground and Ground Support Equipment MIL-STD-810G, Environmental Engineering Considerations and Laboratory Tests MIL-STD-889, Dissimilar Metals

HANDBOOKS

DEPARTMENT OF DEFENSE

MIL-HDBK-831, Preparation of Test Reports (Unless otherwise indicated, copies of the above specifications, standards, and handbooks are available from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)

2.2.2 Other Government drawings. The following other Government drawings form a part of this document to the extent specified herein. Unless otherwise specified, the issues are those cited in the solicitation.

DRAWINGS

USAF Dwg. Numbers:

201642455 – Pallet Assembly, Cargo – HCU-XXX, Next-Gen.

201642459 – Tie-Down Ring Assembly - Pallet, Airborne Cargo.

TECHNICAL ORDERS

TO 35D33-2-2-2, TECHNICAL MANUAL, INSTRUCTIONS WITH PARTS BREAKDOWN, 463L AIR CARGO PALLETS HCU-6/E, HCU-12/E, 15 July 2003.

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 which 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 (see 6.2).

AMERICAN SOCIETY FOR QUALITY (ASQ)

ANSI/ASQ Z1.4, Sampling Procedures and Tables for Inspection by Attributes (DoD adopted) (Application for copies should be addressed to the American Society for Quality, 600 North Plankinton Avenue Milwaukee, Wisconsin 53203.)

AMERICAN WELDING SOCIETY (AWS)

AWS D17.3, Specification for Friction Stir Welding of Aluminum Alloys for Aerospace Applications, 2010.

AWS B4.0, American Welding Society Standard Methods for Mechanical Testing of Welds, 2007.

INTERNATIONAL ORGANIZATION FOR STANDARDIZATION (ISO)

ISO 8256:2004, Plastics - Determination of Tensile-Impact Strength

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.

3.2.2.1 Dissimilar metals. Contact between dissimilar metals shall be avoided wherever possible (see 4.5.1). Wherever such contacts are unavoidable, they shall be insulated in a manner approved by the procuring activity. Dissimilar metals are defined in MIL-STD-889.

3.3 Construction. The pallet shall be constructed so that no parts shall work loose in service. It shall be built to withstand the strains, jars, vibration, and other conditions incident to shipping, storage, installation, and service (see 6.1). The pallet shall be constructed as an integral unit and shall not require assembly or attachment of separate parts during operational use. The pallet shall be constructed and assembled according to requirements herein and applicable USAF Dwg. No. 201642455.

3.4.1.1 Ring location and movement. Tie-down rings shall be provided according to the requirements herein and applicable drawing 201642459. When not used for tie-down, the rings shall not interfere with the entry of the pallet into a rail section. The pivot point of the ring shall be outside the usable surface edge. Each ring shall be capable of at least 225° of free movement in a vertical plane that intersects the pallet edge at right angles (see 4.5.3.1).

3.4.1.2 Ring capacity one. Each ring shall be designed to sustain a 7,500 pound tension load along any line in a vertical plane that intersects the pallet edge at right angles within the angular limits (see 4.5.3.2) without permanent deformation or other damage. The rings shall withstand 7,500 pounds x 1.5 (Safety Factor) = 11,250 pounds ultimate load without failure (deformation is acceptable after this test).

3.4.1.3 Ring capacity two. Each ring shall also be designed to sustain a 7,500 pound load along any line originating at the attachment point in a vertical plane extending above the pallet and parallel to the edge without permanent deformation or other damage (see 4.5.3.3).

3.4.1.4 Ring capacity three. The rings shall be designed such that two adjacent corner rings can be pulled simultaneously and then two center rings pulled simultaneously to a load of 7,500 pounds, without permanent deformation or other damage (see 4.5.3.4).

3.4.3.1 Corner lifting. When uniformly loaded (see 6.3.3), the pallet shall be capable of withstanding, without permanent deformation or other damage, lifting by means of 4 cables attached to the 4 tie-down rings adjacent to the 4 corners (see 4.5.5.1). Two separate tests shall be conducted: 1) the pallet shall be lifted by the corners tie-down rings on the long side and 2) the pallet shall be lifted by the corner tie-down rings on the short side.

3.4.3.2 Forklift lifting. When uniformly loaded to rated capacity (see 6.3.1), a pallet shall withstand lifting from a conveyor (see 3.4.4.1) without deformation or other damage. A forklift truck having 72 inch long by 6 to 8 inch wide tines spaced 42 inches center-to-center shall lift the pallets. Forklift truck tines shall have an end radius of not less than 0.250 inch (see 4.5.5.2).

