This part of ISO 16049 specifies the design criteria and testing methods applicable to air cargo restraint straps to be used for tie-down of unitized or non-unitized cargo on board civil transport aircraft. It aims at identifying the design criteria and testing methods adequate to guarantee the ultimate load and operational dependability of cargo restraint strap assemblies with a typical 22 250 N (5 000 lbf) rated ultimate tension load capability, as used by the airline industry in order to restrain, on board civil transport aircraft during flight:

• cargo loaded and tied down on to airworthiness certified air cargo pallets, themselves restrained into aircraft lower deck or main deck cargo systems meeting the requirements of ISO 8097 (NAS 3610), or
• non-unitized individual pieces of cargo, or pieces of cargo placed on to an unrestrained (“floating”) pallet into either lower deck or main deck containerized cargo compartments of an aircraft.

The same restraint strap assemblies can also be used in other applications such as:

• non-containerized (bulk loaded) baggage and cargo compartments,
• to ensure cargo restraint inside an airworthiness certified air cargo container.

This part of ISO 16049 describes the design criteria for individual restraint strap assemblies, but does not intend specifying in any manner the way they are to be used aboard aircraft to ensure proper restraint throughout the certified flight envelope. It is important that tie-down arrangements meet all the applicable requirements of the Airworthiness Authorities approved Weight and Balance Manual for the aircraft type or sub-type concerned, particularly as regards, but not necessarily limited to, ultimate load factors to be taken into account to determine the number of straps to be used in each direction of restraint, maximum angles to be observed with the direction of restraint, minimum spacing of attachment points, etc.

When restraint strap assemblies are attached to the edge rails of a certified air cargo pallet meeting the requirements of ISO 8097, operating instructions should duly take into account the restraint net attachment point locations on the pallet edge rail and other requirements defined by the appropriate ISO 8097 configuration drawing(s).

The use of reliable and guaranteed restraint strap assemblies does not alone ensure flight safety: it also requires straps to be used and tie-down to be performed in accordance with operating instructions established by the aircraft manufacturer, by competent, suitably trained, personnel as defined in 4.18 of ISO 9002:1994.

Subject to proper operating instructions in accordance with 1.3 and 1.4, using unit restraint strap assemblies manufactured to an adequate design and a tested ultimate load capability is nevertheless deemed necessary in order to ensure flight safety. Although restraint straps are not formally subject to airworthiness certification, they serve an equivalent purpose and must be designed, fabricated, tested and used with equivalent precautions: this part of ISO 16049 is intended to allow manufacturer's self-certification under an approved ISO 9000 series, or equivalent, quality control programme.