ISO 16049-1:2013
(Main)Air cargo equipment — Restraint straps — Part 1: Design criteria and testing methods
Air cargo equipment — Restraint straps — Part 1: Design criteria and testing methods
ISO 16049-1:2013 specifies the design criteria and testing methods adequate to guarantee the ultimate load and operational dependability of cargo restraint strap assemblies with a typical rated ultimate tension load capability of 22 250 N (5 000 lbf), as used by the airline industry in order to restrain on board civil transport aircraft during flight: a) cargo loaded and tied down onto airworthiness approved air cargo pallets, themselves restrained into aircraft lower deck, main deck or upper deck cargo systems and meeting the requirements of ISO 8097 (NAS 3610) or ISO 21100, or b) non-unitized individual pieces of cargo, or pieces of cargo placed onto an unrestrained ("floating") pallet into either lower deck, main deck or upper deck containerized cargo compartments of an aircraft. The same restraint strap assemblies can also be used in other applications such as: c) non-containerized (bulk loaded) baggage and cargo compartments, d) to ensure cargo restraint inside an airworthiness approved air cargo container. Compliance with ISO 16049-1:2013 provides one means of cargo restraint straps airworthiness approval by Civil Aviation Authorities under TSO/ETSO C-172, in addition to the other requirements therein.
Équipement pour le fret aérien — Sangles d'arrimage — Partie 1: Critères de conception et méthodes d'essai
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 16049-1
Second edition
2013-03-15
Air cargo equipment — Restraint
straps —
Part 1:
Design criteria and testing methods
Équipement pour le fret aérien — Sangles d’arrimage —
Partie 1: Critères de conception et méthodes d’essai
Reference number
ISO 16049-1:2013(E)
©
ISO 2013
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ISO 16049-1:2013(E)
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ii © ISO 2013 – All rights reserved
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ISO 16049-1:2013(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Design criteria . 6
4.1 General . 6
4.2 Ultimate load . 6
4.3 Elongation . 7
4.4 Flammability . 8
4.5 Environmental degradation . 8
4.6 Dimensions . 8
4.7 Tensioning device . 8
4.8 End fittings . 9
4.9 Webbing and sewing .10
4.10 Detailed design .10
5 Testing methods .11
5.1 Tests .11
5.2 Objective .11
5.3 Test specimens .11
5.4 Testing apparatus .11
5.5 Ultimate load test .12
5.6 Elongation test .13
5.7 Cyclic load test .13
5.8 Flammability test .14
5.9 Webbing elongation test (optional) .14
5.10 Webbing abrasion test (optional) .14
5.11 Test record .15
6 Quality control .15
7 Markings .16
8 Options .17
9 Manufacturer’s instructions .18
10 Operating instructions .18
Bibliography .19
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ISO 16049-1:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 9, Air cargo and ground equipment.
This second edition cancels and replaces the first edition (ISO 16049-1:2001), which has been
technically revised.
ISO 16049 consists of the following parts, under the general title Air cargo equipment — Restraint straps:
— Part 1: Design criteria and testing methods
— Part 2: Utilization guidelines and lashing calculations
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ISO 16049-1:2013(E)
Introduction
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.
Throughout this part of ISO 16049, the minimum essential criteria are identified by use of the key word
“shall”. Recommended criteria are identified by use of the key word “should” and, while not mandatory,
are considered to be of primary importance in providing safe restraint straps. Deviation from
recommended criteria should only occur after careful consideration, extensive testing, and thorough
service evaluation have shown alternative methods to be satisfactory.
The requirements of this part of ISO 16049 are expressed in the applicable SI units, with approximate
inch-pound units conversion between brackets for convenience in those countries using that system.
