ISO 8267-2:2023

Aircraft - Tow bar attachment fittings interface requirements - Part 2: Regional aircraft

This document specifies the interface requirements for tow bar attachment fittings on the nose gear (when towing operations are performed from the nose gear) of conventional tricycle type landing gears of commercial civil transport aircraft. This document is applicable to all new models of regional aircraft within the specified maximum ramp mass range which enter service or are designed after its date of publication. It does not apply to previously in-service regional aircraft models, which present a considerable variety of tow bar attachment fittings. However, a simple retrofit modification is described that can make certain in-service fittings compatible with a tow bar head in conformity with this document, where deemed appropriate in order to facilitate operation of such aircraft types at airports. This document is applicable to regional commercial transport aircraft airworthiness certified with a maximum ramp mass of ≤ 50 000 kg (110 000 lb). It does not apply to: - aircraft airworthiness certified as commuter category aeroplanes; - aircraft airworthiness certified as main line aircraft with a maximum ramp mass of > 50 000 kg (110 000 lb), which are covered by ISO 8267-1.

Aéronefs — Exigences d'interface des ferrures d'attache de barre de tractage — Partie 2: Aéronefs régionaux

General Information

• Status: Published
• Publication Date: 05-Dec-2023
• ICS: 49.100 - Ground service and maintenance 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: 6060 - International Standard published
• Start Date: 06-Dec-2023
• Due Date: 14-Oct-2023
• Completion Date: 06-Dec-2023

Relations

• Revises: ISO 8267-2:2019 - Aircraft - Tow bar attachment fittings interface requirements - Part 2: Regional aircraft
• Effective Date: 06-Jun-2022

Overview

ISO 8267-2:2023 specifies interface requirements for tow bar attachment fittings on the nose landing gear of regional commercial transport aircraft (designs entering service after publication). The standard applies to regional aircraft with a maximum ramp mass up to 50 000 kg (110 000 lb) and aims to standardize tow bar interfaces so a single tow bar type can serve multiple aircraft models.

Key benefits: reduced towing equipment variety, improved ground handling efficiency, consistent safety margins, and defined retrofit paths for some in-service aircraft.

Key Topics

• Scope and applicability: Applies to new regional aircraft models within the specified maximum ramp mass range. It excludes commuter-category aeroplanes and main line aircraft covered by ISO 8267-1.

• Fitting location: Requires a forward, easily accessible attachment on the nose gear for push/pull towing. Rear fittings are not required; an axle fitting may be used for two-wheel nose gears if towing loads are within limits.

• Towing loads and compliance: Towing load capability must meet applicable airworthiness regulations (e.g., 14 CFR Part 25, EASA-CS 25, paragraph 25.509). The standard provides the towing-load basis and ensures fittings are designed to withstand specified limit loads.

• Fitting configuration and dimensions: The standard specifies a horizontal cylindrical pin as the nominal fitting configuration. Nominal pin dimensions by category (from the standard) include:

  • Category I: diameter 19.05 mm (0.75 in), length 38.10 mm (1.50 in)
  • Category II: diameter 25.40 mm (1.00 in), length 63.50 mm (2.50 in) The tow bar device must grip the pin uniformly over approximately 93–95% of the pin length and be adjustable to provide positive engagement when locked.

• Mass categories and design guidance: Aircraft families that bridge mass categories are advised to adopt a single fitting interface, typically the higher-category dimensions, to avoid changes during development and to accommodate potential mass growth.

Applications

• Aircraft OEMs: design nose-gear fittings to conform to the standardized interface and towing-load requirements.
• Airport ground handlers and operators: use standardized tow bars across regional fleets to reduce inventory and complexity.
• Maintenance and retrofit teams: apply the document’s described retrofit option where appropriate to render certain in-service fittings compatible with standardized tow bar heads. The standard includes an example retrofit using a machined spacer (approx. 0.23 kg) for converting existing fittings.

Related Standards

• ISO 8267-1 - Tow bar attachment fittings interface requirements - Part 1: Main line aircraft
• Regulatory references: 14 CFR Part 25 and EASA-CS Part 25 (paragraph 25.509 on towing loads)

ISO 8267-2:2023 is focused on practical, safety-driven standardization of tow bar interfaces for regional aircraft to streamline ground operations while ensuring compliance with airworthiness towing-load requirements.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8267-2
Fourth edition
2023-12
Aircraft — Tow bar attachment fittings
interface requirements —
Part 2:
Regional aircraft
Aéronefs — Exigences d'interface des ferrures d'attache de barre de
tractage —
Partie 2: Aéronefs régionaux
Reference number
© ISO 2023
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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Published in Switzerland
ii
Contents  Page
Foreword .iv
Introduction .v
1 Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Requirements . 2
4.1 Fitting location . 2
4.2 Towing loads . 2
4.3 Aircraft mass categories . 2
4.4 Fitting configuration, dimensions and clearances . 2
4.5 Tow bar fit . 3
5  Retrofit option . 3
Bibliography . 5
iii
Foreword
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electrotechnical standardization.
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www.iso.org/iso/foreword.html.
This document was prepared by ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 9, Air cargo
and ground equipment.
This fourth edition cancels and replaces the third edition (ISO 8267-2:2019), which has been technically
revised.
The main changes are as follows:
— the normative and aircraft airworthiness references have been updated.
A list of all parts in the ISO 8267 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
Introduction
The purpose of this document is to achieve tow bar attachment fittings interface standardization by
aircraft mass category (which determines tow bar forces) in order to ensure that a single type of tow
bar with a standard connection can be used for all aircraft types within or near that mass category,
so as to assist operators and airport handling companies in reducing the number of different tow bar
types used.
In this document, the following verbal forms are used:
— “shall” indicates a requirement;
— “should” indicates a recommendation;
— “may” indicates a permission;
— “can” indicates a possibility or a capability.
Recommended criteria are, while not mandatory, considered to be of primary importance in providing
safe aircraft towing arrangements. Deviation from recommended criteria should only occur after
careful consideration, extensive testing, and tho
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