ISO 16049-2:2020

Air cargo equipment - Restraint straps - Part 2: Utilization requirements and recommendations and lashing calculations

This document aims at providing general utilization requirements and recommendations and calculation methods adequate to guarantee the effectiveness and ultimate load strength of tie-down/lashing arrangements performed to restrain cargo 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 or main deck or upper deck cargo systems meeting the restraint requirements of air cargo pallets approved in accordance with ISO 8097 (NAS3610) or ISO 21100, or b) additional tie-down on aircraft structure when necessitated by pallet maximum gross mass or centre of gravity limits, or c) 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, or d) individual pieces of load loaded in non-containerized (bulk loaded) baggage or cargo compartments. This document applies to cargo tie-down/lashing arrangements using exclusively air cargo restraint straps conforming to ISO 16049-1. Its general recommendations may also be used for tie-down arrangements using other means (e.g. steel cables, rope, other types of straps), but under the user's responsibility as to their adequacy and the strength calculations required. NOTE 1 Where tie-down is performed onto aircraft structure as per b) or c) above, additional restrictions can be stated in the aircraft's Authority approved Weight and Balance Manual. NOTE 2 The use of chains, rods, or other rigid devices for tie-down onto civil transport aircraft floor tracks, which can generate excessive stress in the aircraft structure, is not part of the scope of this document. . This document aims at providing industry recognized means of complying with Airworthiness Authorities general requirements applicable to load securing on board civil transport aircraft (see CCAR-25, JAS Part 3, 14 CFR Part 25 and EASA CS-25), and aircraft manufacturers Authority approved Weight and Balance Manuals for each aircraft type as specified therein. It is not the intent of this document to specify when restraint straps should be used, but how they should be used. Meeting the methods requirements of this document is not alone sufficient to ensure flight safety: this document is based on the assumption that cargo tie-down will be designed, performed, and checked prior to aircraft departure in accordance with appropriate operating instructions conforming to the Weight and Balance Manual of the aircraft concerned, by competent, suitably trained, personnel as defined for example in ISO 9001:2015, 6.2.2 (see Clause 8).

Équipement pour le fret aérien — Sangles d'arrimage — Partie 2: Titre manque

General Information

• Status: Published
• Publication Date: 09-Jan-2020
• ICS: 49.120 - Cargo equipment
• Technical Committee: ISO/TC 20/SC 9 - Air cargo and ground equipment
• Drafting Committee: ISO/TC 20/SC 9 - Air cargo and ground equipment
• Current Stage: 9060 - Close of review
• Completion Date: 02-Sep-2030

Relations

• Revises: ISO 16049-2:2013 - Air cargo equipment - Restraint straps - Part 2: Utilization guidelines and lashing calculations
• Effective Date: 30-Jan-2016

Overview

ISO 16049-2:2020 - "Air cargo equipment - Restraint straps - Part 2" provides utilization requirements, recommendations and lashing calculation methods to ensure effective and reliable tie-down/lashing arrangements for cargo carried on civil transport aircraft. It covers cargo secured on certified air cargo pallets, additional tie-downs to aircraft structure, non‑unitized items (including floating pallets) and bulk-loaded pieces. The standard specifies how to use air cargo restraint straps (used in accordance with ISO 16049-1) and provides industry-recognized methods to help meet airworthiness authority load-securing requirements (e.g., 14 CFR Part 25, EASA CS‑25).

Key Topics and Requirements

• Scope of application: Tie-down arrangements for pallets, floating pallets, non-unitized cargo and bulk-loaded compartments; excludes rigid devices (chains/rods) that can overstress aircraft structure.
• Restraint strap use: Applies to straps conforming to ISO 16049-1; offers recommendations that may be adapted for other lashing means at the user's responsibility.
• Tie-down methods: Geometric layouts, directions of restraint (fore, aft, side, upward) and basic tie-down practices.
• Lashing calculations: Load factors from the aircraft Weight and Balance Manual, calculation principles, practical calculation procedures and a provided calculation sheet (Clause 6.4) to document design/verification.
• Load definitions: Clarifies limit load and ultimate load (ultimate = limit × 1.5) and use of ultimate load factors for strength verification.
• Specific considerations: Risk of slippage, tilting, long/narrow items, maximum number of tie-down locations and pallet edge-rail constraints.
• Operator responsibilities: Requirement for documented operating instructions, compliance with the applicable Weight and Balance Manual, and use of competent, trained personnel (see ISO 9001 example).

