ISO 20291-2:2021

Air cargo — Restraint slings — Part 2: Utilization requirements and recommendations and lashing calculations

1.1 This document provides general utilization requirements and recommendations and calculation methods adequate to guarantee the effectiveness and ultimate strength of tie-down/lashing arrangements performed to restrain cargo on board civil transport aircraft during flight, including the following: 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 ISO8097 (NAS 3610) 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 pallet (floating pallet) into either lower deck, main deck or upper deck containerized cargo compartments of an aircraft, when using for this purpose restraint slings (wire rope cables) specified in ISO 20291-1. 1.2 Restraint slings as specified in this document can also be used for permanent or semi-permanent attachment of a special purpose device, such as aircraft engine transport stand (see ISO 11241), horse stall (see ISO 9469), automobile transport device (see ISO 8268) or other, whether or not airworthiness approved, onto an aircraft pallet. 1.3 This document applies to cargo tie-down/lashing arrangements using exclusively air cargo restraint slings conforming to ISO 20291-1. NOTE Where tie-down is performed onto aircraft structure as per 1.1 b) or c), additional restrictions can be stated in the aircraft's authority approved Weight and Balance Manual. 1.4 This document specifies industry recognized means of complying with airworthiness authorities general regulations applicable to load securing on board civil transport aircraft (see 14 CFR Part 25 and EASA CS-25, CCAR-25 or Japanese Airworthiness Standard Part 3), and aircraft manufacturers authority approved Weight and Balance Manuals for each aircraft type as specified therein. 1.5 The wire rope slings in this document are intended exclusively for restraint purposes on board aircraft and are not intended to be used as lifting slings for handling or any other purpose.

Fret aérien — Élingues d'arrimage — Partie 2: Partie 2 : Exigences et recommandations d’utilisation et calculs d’arrimage

General Information

• Status: Published
• Publication Date: 21-Jun-2021
• ICS: 55.180.30 - Air mode containers, pallets and nets
• 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: 6060 - International Standard published
• Start Date: 22-Jun-2021
• Due Date: 16-May-2020
• Completion Date: 22-Jun-2021

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 20291-2
First edition
2021-06
Air cargo — Restraint slings —
Part 2:
Utilization requirements and
recommendations and lashing
calculations
Fret aérien — Élingues d'arrimage —
Partie 2: Partie 2 : Exigences et recommandations d’utilisation et
calculs d’arrimage
Reference number
ISO 20291-2:2021(E)
©
ISO 2021

---------------------- Page: 1 ----------------------
ISO 20291-2:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 20291-2:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 4
5 Specific requirements . 5
6 Rejection criteria. 7
7 Inspection . 7
8 Operator's responsibilities . 8
Bibliography . 9
© ISO 2021 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 20291-2:2021(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 (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.
A list of all parts in the ISO 20291 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 2021 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 20291-2:2021(E)

Introduction
This document specifies utilization requirements and recommendations and the principles to be used
in tie-down/lashing strength calculations when using air cargo restraint slings on board civil transport
aircraft.
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 of primary importance in providing safe air cargo restraint sling assemblies. Deviation
from the recommended criteria should only occur after careful consideration and thorough service
evaluation have shown that alternate methods can be used to provide an equivalent level of safety.
The requirements of this document are expressed in the applicable SI units, with approximate converted
values in inch-pound units between brackets for convenience in countries using that system.
Sling or cable assemblies made of steel wire rope are intended to be used in lieu of cargo restraint
straps meeting the requirements of ISO 16049-1, where straps inherent elongation under tension
appears unadvisable for a given tie-down arrangement. Typical examples of loads where substitution
of cables for straps throughout a given tie-down arrangement can be advisable are those for which
even limited movement during flight can be hazardous, such as heavy vehicles, aircraft engine stands,
helicopters, machinery.
On the date of publication of this document, no airworthiness approval procedure by Civil Aviation
Authorities is applicable to restraint slings. Their use for cargo restraint, however, remains subject to
the requirements of the approved aircraft type or sub-type Weight and Balance Manual.
The use of chains or other rigid devices for tie-down onto civil transport aircraft floor tracks is not
covered in this document; it is not recommended due to the possibility of generating excessive stresses
in the aircraft structure and is allowable only where explicitly approved in aircraft's authority approved
Weight and Balance Manual.
© ISO 2021 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 20291-2:2021(E)
Air cargo — Restraint slings —
Part 2:
Utilization requirements and recommendations and
lashing calculations
1 Scope
1.1 This document provides general utilization requirements and recommendations and calculation
methods adequate to guarantee the effectiveness and ultimate strength of tie-down/lashing arrangements
performed to restrain cargo on board civil transport aircraft during flight, including the following:
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 (NAS 3610) 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 pallet
(floating pallet) into either lower deck, main deck or upper deck containerized cargo compartments
of an aircraft,
when using for this purpose restraint slings (wire rope cables) specified in ISO 20291-1.
1.2 Restraint slings as specified in this document can also be used for permanent or semi-permanent
attachment of a special purpose device, such as aircraft engine transport stand (see ISO 11241), horse
stall (see ISO 9469), automobile transport device (see ISO 8268) or other, whether or not airworthiness
approved, onto an aircraft pallet.
1.3 This document applies to cargo tie-down/lashing arrangements using exclusively air cargo
restraint slings conforming to ISO 20291-1.
NOTE Where tie-down is performed onto aircraft structure as per 1.1 b) or c), additional restrictions can be
stated in the aircraft's authority approved Weight and Balance Manual.
1.4 This document specifies industry recognized means of complying with airworthiness authorities
general regulations applicable to load securing on board civil transport aircraft (see 14 CFR Part 25 and
EASA CS-25, CCAR-25 or Japanese Airworthiness Standard Part 3), and aircraft manufacturers authority
approved Weight and Balance Manuals for each aircraft type as specified therein.
1.5 The wire rope slings in this document are intended exclusively for restraint purposes on board
aircraft and are not intended to be used as lifting slings for handling or any other purpose.
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 2021 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO 20291-2:2021(E)