3.4.3.3 Forklift “wedge” lifting. When uniformly loaded to rated capacity (see 6.3.1), a pallet shall withstand lifting from a smooth, dry, concrete surface without deformation or other damage. The tines shall be wedged under the pallet perpendicular to a pallet rail and lifted just using the lip of the pallet. A forklift truck having 72 inch long by 6 to 8 inch wide tines spaced 42 inches center-to-center shall lift the pallets. Forklift truck tines shall have an end radius of not less than 0.250 inch (see 4.5.5.3).

3.4.4 Traversable capabilities.

3.4.4.1 Conveyor. When uniformly loaded to rated capacity (see 6.3.1), the pallet shall be capable of traversing roller conveyors with 2-inch diameter by 3.5 inch long rollers spaced on 10 inch centers. The pallet shall be supported by four rows of conveyors, one row along each side, and one row along a line 10 inches each side of the center line (see 4.5.6.1). The pallet shall be capable of performing this testing without permanent deformation or other damage.

3.4.4.2 Conveyor ramp. When uniformly loaded to rated capacity (see 6.3.1), the pallet shall withstand being towed over a 17o, 10-foot long ramp connected to a single horizontal conveyor surface above the ramp. The pallet shall be supported by conveyors as specified (see 3.4.4.1). The pallet shall be towed parallel to both 88 and 108-inch sides for Next-Gen pallets (4.5.6.2). The pallet shall be capable of performing this testing without permanent deformation or other damage.

a. Temperatures ranging from -65o to +165o F (see 4.5.8.1, 4.5.8.2).

b. Humidity (see 4.5.8.3).

c. Salt-fog test (see.4.5.8.4)

3.4.7 Mechanical properties.

3.4.7.1 Point load. The surface of the pallet shall withstand 900 psi point loads (over one square inch) and in a location midway between the extrusion ribs, without permanent deformation (see 4.5.9.1).

3.8.1 Identification plate. Two identification plates which conform to A-A-50271 and are marked in accordance with MIL-STD-130 shall be attached to the pallet (see 4.5.1). The identification plates shall be of a size and shape consistent with the information required thereon. One plate shall be located above the locking lips on a long rail; the other shall be located above the locking lips on a short rail. The identification plates shall contain the following information:

MANUFACTURER'S FEDERAL SUPPLY CODE

MANUFACTURER'S SERIAL NUMBER

CONTRACT NUMBER

DATE OF MANUFACTURE

a. First article inspection (see 4.3).

b. Conformance inspection (see 4.4).

4.2 Test rejection criteria. Throughout all tests specified herein, the pallet shall be closely observed for the following conditions, which shall be cause for rejection:

a. Failure to conform to design or performance requirements specified herein.

b. Structural failure of any component, including permanent deformation, cracking, or evidence of impending failure.

c. Evidence of excessive wear.

d. Misalignment of components.

e. Conditions which present a safety hazard to personnel during operation, service or maintenance.

Examination of product (4.5.1) Tie-down ring test (4.5.3.1 through 4.5.3.4) Lifting capabilities tests (4.5.5.1 through 4.5.5.3) Environmental tests (4.5.8) Destruction analysis (4.5.9) Examination of product (4.5.1) Static load test (4.5.4) Traversable capabilities tests (4.5.6) Ultimate load test (4.5.7)

4.4.2.1 Lot. A lot shall consist of pallets manufactured under the same conditions and submitted for inspection at the same time.

4.4.2.2 Sampling. Sampling for examination and tests shall be in accordance with ANSI/ASQ Z1.4, general inspection level II, single sampling plan for normal inspection. AQL’s of zero for critical, 1.5% for major, and 4% for minor.

4.4.2.3 Examination. Samples selected in accordance with 4.4.2.2 shall be examined as specified (see 4.4.2.5).

4.4.2.4 Tests. Samples selected in accordance with 4.4.2.2 shall be tested as specified in 4.5.3.4, 4.5.5.1, and 4.5.9.2. Supplier shall present Statistical Process Control data, as well as qualitative and quantitative test data to demonstrate compliance with AWS D17.3, Class B for Friction Stir Welds during both process development and production. Samples to demonstrate compliance with 4.4.2.2 may include off-cuts, extractions, or witnesses. GMAW and GTAW quality for corner welds verified by: 1) 100% visual inspection; 2) sampling per 4.4.2.2 using off-cuts, extractions, or witnesses to verify weld integrity, as well as 4.5.3.4, and 4.5.9.2.

