MIL-DTL-6458 Chain Assemblies, Single Leg, Aircraft Cargo Tie DownThis specification covers two types of flight safety critical aircraft cargo tie down chain assemblies. The chains described in this specification are to be used in conjunction with the tie down tensioners described in MIL-DTL-25959, where the Type I chain assembly is to be used with the Type I \(styles A and B\) and Type III tie down tensioners, and the Type II chain assembly is to be used with the Type II \(styles A and B\) and Type IV tie down tensioners.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20

MIL-DTL-6458G

3.3 Chain assembly. The chain assembly shall be of the welded-link type consisting of a

length of chain, a coupling link, and a hook constructed so that it forms a single unit without

detachable parts. The weld on each link shall not interfere with attaching that link to or removing

it from the adjuster tumble block (i.e. no sharp edges extending beyond links). Each link shall be

capable of being attached to and removed from the adjuster tumble block, with a load applied,

without the use of special tools. The chain assembly shall meet the strength, weight and

dimensional requirements specified on figure 1.

3.4 Hook. The hook shall be a grab type with dimensions as shown in figure 2 and shall

engage chain links of the size specified on figure 1. The hook shall be designed to permit

fastening of one chain assembly to another of the same type to form a single branch system of

two chain assemblies for extension purposes. The hooks shall meet the design strength

requirements of the chain assemblies and shall not reduce the strength of the chain assembly into

which it has been attached. The hook must fully engage the attaching chain link with the chain

link in contact with radius R as specified on figure 2 and without interference from adjoining

links.

3.5 Recycled, recovered, or environmentally 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.

3.6 Performance.

3.6.1 Proof load. When tested as specified (see 4.5.2 and 4.5.8), the Type I chain assembly

shall be capable of withstanding proof loads of 10,000 pounds, and the Type II chain assembly

shall be capable of withstanding proof loads of 25,000 pounds. There shall be no evidence of

failure, permanent deformation or subsequent malfunction of parts.

3.6.2 Ultimate load. When tested as specified (see 4.5.3), the Type I chain assembly shall

be capable of withstanding ultimate loads of 14,100 pounds and the Type II chain assembly shall

be capable of withstanding ultimate loads of 35,250 pounds. Deformation, without rupture or

visible cracks, will be permitted provided the chain remains flexible after removing the applied

load.

3.6.3 Environmental characteristics. The chain assembly shall be fully operational and

show no evidence of rust or corrosion when subjected to the salt fog (spray) testing (see 4.5.5)

and the sand and dust testing (see 4.5.7). Any evidence of rust or corrosion will require an

additional proof load test as specified in 4.5.8.

3.7 Interchangeability. All parts having the same manufacturer's part number shall be

functionally and dimensionally interchangeable.