ISO 8097, Aircraft — Minimum airworthiness requirements and test conditions for certified air cargo unit
1)
load device
ISO 9788, Air cargo — Double stud tie-down fittings — Design and testing requirements
ISO 10254, Air cargo and ground equipment — Vocabulary
ISO 16049-2, Air cargo equipment — Restraint straps — Part 2: Utilization requirements and
recommendations and lashing calculations
ISO 20291-1:2021, Air cargo — Restraint slings — Part 1: Design and testing
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
[SOURCE: ISO 16049-2:2020, 3.1]
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
[SOURCE: ISO 16049-2:2020, 3.2]
3.3
flight envelope
set of allowable values for accelerations which can 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
[SOURCE: ISO 16049-2:2020, 3.3]
3.4
limit load
LL
maximum load to be expected in service as a result of the certified allowable flight envelope (3.3) of the
aircraft
Note 1 to entry: See 14 CFR Part 25 and CS-25, paragraph 25,301(a).
Note 2 to entry: It is two thirds of the ultimate load (3.5).
1) Endorsement of NAS 3610 revision 10, TSO/ETSO/CTSO/JTSO C-90c.
2 © ISO 2021 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 20291-2:2021(E)

[SOURCE: ISO 16049-2:2020, 3.4, modified — The abbreviated term "LL" has been removed; Note 1 to
entry has been added.]
3.5
ultimate load
UL
limit load (3.4) multiplied by a safety factor of 1,5
Note 1 to entry: See 14 CFR Part 25 and CS-25, paragraph 25, 303.
Note 2 to entry: It is used for the calculation of cargo tie-down arrangements (3.2), based on the ultimate load
factors defined in the airworthiness authority approved Weight and Balance Manual, in each direction of
restraint, throughout the certified flight envelope (3.3) of the aircraft type.
[SOURCE: ISO 16049-2:2020, 3.5, modified — The abbreviated term "UL" has been removed; in Note 1 to
entry, references to CCAR-25 and JAS Part 3 have been removed.]
3.6
fore
direction of restraint, relative to the aircraft structure, determined parallel to the aircraft centreline
towards the direction of flight
[SOURCE: ISO 16049-2:2020, 3.6]
3.7
aft
direction of restraint, relative to the aircraft structure, determined opposed to the aircraft centreline
towards the direction of flight
[SOURCE: ISO 16049-2:2020, 3.7]
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
[SOURCE: ISO 16049-2:2020, 3.8]
3.9
upward
upward direction relative to the aircraft structure
[SOURCE: ISO 16049-2:2020, 3.9]
3.10
load factor
-2
acceleration, expressed as multiples of the standard acceleration of gravity (“g” = 9,80665 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 the Airworthiness Authority approved Weight and Balance
Manual for an aircraft type or sub-type.
Note 2 to entry: The load factors may be limit or ultimate.
[SOURCE: ISO 16049-2:2020, 3.10]
© ISO 2021 – All rights reserved 3