4.4.2.5 Classification of defects. All dimensional characteristics are considered defective when out of tolerance. The classification of defects for pallets shall be as follows:

Critical

1. Length, width, and lip dimensions out of tolerance.

2. Pallet not processed in accordance with approved process specification.

3. Failed lift test.

4. Flatness out of tolerance.

5. Weld gaps, weld cracks, or missing weld areas.

Major

1. Lock notches out of tolerance.

2. Tie-down ring fastening device not coated with wet primer when installed.

3. Tie-down ring missing.

4. Tie-down ring mounting hardware loose or located incorrectly.

5. Rivet missing.

6. Wrong rivets.

7. Tie-down rings assembly parts not plated in accordance with drawing.

8. Part not marked in accordance with MIL-STD-130.

9. Thickness exceeds tolerance.

10. Tie-down ring not coated as specified after installation.

Minor

1. Cocked rivet.

2. Weight exceeds maximum.

4.4.2.6. Rejection and retest. When a specified sample (see 4.4.2.2) from a lot fails to meet the specification, acceptance of all pallets in the lot shall be withheld until the extent and cause of failure have been determined. The contractor shall fully explain to the Government representative the cause of failure and the action taken to preclude recurrence. After correction of the lot, all of the sampling tests shall be repeated on one pallet from this lot.

4.4.2.6.1 Individual tests may continue. For production reasons, individual tests or other sampling plans may be continued pending the investigation of a sampling test failure. However, final acceptance of the entire lot shall not be made until it is determined that the lot meets all the requirements of the specification.

4.4.2.6.2 Defects in pallets already accepted. The investigation of a test failure could indicate that defects may exist in pallets already accepted. If so, the contractor shall fully advise the procuring activity of all the defects likely to be found and the method of correcting them.

4.4.3 Rejection and retest. When a pallet fails to meet the requirements of this specification, pallets to be delivered pursuant to the contract may not be accepted until the cause of the failure is determined, corrective action is taken by the contractor, and the components that failed are successfully retested to assure compliance with this specification. Tests not involving the failed component may be continued pending the investigation of a test failure.

4.5.3.1 Ring location and movement test. Compliance with the ring location and free movement requirements (see 3.4.1.1) shall be demonstrated for each ring.

4.5.3.2 Ring load test one. Two tie-down rings, one located at the pallet corner and the other located midway on the long side, shall be subjected to loading tests. In a plane that intersects the attachment point and is perpendicular to the pallet surface and edge, the ring shall be sequentially loaded to 7,500 pounds along lines that form 30°, 45°, 90°, 135°, and 180° with the upper pallet surface (see 3.4.1.2), see Figure 1. After the ring successfully passes these tests, it shall be loaded to 11,250 pounds (ultimate load = 7,500 x 1.5 = 11,250 pounds) along lines that form 90° and 180° with the upper pallet surface. 90° and 180° represent the worst-case orientation for the rings, since the rivets are in either pure shear or pure tension. For this ultimate load test, deformation of the tie-down ring assembly and rivet loosening are acceptable as long as the tie-down ring assembly remains attached to the pallet. Note that this 11,250 pound load case may be conducted using the test specimen from 4.5.8.4 (Salt Fog) to avoid damaging a serviceable pallet. The pallet (or test specimen from 4.5.8.4) shall be clamped down to a rigid surface for this testing. Loading of the ring may use a hook or clevis, with a load cell between the loading device and the hook or clevis with a minimum cross sectional area of 0.875 square inches.

FIGURE 1. Ring Tie-Down Test One (Isometric and Side Views)

4.5.3.3 Ring load test two. In a vertical plane that intersects the attachment point and is parallel to the pallet edge, a 7,500-pound load shall be applied sequentially in two directions parallel to the upper pallet surface and at 45° and 135° angles with this surface (see 3.4.1.3), see Figure 2.

FIGURE 2. Ring Tie-Down Test Two (Isometric and Side Views)

4.5.3.4 Ring load test three. The pallet shall be placed in a horizontal plane and two adjacent corner rings pulled simultaneously and then two center rings pulled simultaneously, see Figure 3. The load shall be 7,500 pounds. At the completion of the tests any permanent deformation or cracking of the pallet or tie-down rings shall be cause for rejection. The load during each test shall be applied for not less than 3 times each (see 3.4.1.4).

