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

cracks with repeated use under normal operating conditions. The tie down tensioners shall be

constructed so as not to cause injury to operating personnel.

3.3.1 Materials and protective coatings.

3.3.1.1 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. However, used, rebuilt, or refurbished items shall

not be provided.

3.3.1.2 Protective coatings. Materials that deteriorate when exposed to sunlight, weather, or

operational conditions normally encountered during the service life (see 3.3.5) of the item shall

not be used or shall have means of protection against such deterioration that does not prevent

compliance with the performance requirements specified herein. Protective coatings that chip,

crack, or scale with age or extremes of climatic conditions or when exposed to heat shall not be

used. Fasteners, handles, and fittings used in the assembly of the item shall also be treated with

the proper corrosion preventatives.

3.3.1.3 Dissimilar metals. Dissimilar metals, as defined in MIL-STD-889, shall not be in contact

with each other. Metal plating or metal spraying of dissimilar base metals to provide

electromotively compatible abutting surfaces is acceptable. The use of dissimilar metals only

when separated by suitable insulating material is permitted, except in systems where bridging of

insulation materials by an electrically conductive fluid can occur. Sealants or gel type gasket

materials shall be used between faying surfaces and butt joints.

3.3.2 Markings. Equipment, assemblies, and parts shall be marked for identification in accordance

with MIL-STD-130. The contract number, contract date, date of manufacture, contractor part

number, national stock number (NSN), and classification are mandatory. The tie down tensioner

shall be marked to indicate the maximum service load rating specified in 3.9.4. These markings

shall be permanent.

3.3.3 System safety. The design of the tie down tensioner shall not contain any hazards that can

result in a category greater than medium as defined in Table III of MIL-STD-882. The tie down

tensioner shall be functional without sharp edges or burrs that might injure operational personnel

or prevent the operation of the tie down tensioners in restricted locations. Operation of the tie

down tensioner shall not present undue hazards to 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

down tensioners. Tie down tensioners shall be capable of being released using only one hand to

allow the tie down tensioner to be released in an emergency situation. Normal operation shall

not present cutting, pinching, stabbing, nor abrupt impact hazards to personnel or present a

tearing hazard to chemical/biological personal protective gear.

3.3.4 Fastening devices. All screws, bolts, nuts, pins, and other fastening devices shall be

properly designed, manufactured, and installed with adequate means of preventing loss of torque

or adjustment. Cotter pins, lock washers, or nylon patches shall not be used for this purpose,

except for the attachment of trim items or as provided in commercial components. The