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ISO 20291-2:2021(E)

3.11
strap
restraint strap assembly
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 (3.12), 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.
[SOURCE: ISO 16049-2:2020, 3.11, modified — "restraint strap assembly" has been changed to an
admitted term.]
3.12
fitting
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 straps (3.11) or other elementary tie-down (3.1) units 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 used in conjunction with restraint slings are double stud (ISO 9788) and
include an attachment ring.
[SOURCE: ISO 16049-2:2020, 3.12, modified — "fitting" has been added as a preferred term; a new Note
1 to entry has replaced the original one.]
3.13
floating pallet
air cargo pallet, or equivalent flat support device, 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
competent person
designated person, suitably trained, qualified by knowledge and practical experience and with the
necessary
...

INTERNATIONAL ISO
STANDARD 20291-2
First edition
Air cargo — Restraint slings —
Part 2:
Utilization requirements and
recommendations and lashing
calculations
PROOF/ÉPREUVE
Reference number
ISO 20291-2:2021(E)
©
ISO 2021

---------------------- Page: 1 ----------------------
ISO 20291-2:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 20291-2:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 4
5 Specific requirements . 5
6 Rejection criteria. 7
7 Inspection . 7
8 Operator's responsibilities . 8
Bibliography . 9
© ISO 2021 – All rights reserved PROOF/ÉPREUVE iii

---------------------- Page: 3 ----------------------
ISO 20291-2:2021(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 (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.
A list of all parts in the ISO 20291 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 PROOF/ÉPREUVE © ISO 2021 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 20291-2:2021(E)

Introduction
This document specifies utilization requirements and recommendations and the principles to be used
in tie-down/lashing strength calculations when using air cargo restraint slings on board civil transport
aircraft.
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 of primary importance in providing safe air cargo restraint sling assemblies. Deviation
from the recommended criteria should only occur after careful consideration and thorough service
evaluation have shown that alternate methods can be used to provide an equivalent level of safety.
The requirements of this document are expressed in the applicable SI units, with approximate converted
values in inch-pound units between brackets for convenience in countries using that system.
Sling or cable assemblies made of steel wire rope are intended to be used in lieu of cargo restraint
straps meeting the requirements of ISO 16049-1, where straps inherent elongation under tension
appears unadvisable for a given tie-down arrangement. Typical examples of loads where substitution
of cables for straps throughout a given tie-down arrangement can be advisable are those for which
even limited movement during flight can be hazardous, such as heavy vehicles, aircraft engine stands,
helicopters, machinery.
On the date of publication of this document, no airworthiness approval procedure by Civil Aviation
Authorities is applicable to restraint slings. Their use for cargo restraint, however, remains subject to
the requirements of the approved aircraft type or sub-type Weight and Balance Manual.
The use of chains or other rigid devices for tie-down onto civil transport aircraft floor tracks is not
covered in this document; it is not recommended due to the possibility of generating excessive stresses
in the aircraft structure and is allowable only where explicitly approved in aircraft's authority approved
Weight and Balance Manual.
© ISO 2021 – All rights reserved PROOF/ÉPREUVE v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 20291-2:2021(E)
Air cargo — Restraint slings —
Part 2:
Utilization requirements and recommendations and
lashing calculations
1 Scope
1.1 This document provides general utilization requirements and recommendations and calculation
methods adequate to guarantee the effectiveness and ultimate strength of tie-down/lashing arrangements
performed to restrain cargo on board civil transport aircraft during flight, including the following:
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 (NAS 3610) 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 pallet
(floating pallet) into either lower deck, main deck or upper deck containerized cargo compartments
of an aircraft,
when using for this purpose restraint slings (wire rope cables) specified in ISO 20291-1.
1.2 Restraint slings as specified in this document can also be used for permanent or semi-permanent
attachment of a special purpose device, such as aircraft engine transport stand (see ISO 11241), horse
stall (see ISO 9469), automobile transport device (see ISO 8268) or other, whether or not airworthiness
approved, onto an aircraft pallet.
1.3 This document applies to cargo tie-down/lashing arrangements using exclusively air cargo
restraint slings conforming to ISO 20291-1.
NOTE Where tie-down is performed onto aircraft structure as per 1.1 b) or c), additional restrictions can be
stated in the aircraft's authority approved Weight and Balance Manual.
1.4 This document specifies industry recognized means of complying with airworthiness authorities
general regulations applicable to load securing on board civil transport aircraft (see 14 CFR Part 25 and
EASA CS-25, CCAR-25 or Japanese Airworthiness Standard Part 3), and aircraft manufacturers authority
approved Weight and Balance Manuals for each aircraft type as specified therein.
1.5 The wire rope slings in this document are intended exclusively for restraint purposes on board
aircraft and are not intended to be used as lifting slings for handling or any other purpose.
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 2021 – All rights reserved PROOF/ÉPREUVE 1