Practical Applications

• Designing and validating cargo tie-down/lashing arrangements for commercial and freighter aircraft.
• Preparing load‑securing procedures, checklists and operating instructions for airline operations and ground handling.
• Performing lashing strength calculations for unusual loads, floating pallets or additional structure tie-downs.
• Training loadmasters, cargo handlers, safety engineers and auditors in compliant strap use and calculation methods.

Who Should Use This Standard

• Airline operations and cargo divisions
• Freight forwarders and ground-handling companies
• Aircraft loadmasters and cargo planners
• Aircraft manufacturers and structural engineers (for tie-down interface)
• Aviation safety regulators and auditors
• Training providers for cargo handling and load securing

Related Standards

• ISO 16049-1 (restraint strap design & testing)
• ISO 8097, ISO 21100 (air cargo pallet/unit load devices)
• ISO 7166, ISO 9788, ISO 10254
• Airworthiness regulations: 14 CFR Part 25, EASA CS‑25, CCAR‑25, JAS Part 3

Keywords: ISO 16049-2:2020, air cargo restraint straps, lashing calculations, tie-down, air cargo pallets, Weight and Balance Manual, aircraft load securing.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 16049-2
Third edition
2020-01
Air cargo equipment — Restraint
straps —
Part 2:
Utilization requirements and
recommendations and lashing
calculations
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 4
5 Tie-down method . 8
5.1 Basic method . 8
5.2 Directions of restraint . 8
6 Calculation methods . 9
6.1 Load factors . 9
6.2 Calculation principles .10
6.3 Practical calculation.11
6.4 Calculation sheet .11
7 Specific requirements .12
7.1 General .12
7.2 Risk of cargo slippage .13
7.3 Risk of cargo tilting .13
7.4 Long and narrow items .13
8 Operator's responsibilities .14
Bibliography .16
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
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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 (see 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 (see 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.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles,
Subcommittee SC 9, Air cargo and ground equipment.
This third edition cancels and replaces the second edition (ISO 16049-2:2013), which has been
technically revised. The main changes compared to the previous edition are as follows::
— new 4.14, Figure 3 and Table 1 regarding maximum number of tie-down locations on a pallet;
— deletion in 5.1, Basic methods, of Figure 4 former first drawing without lateral restraint
dedicated straps;
— specification in 6.2, Calculation principles, of centreline angle and floor angle;
— deletion in 6.3, Practical calculation, and Bibliography of references to IATA AHM 311 and AHM 450;
— new 6.4, Calculation sheet.
A list of all parts in the ISO 16049 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