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INTERNATIONAL STANDARD ISO 16049-1:2013(E)
Air cargo equipment — Restraint straps —
Part 1:
Design criteria and testing methods
1 Scope
This part of ISO 16049 specifies the design criteria and testing methods adequate to guarantee the
ultimate load and operational dependability of cargo restraint strap assemblies with a typical rated
ultimate tension load capability of 22 250 N (5 000 lbf), as used by the airline industry in order to
restrain on board civil transport aircraft during flight:
a) cargo loaded and tied down onto airworthiness approved air cargo pallets, themselves restrained
into aircraft lower deck, main deck or upper deck cargo systems and meeting the requirements of
ISO 8097 (NAS 3610) or ISO/PAS 21100, or
b) non-unitized individual pieces of cargo, or pieces of cargo placed onto an unrestrained (“floating”)
pallet into either lower deck, main deck or upper deck containerized cargo compartments of an aircraft.
The same restraint strap assemblies can also be used in other applications such as:
c) non-containerized (bulk loaded) baggage and cargo compartments,
d) to ensure cargo restraint inside an airworthiness approved air cargo container.
NOTE The ultimate loads allowable on the attachment points available in most aircraft bulk compartments
and inside most air cargo containers are significantly lower than 22 250 N (5 000 lbf). This results in the restraint
arrangement’s ultimate load capability being dictated by the weakest element, i.e. the attachment points. Typical
22 250 N ultimate load restraint straps will therefore be in excess of the requirements for such applications.
Compliance with this part of ISO 16049 provides one means of cargo restraint straps airworthiness approval
by Civil Aviation Authorities under TSO / ETSO C-172, in addition to the other requirements therein.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 4117, Air and air/land cargo pallets — Specification and testing
ISO 4171, Air cargo equipment — Interline pallets
ISO 7166, Aircraft — Rail and stud configuration for passenger equipment and cargo restraint
ISO 8097, Aircraft — Minimum airworthiness requirements and test conditions for certified air cargo unit
1)
load devices
ISO/TR 8647, Environmental degradation of textiles used in air cargo restraint equipment
ISO 9788, Air cargo equipment — Cast components of double stud fitting assembly with a load capacity of
22 250 N (5 000 lbf), for aircraft cargo restraint
ISO 10254, Air cargo and ground equipment — Vocabulary
1) Endorsement of NAS 3610.
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ISO 16049-1:2013(E)
ISO 12118, Air cargo equipment — Identification of double-stud tie-down fittings having an omnidirectional
rated load capacity of 22 250 N (5 000 lbf) or above
ISO 16049-2, Air cargo equipment — Restraint straps — Part 2: Utilization guidelines and lashing conditions
ISO/PAS 21100, Air cargo unit load devices — Performance requirements and testing parameters
2)
European Aviation Safety Agency CS-25, Certification Specifications for Large Aeroplanes
3)
Japanese Airworthiness Standard Part 3 (Civil Aeronautics Law Article 10 § 4)
USA Code of Federal Regulations Title 14 CFR Part 25 — Airworthiness Standards: Transport Category
4)
Airplanes
European Technical Standard Order (ETSO) C-172, Cargo Restraint Strap Assemblies
3)
Federal Aviation Administration Technical Standard Order (TSO) C-172, Cargo Restraint Strap Assemblies
NOTE Also see informative references in Bibliography.
3 Terms and definitions
For the purpose of this document, the terms and definitions given in ISO 10254 and the following apply.
3.1
restraint strap assembly
elementary tie-down unit consisting of flat woven textile webbing (one fixed length end and one
adjustable end), one tensioning device and two end fittings, used for restraint of cargo on board civil
transport aircraft
3.2
tie-down
fact of restraining cargo movements in relation to an aircraft’s structure, throughout the range of
relative accelerations resulting from the allowable flight envelope, by means of an appropriate use of a
number of elementary tie-down devices against each direction of restraint
3.3
flat woven textile webbing
conventional or shuttleless woven narrow fabric made of continuous textile fibres, generally with
multiple plies, and the prime function of which is load bearing
Note 1 to entry: A characteristic of webbing is its tight woven fabric selvedge.