---------------------- Page: 6 ----------------------
ISO 20291-2:2021(E)

ISO 8097, Aircraft — Minimum airworthiness requirements and test conditions for certified air cargo unit
1)
load devices
ISO 9788, Air cargo — Double stud tie-down fittings — Design and testing requirements
ISO 10254, Air cargo and ground equipment — Vocabulary
ISO 16049-2, Air cargo equipment — Restraint straps — Part 2: Utilization requirements and
recommendations and lashing calculations
ISO 20291-1:—, Air cargo — Restraint slings — Part 1: Design and testing
ISO 21100, Air cargo unit load devices — Performance requirements and test parameters
3 Terms and definitions
For the purpose of this document, the 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
[SOURCE: ISO 16049-2:2020, 3.1]
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
[SOURCE: ISO 16049-2:2020, 3.2]
3.3
flight envelope
set of allowable values for accelerations which can 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
[SOURCE: ISO 16049-2:2020, 3.3]
3.4
limit load
LL
maximum load to be expected in service as a result of the certified allowable flight envelope (3.3) of the
aircraft
Note 1 to entry: See 14 CFR Part 25 and CS-25, paragraph 25,301(a).
Note 2 to entry: It is two thirds of the ultimate load (3.5).
1) Endorsement of NAS 3610 revision 10, TSO/ETSO/CTSO/JTSO C-90c.
2 PROOF/ÉPREUVE © ISO 2021 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 20291-2:2021(E)

[SOURCE: ISO 16049-2:2020, 3.4, modified — The abbreviated term "LL" has been removed; Note 1 to
entry has been added.]
3.5
ultimate load
UL
limit load (3.4) multiplied by a safety factor of 1,5
Note 1 to entry: See 14 CFR Part 25 and CS-25, paragraph 25,303.
Note 2 to entry: It is used for the calculation of cargo tie-down arrangements (3.2), based on the ultimate load
factors defined in the airworthiness authority approved Weight and Balance Manual, in each direction of
restraint, throughout the certified flight envelope (3.3) of the aircraft type.
[SOURCE: ISO 16049-2:2020, 3.5, modified — The abbreviated term "UL" has been removed; in Note 1 to
entry, references to CCAR-25 and JAS Part 3 have been removed.]
3.6
fore
direction of restraint, relative to the aircraft structure, determined parallel to the aircraft centreline
towards the direction of flight
[SOURCE: ISO 16049-2:2020, 3.6]
3.7
aft
direction of restraint, relative to the aircraft structure, determined opposed to the aircraft centreline
towards the direction of flight
[SOURCE: ISO 16049-2:2020, 3.7]
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
[SOURCE: ISO 16049-2:2020, 3.8]
3.9
upward
upward direction relative to the aircraft structure
[SOURCE: ISO 16049-2:2020, 3.9]
3.10
load factor
-2
acceleration, expressed as multiples of the standard acceleration of gravity (“g” = 9,80665 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 the Airworthiness Authority approved Weight and Balance
Manual for an aircraft type or sub-type.
Note 2 to entry: The load factors may be limit or ultimate.
[SOURCE: ISO 16049-2:2020, 3.10]
© ISO 2021 – All rights reserved PROOF/ÉPREUVE 3

---------------------- Page: 8 ----------------------
ISO 20291-2:2021(E)

3.11
strap
restraint strap assembly
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 (3.12), 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.
[SOURCE: ISO 16049-2:2020, 3.11, modified — "restraint strap assembly" has been changed to an
admitted term.]
3.12
fitting
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 straps (3.11) or other elementary tie-down (3.1) units 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 used in conjunction with restraint slings are double stud (ISO 9788) and
include an attachment ring.
[SOURCE: ISO 16049-2:2020, 3.12, modified — "fitting" has been added as a preferred term; a new Note
1 to entry has replaced the original one.]
3.13
floating pallet
air cargo pallet, or equivalent flat support device, 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
competent person
designated person, suitably trained, qualified by knowledge and practical experience and with the
necessary instructions to enable the required tests and examinations to be ca
...