Introduction
This document specifies utilization guidelines and the principles to be used in tie-down/lashing
strength calculations for the use of air cargo restraint straps on board civil transport aircraft.
The civil aviation requirements referred to in the present document are those relating to operation
of transport aircraft. They constitute the set of operation requirements internationally agreed in
application of International Civil Aviation Organization (ICAO) Annex 6, Operation of aircraft, to the
Convention on International Civil Aviation.
Throughout this document, 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 lashing arrangements. Deviation from
recommended criteria should only occur after careful consideration and thorough service evaluation
have shown the alternate methods ensure the same level of safety.
The requirements of this document are expressed in the applicable SI units, with approximate inch-
pound units conversion between brackets for convenience in those countries using that system.
INTERNATIONAL STANDARD ISO 16049-2:2020(E)
Air cargo equipment — Restraint straps —
Part 2:
Utilization requirements and recommendations and
lashing calculations
1 Scope
This document aims at providing general utilization requirements and recommendations and
calculation methods adequate to guarantee the effectiveness and ultimate load strength of tie-down/
lashing arrangements performed to restrain cargo 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 or main deck or upper deck cargo systems meeting the restraint
requirements of air cargo pallets approved in accordance with ISO 8097 (NAS3610) or ISO 21100, or
b) additional tie-down on aircraft structure when necessitated by pallet maximum gross mass or
centre of gravity limits, or
c) 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, or
d) individual pieces of load loaded in non-containerized (bulk loaded) baggage or cargo compartments.
This document applies to cargo tie-down/lashing arrangements using exclusively air cargo restraint
straps conforming to ISO 16049-1. Its general recommendations may also be used for tie-down
arrangements using other means (e.g. steel cables, rope, other types of straps), but under the user’s
responsibility as to their adequacy and the strength calculations required.
NOTE 1 Where tie-down is performed onto aircraft structure as per b) or c) above, additional restrictions can
be stated in the aircraft's Authority approved Weight and Balance Manual.
NOTE 2 The use of chains, rods, or other rigid devices for tie-down onto civil transport aircraft floor tracks,
which can generate excessive stress in the aircraft structure, is not part of the scope of this document. .
This document aims at providing industry recognized means of complying with Airworthiness
Authorities general requirements applicable to load securing on board civil transport aircraft (see
CCAR-25, JAS Part 3, 14 CFR Part 25 and EASA CS-25), and aircraft manufacturers Authority approved
Weight and Balance Manuals for each aircraft type as specified therein. It is not the intent of this
document to specify when restraint straps should be used, but how they should be used.
Meeting the methods requirements of this document is not alone sufficient to ensure flight safety: this
document is based on the assumption that cargo tie-down will be designed, performed, and checked
prior to aircraft departure in accordance with appropriate operating instructions conforming to the
Weight and Balance Manual of the aircraft concerned, by competent, suitably trained, personnel as
defined for example in ISO 9001:2015, 6.2.2 (see Clause 8).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 7166, Aircraft — Rail and stud configuration for passenger equipment and cargo restraint
1)
ISO 8097:2001 , Aircraft — Minimum airworthiness requirements and test conditions for certified air
cargo unit load devices
ISO 9788, Air cargo — Double stud tie-down fittings — Design and testing requirements
ISO 10254, Air cargo and ground equipment — Vocabulary
ISO 16049-1, Air cargo equipment — Restraint straps — Part 1: Design criteria and testing methods
ISO 21100, Air cargo unit load devices — Performance requirements and test parameters
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10254 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
tie-down
lashing
fact of restraining cargo movements in relation to an aircraft’s structure, throughout the range of
relative accelerations resulting from the allowable flight envelope (3.3), by means of an appropriate use
of a number of elementary tie-down devices against each direction of restraint
3.2
tie-down arrangement
geometric layout of an assembly of elementary tie-down (3.1) devices affixed and tensioned around a
piece of cargo in order to ensure its tie-down against each direction of restraint
3.3
flight envelope
set of allowable values for accelerations which may be
encountered during flight in the various directions relative to the aircraft’s structure, as determined
during the aircraft certification flight testing and certified by the Airworthiness Authority within the
aircraft’s type certificate
3.4
limit load
LL
maximum load to be expected in service as a result of the certified flight envelope (3.3) of the aircraft
Note 1 to entry: It is two thirds of the ultimate load (3.5).
3.5
ultimate load
UL
limit load (3.4) multiplied by a safety factor of 1,5
Note 1 to entry: See CCAR-25, JAS Part 3, 14 CFR Part 25 and CS-25, paragraph 25.303.
Note 2 to entry: It is used for calculation of cargo tie-down arrangements (3.2), based on the ultimate load factors
(3.10) defined in the Airworthiness Authority approved Weight and Balance Manual (3.14), in each direction of
restraint, throughout the certified flight envelope (3.3) of the aircraft type.
1) Endorsement of NAS 3610 revision 10, TSO/ETSO/CTSO/JTSO C-90c.
2 © ISO 2020 – All rights reserved