3.4
tensioning device
mechanical device inducing a tensile force in the load restraint assembly
EXAMPLE Ratchets, winches, over-centre buckles; see examples in Figure 1, C1 and C6.
2) EASA CS-25 constitutes the European governments transport aircraft airworthiness approval Regulations, and
it, as well as ETSO C-172, can be obtained from European Aviation Safety Agency (EASA), Otto Platz 1, Postfach
101253, D-50452 Cologne, Germany, or its web site at www.easa.europa.eu.
3) Japanese Airworthiness Standard Part 3 (ISBN 4-89279-661-1) can be obtained from the Civil Aviation Bureau
(CAB) of the Ministry of Land, Infrastructure and Transport, Tokyo, Japan, web site www.mlit.jp/en.
4) 14 CFR Part 25 constitutes the USA government transport aircraft airworthiness approval Regulations, and it,
as well as TSO C-172, can be obtained from US Government Printing Office, Mail Stop SSOP, Washington DC 20402-
9328, or its website at www.gpoaccess.gov/ecfr.
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ISO 16049-1:2013(E)
3.5
tension retaining device
metallic part connecting the webbing by clamping action and retaining the force induced in the tensioning
device by hand
EXAMPLE Cam buckles, sliding bar buckles; see example in Figure 1, F.
3.6
end fitting
metallic device connecting the webbing or the tensioning device to the attachment point on the aircraft
structure, the pallet edge rail or the load
Note 1 to entry: See examples in Figure 1, D1 to D6.
Note 2 to entry: The end fittings most commonly used on air cargo restraint straps include:
a) retainer equipped flat hook (see example in Figure 1, D1);
b) air cargo tie-down double stud (male) fitting conforming to ISO 9788 and ISO 12118, connected directly (sewn
to the webbing; see example in Figure 1, D3) or by an intermediate ring;
c) piece of aircraft restraint (female) rail conforming to ISO 7166.
3.7
tension force indicator
device that indicates the tensile force applied to the restraint strap assembly by means of the tensioning
device and movement of the load acting on the load restraint device
3.8
length of restraint strap assembly
3.8.1
fixed length
l
GF
length of a fixed end, measured from the force bearing point of the end fitting to the outer turning radius
of the connection of the webbing to the tensioning device
Note 1 to entry: See Figure 2.
Note 2 to entry: This length can be zero, i.e. the end fitting directly attached to the tensioning device.
3.8.2
adjustable length
l
GL
length of an adjustable end, measured from the free end of the webbing to the force bearing point of
the end fitting
Note 1 to entry: See Figure 2.
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ISO 16049-1:2013(E)
Key
A restraint strap assembly (complete) D end fittings
A1, A2 space for marking (label) D1 snap hook, flat, swivel or twisted, with retainer
B webbing D2 flat hook, with retainer
C tensioning devices D3 double stud tie-down fitting (directly sewn onto
webbing)
C1 ratchet tensioner D4 triangle, designed to engage with an anchorage
C2 ratchet tensioner with tension force indicator D5 connector to chain
(see also E)
C3 sliding bar buckle D6 wire claw hook (single or double)
C4, C5 over-centre buckles E tension force indicator (see also C2)
C6 lashing winch F tension retaining device (cam buckle, sliding bar
buckle)
Figure 1 — Examples of restraint strap equipment, including tensioning device C, end fitting D
and tension force indicator E
3.8.3
total length
l
(l ) + (l ) + length of the tensioning device
GF GL
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ISO 16049-1:2013(E)
Key
1 fixed end 3 end fitting
2 adjustable end 4 tensioning device or tension retaining device
Figure 2 — Two-piece restraint strap assembly
3.9
breaking force
BF
maximum force that the restraint strap assembly withstands when tested in a complete form, i.e. with
tensioning device and end fittings, according to 5.5
3.10
hand force
HF
force applied to the handle of the tensioning device, which creates the tensile force in the restraint
strap assembly
3.11
limit load
LL
maximum load to be expected in service
Note 1 to entry: See CS-25, JAS Part 3 or FAR Part 25, paragraph 25.301 (a).