FIGURE 3. Ring Tie-Down Test Three

4.5.5.1 Corner hoist test. Corner hoist tests shall be conducted with a clevis or hook with a minimum cross sectional area of 0.875 square inches. The pallet shall be completely raised off the floor (see 3.4.3.1), held in that position for 1 minute, and then returned to the floor. This procedure shall be repeated 10 times. For sample testing, the test load procedure shall be reduced on each test sample to 2 times. During the test, any separation of the mitered corners shall be cause for rejection. Upon completion of the test, evidence of permanent deformation, weld separation, or other weld failures shall be cause for rejection (see 3.4.3.1). Testing shall be conducted on the four corner rings on the long rails and then the four corner rings on the short rails.

4.5.5.2 Forklift lifting test. The pallet shall be raised according to (see 3.4.3.2) to a height of 1 foot and held 1 minute, then lowered to rest on the conveyor. This procedure shall be repeated 10 times. Upon completion of the test, evidence of permanent deformation, weld separation, or other weld failures shall be cause for rejection.

4.5.5.3 Forklift “wedge” lifting test. The pallet shall be raised according to (see 3.4.3.3) until it clears the floor. The pallet shall then be lowered to the floor and forklift tines withdrawn. This test shall be conducted 5 times from each side of the pallet. Upon completion of the test, evidence of permanent deformation, weld separation, or other weld failures shall be cause for rejection.

4.5.6 Traversable capabilities tests.

4.5.6.1 Conveyor test. According to (see 3.4.4.1), the pallet shall be subjected to the following tests. Upon completion of the test, evidence of permanent deformation, weld separation, or other weld failures shall be cause for rejection.

a. The pallet shall be moved a minimum of 10,000 feet in a direction parallel to the 108-inch dimension at a minimum speed of 30 feet per minute (fpm). Any increment of movement shall be a minimum of 25 feet.

b. The pallet shall be moved a minimum of 15,000 feet in a direction parallel to the 88-inch dimension at a minimum speed of 30 fpm. Any increment of movement shall be a minimum of 25 feet.

4.5.6.2 Conveyor ramp test. According to (see 3.4.4.2), the pallet shall be towed up and over a 17o 10-foot long conveyor ramp connecting a single horizontal conveyor above the ramp. The pallet shall then travel back over the ramp. This procedure shall constitute one cycle. The pallet will be pulled/towed with a cable parallel to the upper horizontal conveyor that is attached to the pallet by only 2 rings. Attachment and winching procedures shall be per MIL-STD-1791 as shown in Figure 4. Throughout this test, the minimum towing speed of the pallet shall be 20 fpm. This test shall be repeated 30 cycles, 10 cycles in a direction parallel to the longest dimension and 20 cycles in a direction parallel to the shortest dimension. The ramps shall be constructed of roller conveyors as specified (see 3.4.4.1). Any permanent deformation or cracking of the pallet shall be cause for rejection.

FIGURE 4. Ring Attachment Procedure

4.5.8.1 High temperature test. The pallet shall be subjected to high temperature in accordance with procedure I guidelines, method 501.5 of MIL-STD-810G. After a 24-hour soak period at 165oF, the pallet shall be loaded with a flexible, uniformly distributed load (see 6.3.1) and subject to 50 consecutive cycles of loading as follows without permanent deformation. One cycle shall have a maximum duration of 30 seconds (see 3.4.6).

a. Lift the pallet completely off the floor by four tie-down rings located adjacent to the corners on the 88-inch sides. Lifting shall be conducted with a clevis or hook with a minimum cross sectional area of 0.875 square inches.

b. Lower the pallet to rest on three 4 x 4 x 88 inch long supports equally spaced and aligned with the short centerline. The lifting device shall be completely free of weight support while the pallet is at rest on the supports.

4.5.8.2 Water penetration and low temperature test. MIL-STD-810G, Method 512.5, Procedure 1, for immersion modified as follows: The pallet shall be subjected to the following immersions in the sequence listed (see 3.4.6):

a. Immerse 30 minutes in water at room temperature; the upper surface of the pallet shall be covered by at least 2 feet of water.

b. Remove from water and weigh pallet immediately.

c. Soak in a cold chamber for 4 hours at -65oF.

d. While the temperature remains at -65oF, the pallet shall be subjected to 20 cycles of the same lift test specified (see 4.5.8.1).

e. Repeat steps a through d.