3.6
fore
direction of restraint, relative to the aircraft structure, determined parallel to the aircraft centreline
towards the direction of flight
3.7
aft
directions of restraint, relative to the aircraft structure, determined parallel to the aircraft centreline
opposite to the direction of flight
3.8
side
direction of restraint, relative to the aircraft structure, determined perpendicular to the aircraft
centreline and parallel to its floor, left-hand or right-hand
3.9
upward
upward direction relative to the aircraft structure
3.10
load factor
−2
acceleration, expressed as a multiple of the standard acceleration of gravity (“g” = 9,806 65 m.s ), in
each direction of restraint ( fore (3.6), aft (3.7), sides (3.8), upward (3.9)), that will result in limit or
ultimate, as is the case, forces on the tie-down arrangement (3.2) proportional to the mass of the piece
of cargo being restrained
Note 1 to entry: The load factors are provided by Airworthiness Authority approved Weight and Balance Manual
(3.14) for aircraft type or sub-type.
Note 2 to entry: The load factors may be limit or ultimate.
3.11
restraint strap assembly
strap
basic tie-down (3.1) unit consisting of flat woven textile webbing (one fixed end and one adjustable end),
one tensioning device and two end fittings, used for restraint of cargo on board civil transport aircraft
Note 1 to entry: See ISO 16049-1 for description, design criteria and testing requirements.
3.12
tie-down fitting
basic piece of hardware, either single stud (see ISO 7166) or double stud (see ISO 9788), with an omni-
directional capability, allowing to attach (a) strap(s) (3.11) or other elementary tie-down (3.1) unit(s) to
the floor tracks or tie-down receptacles of an aircraft’s structure or the edge tracks of an air cargo pallet
Note 1 to entry: Tie-down fittings most commonly include an attachment ring, but may also be directly sewn
onto a strap as a permanent end fitting thereof (see ISO 16049-1).
3.13
floating
located onto an aircraft’s cargo compartment
rollerized conveyor but not restrained by the cargo system, the pallet and its load constituting “non-
unitized” cargo and being restrained by a set of straps (3.11) attached to aircraft structural points
3.14
Weight and Balance Manual
WBM
manual, or sub-part of the Airplane Flight Manual, approved by the appropriate airworthiness
Authorities as part of aircraft type certification
Note 1 to entry: It may be part of the Type Certificate (TC) of the aircraft type or sub-type concerned, or of
a Supplemental Type Certificate (STC) for an aircraft type's conversion or its cargo loading system. A WBM
Supplement, where provided, forms part of the approved WBM.
3.15
competent person
designated person, with suitable training, qualified by knowledge and practical experience and with
the necessary operating instructions established
Note 1 to entry: A competent person can be suitably trained in accordance with, for example ISO 9001:2015, 6.2.2
or another equivalent quality management standard.
Note 2 to entry: See 4.1 for the operating instructions.
4 General requirements
4.1 Operating instructions shall be established by the aircraft operator, under control of his reporting
Civil Aviation Authority. The operating instructions shall identify the general airworthiness requirements
and the applicable aircraft Weight and Balance Manual, and should incorporate the requirements of this
document, or an equivalent industry standard (see Bibliography).
4.2 In addition, when restraint straps are attached to the edge rails of a certified air cargo pallet
meeting the requirements of ISO 8097 (NAS 3610) or ISO 21100, operating instructions shall take into
account the general requirements of the appropriate ISO 8097 (NAS 3610) or ISO 21100 configuration
drawing(s) as to tie-down points locations and spacings.
4.3 Actual tie-down/lashing on pallets or aircraft in accordance with these instructions shall be
performed and checked exclusively by competent, suitably trained, personnel. For example, the
personnel trained in accordance with ISO 9001:2015, 6.2.2 or equivalent pertinent industry training and
proficiency standards (see Clause 8) is advised.
4.4 Regardless of the tie-down method used (see Clause 5), all the following general rules shall be
complied with.
4.5 Tie-down shall be performed using straps designed and tested in accordance with ISO 16049-1,
onto tracks or receptacles meeting the requirements of ISO 7166, and using fittings meeting the
requirements of either ISO 7166 (single stud) or ISO 9788 (double stud). It is presupposed that the tie-
down is approved under TSO/ETSO/CTSO/JTSO C172a.
It is presupposed that the rated ultimate strength resulting from testing of the strap model used is
used for calculation of the tie-down arrangement’s strength (see Clause 6), using the safety factor
of 1,5 prescribed by applicable regulations, e.g. CCAR-25, JAS Part 3, 14 CFR Part 25 and CS-25,
paragraph 25.303. In the event of other straps or alternate tie-down equipment (e.g. ropes, cables)
being used under the operator’s responsibility, the following general rules shall nevertheless apply, and
the minimum guaranteed ultimate strength of the specific equipment used shall be used for strength
calculation.
4.6 If several elements (e.g. straps, fittings, structural attachment points) of different ultimate strengths
are used together, the strength of the resulting total tie-down element shall be limited to the strength of
the weakest item.
4 © ISO 2020 – All rights reserved