Note 2 to entry: It is two thirds of the ultimate load (see hereafter), i.e. 14 827 N (3 333 lbf) for a typical rated
ultimate load of 22 250 N (5 000 lbf).
3.12
ultimate load
UL
limit load multiplied by a safety factor of 1,5
Note 1 to entry: see CS-25, JAS Part 3 or FAR Part 25, paragraph 25.303.
Note 2 to entry: It is used for computation of cargo tie-down arrangements, based on the ultimate load factors
defined in the Airworthiness Authorities approved Weight and Balance Manual, in each direction of restraint,
throughout the certified flight envelope of the aircraft type. The restraint strap assembly’s rated ultimate load is
guaranteed not to exceed the measured breaking force (BF).
3.13
residual tension
tension force which can be measured in the webbing of a strap assembly attached between two fixed
points, after its length was adjusted and its tension device was operated and latched with the reference
hand force (HF), prior to application of any external load
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ISO 16049-1:2013(E)
3.14
competent person
designated person, with suitable training, qualified by knowledge and practical experience and with the
necessary instructions to enable the required tests and examinations to be carried out
Note 1 to entry: A competent person can be suitably trained in accordance with ISO 9001:2008, 6.2.2.
3.15
traceability code
series of letters and/or numbers marked on a component or an assembly which enables its manufacturing
and in-service history to be retraced, including webbing production batch identification
Note 1 to entry: See 7.2.
4 Design criteria
4.1 General
4.1.1 This part of ISO 16049 specifies the design criteria for individual restraint strap assemblies, but
does not intend to specify, in any manner, the way they are to be used onboard aircraft to ensure proper
restraint throughout the certified flight envelope. Tie-down arrangements shall 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.
4.1.2 When restraint strap assemblies are attached to the edge rails of a certified air cargo pallet meeting
the requirements of ISO 8097 (NAS 3610) or ISO/PAS 21100, 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 (NAS 3610) or ISO/PAS 21100 configuration drawing(s).
4.1.3 The use of reliable and guaranteed restraint strap assemblies is necessary but not sufficient to
ensure flight safety; this part of ISO 16049 is based on the assumption that straps will be used and tie-down
will be performed in accordance with operating instructions established by the aircraft manufacturer, by
[4]
competent, suitably trained, personnel, for example as defined in ISO 9001:2008, 6.2.2 (see Reference
in the Bibliography).
4.1.4 Subject to proper operating instructions as per 4.1.1 and 4.1.2 being defined and complied with,
using restraint strap assemblies manufactured to an adequate design and a tested ultimate load capability
is nevertheless deemed necessary in order to ensure flight safety. General utilization guidelines and
calculation methods adequate to guarantee the effectiveness and ultimate load strength of the tie-down
arrangements performed to restrain cargo on board civil transport aircraft can be found in ISO 16049-2.
4.1.5 The restraint strap assembly shall be designed to be used on and compatible with:
a) the edge rails of air cargo pallets meeting the requirements of ISO 4117 or ISO 4171 [airworthiness
approved according to ISO 8097 (NAS 3610) or ISO/PAS 21100],
b) aircraft seat tracks or structural attachment points meeting the requirements of ISO 7166,
either directly, or using intermediate attachment hardware such as ISO 9788 double stud tie-down fittings.
4.2 Ultimate load
The breaking force (BF) of the restraint strap assembly, when tested in accordance with 5.5, shall
guarantee a rated minimum ultimate tensile load to be specified at purchasing as well as through
operating instructions.
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ISO 16049-1:2013(E)
The rated minimum ultimate load most commonly specified in the airline industry is 22 250 N (5 000 lbf).
This is compatible with the best omni-directional performance obtainable from structural attachment
points and intermediary hardware. In the interest of overall economy and world-wide standardization,
users are encouraged to use this value.