The pallet shall survive the test without a structural failure or cracking.

4.5.8.3 Humidity test. The pallet shall withstand exposure to rain in accordance with Procedure II guidelines, Method 507.5 of MIL-STD-810G. This test shall be considered qualified by similarity with current pallet, since the Next-Gen pallet is all aluminum and has eliminated the adhesives, sealants, and balsawood used in the historic 463L pallet.

4.5.8.4 Salt fog test. The pallet shall be subjected to salt fog in accordance with Method 509.5, of MIL-STD-810G. Duration of exposure shall be 24 hours. Test shall be repeated for 4 cycles (see 3.4.6). A representative portion of the pallet may be used for this test as long as it includes examples of all weld types as well as the tie-down ring assemblies. This specimen may then also be used for other testing as appropriate.

4.5.9 Destruction analysis.

4.5.9.1 Pressure/Point Load Test. Each test sample shall be cut up. The specimen shall be 10 x 10 inches including three full extrusion cells, using those cells that have the thinnest outer skin dimensions. All parts of the pallet shall be permanently identified. The tests shall be as follows:

Using a 1 inch square steel mandrel, apply a 900-pound load to the top surface of one 10 x 10 inch test panel. The load shall be applied at the mid-point of the specimen centered in the open extrusion bay (midway between vertical webs). At the option of the supplier, the corners of the mandrel may be slightly rounded. The test panel may be from either test pallet number 1 or 2. The test specimen shall withstand the 900-pound load. Permanent deformation of the test panel in the load area shall not exceed 0.005 inch in depth. Deflection while under load shall be measured, but there is no specific elastic deformation limit. (Note this test may be conducted on a sample that is directly from an extrusion cutoff as opposed to being cut or extracted from a full pallet.)

4.5.9.2 Weld Testing. The manufacturer shall conduct Friction Stir Welding (FSW) process development and perform welding in accordance with AWS D17.3, Class B. FSW testing shall be conducted on representative samples from each type of joint and weld process, using representative manufacturing processes and materials. Two FSW configurations shall be tested: the longitudinal axis joint (long weld across top/bottom joining middle panels and edge panels) and the edge rail joint (top/bottom joining the edge rails to the edge panels and middle panels). For GMAW/GTAW corner specimens, samples shall be constructed using the top and bottom diagonal joints. Samples shall be tested 1 inch after start of weld and 1 inch before end of weld for both weld configurations. These shall be removed from actual pallets, off-cuts, or representative witness samples. Test coupons shall be cut to allow qualitative inspection of weld quality (cross-sections/micrographs allowing inspection for discontinuities). Prototype manufacture shall not commence until weld qualitative assessments are complete without unacceptable defects. Note that defect and strength requirements may be relaxed if quantitative testing is conducted and approved by the government demonstrating that the proposed requirements do not result in strength reductions below those specified and do not affect other critical test capability (such as 4.5.3.4). In lieu of the AWS D17.0 test coupons, test coupons in accordance with “American Welding Society (AWS B4.0:2007) Standard Methods for Mechanical Testing of Welds”, may be substituted. The test specimen shall be the ‘transverse rectangular tension specimen (plate)’. Where that geometry is not possible due to pallet geometry, other suitable specimens may be substituted. For example, for GMAW/GTAW specimens from the top and bottom surface diagonal corner welds, ISO8256, Type III specimens have been used successfully. Five specimens shall be tested for each type of weld process and for the as-extruded base material. GMAW/GTAW weld cross sections shall be inspected using the same criteria used for FSW. For GMAW/GTAW specimens, the average weld efficiency (weld specimen failure stress/parent extruded base material specimen failure stress) x 100% shall be greater than 33%. For FSW specimens, the average weld efficiency (weld specimen failure stress/ parent extruded base material specimen failure stress) x 100% shall be greater than 66%.

6. NOTES

(This section contains information of a general or explanatory nature which may be helpful, but is not mandatory.)

a. Title, number, and date of the specification.

b. Issue of DoDISS to be cited in the solicitation, and if required, the specific issue of individual documents referenced (see 2.2).

c. Type required (see 1.2).

d. Packaging requirements (see 5.1).

Use or disclosure of data contained on this page is subject to the restriction on the cover page.

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