4.7 A total tie-down arrangement should be performed using exclusively straps of the same model, in
order to ensure differences in elasticity will not result in unequal tension of the straps and premature
failure of certain ones in the event of a major acceleration being encountered during flight. If different
models must be used, at least the straps material (e.g. polyamide, polyester, etc.) and rated ultimate
strength shall be identical for any single direction of restraint.
4.8 Tie-down arrangements shall be symmetrical, i.e. performed using an equal number of tie-down
attachment points (fittings or equivalent) on any two opposite sides of the piece of cargo, and the same
number of straps, acting in the same direction(s) of restraint, onto any two symmetrically located
attachment points. See Figure 1.
4.9 A single tie-down fitting may, subject to ring geometrical compatibility and any Weight and Balance
Manual restrictions or limits as to load factors simultaneity, be attached to up to three straps acting in
as many different directions onto a pallet, but shall be attached to no more than one acting in any single
direction of restraint (fore, aft, side or upward). When attaching more than one strap to a ring with hooks,
the hooks shall fit in the ring and line up in the applicable directions of restraint.
NOTE Attaching more than one strap to a given structural attachment point is not allowed at certain aircraft
locations: see the applicable Weight and Balance Manual.
4.10 A strap attached to fittings on opposite sides of the piece of cargo and passing over or around it
is to be accounted for twice the rated ultimate load capacity of its weakest attachment point, under the
requirement that the strap remains free to slide along the piece of cargo and not attached to it, so that the
load is equally distributed between both ends of the strap. A strap attached to the piece of cargo may be
accounted for only once.
4.11 The tie-down arrangement shall prevent cargo from overturning. For upward restraint, a minimum
of two straps, regardless of the mass to be restrained, shall be used over the top of the piece of cargo, one
on each side of its centre of gravity. When a higher number of upward straps is used, they should be
evenly distributed around the centre of gravity, and the straps should be distributed as far forward and
aft as possible from the centre of gravity in order to withstand the overturning moment. At least half the
straps for horizontal (forward, aft and side) restraint should contact or be attached to the cargo higher
than its centre of gravity.
4.12 Each strap should make a minimum possible angle, not to exceed 30 °C with the direction of
restraint for which it is accounted for (see Figure 1). In practical terms, to ensure angles a , a , a in
1 2 3
Figure 1 be no more than 30 °C in relation with, respectively, directions A, B and C, it should be checked
that distances d , d and d , respectively, are less than half of distances D , D and D .
1 2 3 1 2 3
The angles a , a , a shall not be confused with a strap’s floor angle and centreline angle. The floor angle
1 2 3
and centreline angle of a strap are to be used to calculate a strap’s restraint capability in each direction:
see 6.2.2.
Figure 1 — Angles
4.13 A minimum distance of 0,5 m (20 in) shall be maintained on a pallet between any two tie-down
attachment points (fittings) bearing straps ensuring restraint in the same direction (see examples in
Figure 2).
FORBIDDEN ALLOWABLE ALLOWABLE
(spacing < 50 cm) (different directions) (50 cm spacing minimum)
Figure 2 — Minimum distances
For this purpose, a strap shall be considered as acting in one direction if it makes a minimum possible
angle, not to exceed 30 °C, with this direction. The load vector components in the other directions,
resulting from this angle, may be neglected if the loads in these other directions are taken up by other
dedicated straps, themselves forming a minimum angle with the direction concerned.
4.14 A minimum distance of 0,4 m (16 inch) shall be maintained between any tie-down attachment
point (fitting) and an adjacent pallet c
...