NOTE An example of justified deviation is where dedicated restraint straps are designed for use with ISO 7166
single stud tie-down fittings. Then, the rated ultimate load consistent with the fitting’s is 8 900 N (2 000 lbf).
4.3 Elongation
4.3.1 Care shall be taken in selecting the materials and design most appropriate for minimizing the
restraint strap assembly elongation under load, in order to improve its restraint capability.
4.3.2 The total elongation of the complete restraint strap assembly under load, as measured between
the force bearing point of the end fittings, i.e. the sum of webbing elongation and any longitudinal
deformation of the hardware (tensioning device or end fitting), shall not exceed 10 % when submitted to
the rated ultimate load (UL).
4.3.3 Webbing slippage through the tensioning device (see 4.7.5) is allowed only during pretension (i.e.
while the tensioning device is being actuated and latched), and if:
a) it does not exceed 0,5 % of the maximum total length of the complete restraint strap assembly, when
submitted to the residual tension force resulting from release of the tensioning device handle in the
closed position, and
b) it no longer occurs under any load between zero and the rated ultimate load (UL), after the tensioning
device handle has been latched.
4.3.4 The total elongation when submitted to intermediate loads shall not exceed the linear relationship
between the maximum values stated in 4.3.2 and 4.3.3 (see Figure 3).
Key
E Elongation
F Tensile force
R Residual load at tension
UL Ultimate load
A Allowable area
Figure 3 — Allowable elongation range
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ISO 16049-1:2013(E)
4.4 Flammability
The webbing, as used in the restraint strap assembly, i.e. including sewing and any treatment, shall meet
the flammability test criteria of CS-25, JAS Part 3 or FAR Part 25 Appendix F, Part I, paragraph (a)(1)(v);
it may not have a burn rate greater than 100 mm (4,0 in) per minute when tested horizontally with the
apparatus and test procedures required in Appendix F, Part I, paragraph (b)(5).
4.5 Environmental degradation
4.5.1 The available data concerning degradation of woven textile fibre performance when exposed to
environment factors, as provided in ISO/TR 8647, shall be taken into account for webbing and thread selection
and treatment, commensurate with the expected storage and service life of the restraint strap assembly.
4.5.2 An expiry date after which the rated performance may not be expected to be maintained shall
be provided to the purchaser at or before the time of delivery of each production batch, and shall be
marked on each strap as part of the required traceability code (see 7.2). The expiry date may take into
account the expected storage duration, providing the strap assemblies are delivered and stored in an
ultraviolet protective packaging, and any storage conditions requirements which might affect performance
degradation are specified.
4.5.3 For environmental degradation assessment, it should be assumed that the restraint strap
assemblies will be operated throughout temperature ranges of −40 °C (−40 °F) to 60 °C (140 °F) with
relative humidity between 20 % and 85 %, including ice, snow and occasional soaking in water.
4.5.4 In addition, the strap assembly components and materials should be selected in order to allow
separate recycling of the non-textile and webbing parts when the unit is out of use or after its expiry date.
Instructions for recycling should be provided by the manufacturer.
4.6 Dimensions
4.6.1 Length: the length of the fixed end (l ) and the adjustable end (l ) shall be specified by the purchaser.
GF GL
NOTE The length of the fixed end (l ) can be zero (end fitting attached directly to the tensioning device, or
GF
forming an integral part thereof). However, the use of such restraint strap assemblies is not recommended on air-
land pallets meeting the requirements of ISO 4117, when equipped with vertical mounted edge rail tie-down slots,
due to the risk of interference with aircraft restraint systems or an adjacent pallet during handling.
4.6.2 Width: the nominal width of the webbing, measured between the outer faces of selvedges, should
preferably be 51 ± 1 mm (2,00 ± 0,04 in) for a strap with a 22 250 N (5 000 Ibf) ultimate load rating. Width
between 38 mm (1,5 in) and 63 mm (2,5 in) is acceptable for the same load rat
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