MIL-DTL-25959 Tie Down, Tensioners, Cargo, AircraftThis specification covers two types of aircraft cargo tie down tensioners and excludes cargo chains. The tie down tensioners are considered to be aircraft Critical Safety Items \(CSI\). Type I \(10,000 lbs\) and Type II \(25,000 lbs\) cargo chains are governed under MIL-DTL-6458 and are procured separately from the tie down tensioners in this specification.

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MIL-DTL-25959H

3.8 Operation. Both types of tie down tensioners listed in this specification shall be capable of

being easily operated in worldwide environmental conditions (see 3.4). The tensioner tie downs

must function easily, and the release mechanisms shall be designed to allow one-handed

operation using a three or four finger grasp. Both functions must be easily performed by

personnel wearing aircrew cold weather work gloves (or mittens) or chemical/biological gloves

(or mittens). All mechanisms shall be manually operable without the use of tools or

supplementary devices. Positive locking shall be incorporated in the tensioning mechanism and

automatically engage upon completion of the tensioning operation. It shall be possible to

override the positive locking feature to gradually remove tension without releasing and

separating the chain. The mechanism shall be capable of one-handed tensioning and release by

one crewmember when tested as specified in 4.6.6.4.

3.9 Loads.

3.9.1 Proof loads. Tie down tensioners shall be capable of withstanding a proof load of 12,000

lbs for the CGU-8/A and 30,000 lbs for the CGU-7/A for 30 seconds without permanent

deformation or cracking. Additionally, no component of the tie down tensioner shall be

damaged or permanently deformed when torques of 85 inch-pounds are applied to the tensioning

adjustment control, in the tensioning direction while the tie down tensioner is fully retracted, or

in the loosening direction when in the fully extended position, when tested as specified in

4.6.7.1.

3.9.2 Axial torque loads. Tie down tensioners shall be capable of withstanding an axial torque

load of 2,000 inch-pounds for the CGU-8/A and 4,000 inch-pounds for the CGU-7/A in either

direction for 30 seconds without permanent deformation or damage when tested as specified in

4.6.7.2.

3.9.3 Ultimate loads. Tie down tensioners shall be capable of withstanding a sustained ultimate

load of 14,100 lbs for the CGU-8/A and 35,250 lbs for the CGU-7/A for 30 seconds without

failure when tested as specified in 4.6.7.3. During this test, part damage and deformation are

allowed, but complete rupture of the hardware or failure to withstand the load shall not be

permitted.

3.9.4 Maximum service load rating. The maximum allowable service load or max load rating for

safe operation is 10,000 lbs for the CGU-8/A and 25,000 lbs for the CGU-7/A tie down

tensioner.

3.9.5 Dynamic loads. The tie down tensioner shall be capable of withstanding dynamic loads up

to 10,000 lbs for the CGU-8/A and 25,000 lbs for the CGU-7/A. Contractors shall demonstrate

compliance with this requirement by testing in accordance with 4.6.7.4 and 4.6.7.5.

3.10 Interchange. All parts having the same manufacturer's part number shall be functionally

and dimensionally interchangeable.

3.11 Maintenance. The tie down tensioner shall not require periodic maintenance or adjustment

(other than lubrication every 5 years) to maintain its serviceability.